LOEWE CALIDA 72 Super Flatline Art. Nr. 52460 L17 YEAR 1993.

THE LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17 A top television set from LOEWE a no more officially alive GERMAN manufacturer.

The LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17 First LOEWE introducing the Super Flatline CRT (PHILIPS ESF CRT TUBE)  type and big screen format in that kind of model.

It's 29 inches (72Cm) with superb crisp cracking picture without rivals, plus stereo sound and teletext, and advanced OSD menu type.
The LOEWE C9003 chassis, here featured was also used in:

LOEWE 51415, 51423, 51424, 51470, 53441, 53442, 53443, 53446, 53447, 53448, 60407, ARTV2/32, CALIDA-70, 72 CONCEPT-PLUS-1700, CONCEPT-PLUS763, CONCEPT-PLUS770, CONTUR-630, CONTUR-700, CONTUR-PLUS630, CONTUR-PLUS700, PROFI-763, PROFI-770, PROFI-863, PROFI-870, PROFI-963, PROFI-970

The   LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17   is a DIGITAL Colour television receiver or set , are known in which the majority of signal processing that takes place therein is carried out digitally. That is, a video or television signal is received in a conventional fashion using a known analog tuning circuit and then, following the tuning operation, the received analog television signal is converted into a digital signal and digitally processed before subsequently being converted back to an analog signal for display on a colour cathode ray tube.

In a conventional television receiver, all signals are analog-processed. Analog signal processing, however, has the problems at the video stage and thereafter. These problems stem from the general drawbacks of analog signal processing with regard to time-base operation, specifically, incomplete Y/C separation (which causes cross color and dot interference), various types of problems resulting in low picture quality, and low precision of synchronization. Furthermore, from the viewpoints of cost and ease of manufacturing the analog circuit, a hybrid configuration must be employed even if the main circuit comprises an IC. In addition to these disadvantages, many adjustments must be performed.

In order to solve the above problems, it is proposed to process all signals in a digital form from the video stage to the chrominance signal demodulation stage. In such a digital television receiver, various improvements in picture quality should result due to the advantages of digital signal processing.

Therefore digital television signal processing system introduced in 1984 by the Worldwide Semiconductor Group (Freiburg, West Germany) of International Telephone and Telegraph Corporation is described in an ITT Corporation publication titled "VLSI Digital TV System--DIGIT 2000." In that system color video signals, after being processed in digital (binary) form, are converted to analog form by means of digital-to-analog converters before being coupled to an image displaying kinescope. The analog color video signals are coupled to the kinescope via analog buffer amplifiers and video output kinescope driver amplifiers which provide video output signals at a high level suitable for driving intensity control electrodes of the kinescope.


The LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17  Is a multistandard set and relates to a digital multistandard decoder for video signals and to a method for decoding video signals.
Colour video signals, so-called composite video, blanking and sync signals (CVBS) are essentially composed of a brightness signal or luminance component (Y), two colour difference signals or chrominance components (U, V or I, Q), vertical and horizontal sync signals (VS, HS) and a blanking signal (BL).

The different coding processes, e.g. NTSC, PAL and SECAM, introduced into the known colour television standards, differ in the nature of the chrominance transmission and in particular the different systems make use of different colour subcarrier frequencies and different line frequencies.
The following explanations relate to the PAL and NTSC systems, but correspondingly apply to video signals of other standards and non-standardized signals.
The colour subcarrier frequency (fsc) of a PAL system and a NTSC system is fsc(NTSC) = 3.58 MHz or fsc(PAL) = 4.43 MHz.
In addition, in PAL and NTSC systems the relationships of the colour subcarrier frequency (fsc) to the line frequency (fh) are given by fsc(NTSC) = 227.50 * fh or 4•fsc(NTSC) = 910 • fh fsc(PAL) = 283.75 * fh or 4•fsc(PAL) = 1135 • fh so that the phase of the colour subcarrier in the case of NTSC is changed by 180°/line and in PAL by 270°/line.

In the case of digital video signal processing and decoding the prior art fundamentally distinguishes between two system architectures. These are the burst-locked architecture and the line-locked architecture, i.e. systems which operate with sampling frequencies for the video signal, which are produced in phase-locked manner to the colour subcarrier frequency transmitted with the burst pulse or in phase-locked manner with the line frequency, respectively.

The principal advantage of the present invention is a color television receiver is provided having a fully digital color demodulator wherein the luminance signal and the chrominance signals are separated and digitally processed prior to being converted to analog signals in that the all-digital signal processing largely eliminates the need for nonintegratable circuit elements, i.e., particularly coils and capacitors, and that the subcircuits can be preferably implemented using integrated insulated-gate field-effect transistor circuits, i.e., so-called MOS technology. This technology is better suited for implementing digital circuits than the so-called bipolar technology.

 The   LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17  is a multisound tv digital sound processing.

It has a DTI.(dti digital transient improvement pertains to a circuit for steepening color-signal transitions in color television receivers or the like particularly in DIGIVISION DIGIT2000 . ) circuit arrangement designed for use in digital color-television receivers or the like and contains for each of the two digital color-difference signals a slope detector to which both a digital signal defining an amplitude threshold value and a digital signal defining a time threshold value are applied. At least one intermediate value occurring during an edge to be steepened is stored, and at the same time value of the steepened edge, it is "inserted" into the latter.

The bandwidth of the color-difference channel is very small compared with the bandwidth of the luminance channel, namely only about 1/5 that of the luminance channel in the television standards now in use. This narrow bandwidth leads to blurred color transitions ("color edging") in case of sudden color-signal changes, e.g., at the edges of the usual color-bar test signal, because, compared with the associated luminance-signal transition, an approximately fivefold duration of the color-signal transition results from the narrow transmission bandwidth.

In the prior circuit arrangement, the relatively slowly rising color-signal edges are steepened by suitably delaying the color-difference signals and the luminance signal and steepening the edges of the color-difference signals at the end of the delay by suitable analog circuits. The color-difference signals and the luminance signal are present and processed in analog form as usual. This circuit arrangement is designed for use in digital color-television receivers or the like and contains for each of the two digital color-difference signals a slope detector to which both a digital signal defining an amplitude threshold value and a digital signal defining a time threshold value are applied. At least one intermediate value occurring during an edge to be steepened is stored, and at the same time value of the steepened edge, it is "inserted" into the latter. This is done by means of memories, switches, output registers, and a sequence controller.

ADVANTAGE - Increased picture sharpness and highly improved signal-to-noise ratio.



It's the last model from LOEWE using the CHASSIS LOEWE C9003 and using ITT DIGIVISION DIGIT2000 chipset. Next models have the LOEWE E3000 DIGITAL CHASSIS which is based on the New ITT DIGIVISION DIGIT3000 chipset. Furthermore, LOEWE, is going to full digital 100HZ Technology in high class style.


The Loewe brand values have been shaped consistently over a long period of time. It all began in Berlin in 1923, with the brothers Dr. Siegmund and David Ludwig Loewe. Since then, one principle has always been adhered to: setting new standards with innovation for the senses.

Loewe established an impressive level of quality as early as 1931, with the first public television transmission worldwide. Loewe has been producing quality made in Germany at its location in Kronach since 1948. In the last 20 years, in addition to the Art 1 from 1985 becoming a design classic, Loewe has received numerous national and international awards.

Digital Signal Processing DIGVISION ITT in Brief:

 FOR several years now the use of digital techniques in television has been growing. A considerable impetus came initially from the need for high -quality Tv standards conversion. The IBA's DICE (Digital Intercontinental Conversion Equipment) standards converter came into operational use in 1972. It's success demonstrated convincingly the advantages of processing video signals in digital form - digital signals are neither phase nor level dependent. The trend since then has been towards the all - digital studio: digital effects generators have been in use for some time, and digital telecines were announced earlier this year. An earlier example of the application of digital techniques to television was the BBC's sound-in-syncs system, in which the sound signal is converted to digital form so that it can be added to the video signal for network distribution. The sound-in-syncs system first came into use in 1969, and is was  widely employed in pay tv systems alongside with video scrambling methods in the 80's.  Digital techniques have already appeared on the domestic TV scene. The teletext signals are digital, and require digital processing. In modern remote control systems the commands from the remote control transmitter are in digital form, and require digital decoding and digital - to -analogue conversion in the receiver before the required control action can be put into effect. Allied to this, digital techniques are used for the more sophisticated channel tuning systems. The basic TV receiver itself continues to use analogue techniques however. Are we about to see major changes here? 
ITT Semiconductors in W. Germany have been working on the application of digital techniques to basic TV receiver signal processing since 1977 with the supervision of the Engineer Micic Ljubomir, and at the recent Berlin Radio Show presented a set of digital chips for processing the video, audio and deflection signals in a TV receiver. The set consists of a' couple of l.s.i. and six v.l.s.i. chips - and by very large scale integration (v.l.s.i.) we're talking about chips that contain some more 200,000 transistors. What are the advantages? 
For the setmaker, there's reduction in the component count and simpler, automated receiver alignment - alignment data is simply fed into a programmable memory in the receiver, which then adjusts itself. Subsequently, the use of feedback enables the set to maintain its performance as it ages. From the user's viewpoint, the advantages are improved performance and the fact that extra features such as picture -within -a -picture (two pictures on the screen at the same time) and still pictures become relatively simple to incorporate. The disadvantage of course is the need for a lot of extra circuitry. Since the received signals remain in analogue form, analogue -to -digital conversion is required before signal processing is undertaken. As the c.r.t. requires analogue drive signals, digital -to -analogue conversion is required prior to the RGB output stages - the situation is somewhat different in the timebase and audio departments, since the line drive is basically digital anyway and class D amplifier techniques can be used in the field and audio output stages. In between the A -D conversion and the various output stages, handling the signals in digital form calls for much more elaborate circuitry - hence those chips with 200,000 or so transistors. The extra circuitry is all incorporated within a handful of chips of course, but the big question is if and when the use of these chips will become an economic proposition, taking into account reduced receiver assembly/setting up costs, compared to the use of the present analogue technology - after all, colour receiver component counts are already very low. With the present digital technology, it's not feasible to convert the signals to digital form at i.f. So conversion takes place following video and sound demodulation. Fig. 1 shows in simple block diagram form the basic video and deflection signal processing arrangement used in the system devised by ITT Semiconductors. Before going into detail, two basic points have to be considered - the rate at which the incoming analogue signals are sampled for conversion to digital form, and the number of digits required for signal coding. Consider the example shown in Fig. 2. At both (a) and (b) the signals are sampled at times Ti, T2 etc. In (a) the signal is changing at a much faster rate than the sampling rate. So very little of the signal information would be present in the samples. In (b) the rate at which the signal is changing is much slower, and since the sampling rate is the same the samples will contain the signal information accurately. In practice, the sampling rate has to be at least twice the bandwidth of the signal being sampled. Once you've got your samples, the next question is how many digits are required for adequate resolution of the signal, i.e. how many steps are required on the vertical (signal level) scale in Fig. 2 The use of a four -digit code, i.e. 0000, 0001 etc., gives 16 possible signal levels. Doubling the number of digits to eight gives 256 signal levels and so on. ITT's experience shows that the luminance signal requires 8 bits (digits), the colour -difference signals require 6 bits, the audio signal requires 12 bits (14 for hi-fi quality) while 13 bits are required for a linear horizontal scan on a 26inch tube. These digital signals are handled as parallel data streams in the subsequent signal processing. Returning to Fig. 1, the A -D and D -A conversion required in the video channel is carried out by a single chip which ITT call the video codec (coder/decoder). A clock pulse generator i.c. is required to produce the various pulse trains necessary for the digital signal processing, and a control i.c. is used to act as a computer for the whole digital system and also to provide interfacing to enable the external controls (brightness, volume, colour etc.) to produce the desired effects. In addition, the control i.c. incorporates the digital channel selection system. The video codec i.c. uses parallel A-D/D-A conversion, i.e. a string of voltage comparators connected in parallel. This system places a high premium on the number of bits used to code the signal in digital form, so ITT have devised a technique of biasing the converter to achieve 8 -bit resolution using only 7 bits (the viewer's eye does some averaging on alternate lines, as with Simple PAL, but this time averaging luminance levels). The A -D comparators provide grey -encoded outputs, so the first stage in the video processor i.c. is a grey -to -binary transcoder. As Fig. 3 shows, the processes carried out in the video processor i.c. then follow the normal practice, though everything's done in digital form. The key to this processing is the use of digital filters. These are clocked at rates up to 18MHz, and provide delays, addition and multiplication. The glass chroma delay line required for PAL decoding in a conventional analogue decoder consists of blocks of RAM (random-access memory) occupying only three square millimeters of chip area each. As an example of the ingenuity of the ITT design, the digital delay line used for chroma signal averaging/separation in the PAL system is used in the NTSC version of the chip as a luminance/chrominance signal separating comb filter. Fig. 4 shows the basic processes carried out in the deflection processor i.c. This employs the sorts of techniques we're becoming used to in the latest generation of sync processor i.c.s. Digital video goes in, and the main outputs consist of a horizontal drive pulse plus drives to the field output and EW modulator circuits. The latter are produced by a pulse -width modulator arrangement, i.e. the sort of thing employed with class D output stages. The necessary gating and blanking pulses are also provided. A further chip provides audio signal processing. One might wonder why the relatively simple audio department calls for this sort of treatment. The W. German networks are already equipping themselves for dual -channel sound however, and the audio processor i.c. contains the circuitry required to sort out the two -carrier sound signals. These chips represent a major step in digitalizing the domestic TV receiver. It seems likely that some enterprising setmaker will in due course announce a "digital TV set". The interesting point then will be whether the chip yields, and the chip prices as production increases, will eventually make it worthwhile for all setmakers to follow this path (in 1984).

One more comment about digital in 2000..............

Over the years we have learnt that one of the most important things in video/ TV technology is selecting the best system to use. We have also seen how difficult this can be. Prior to the start of the colour TV era in Europe there was an great to-do about the best system to adopt. The US NTSC system seemed an obvious choice to start with. It had been proved in use, and refine- ments had been devised. But alternative, better solutions were proposed - PAL and Secam. PAL proved to be a great success, in fact a good choice. 

The French Secam system seems to have worked just as well. Apart from the video tape battles of the Seventies, the next really big debate concerned digital TV. When it came to digital terrestrial TV (DTT), Europe and the USA again adopted different standards. 

One major difference is the modulation system used for transmission. Coded orthogonal frequency   division multiplexing (COFDM) was selected for the European DVB system, while in the USA a system called 8VSB was adopted. COFDM uses quadrature amplitude modulation of a number of orthogonal carriers that are spread across the channel bandwidth. Because of their number, each carrier has a relatively low bit rate. 

The main advantage of the system is its excellent behaviour under multipath reception conditions. 8VSB represents a rather older,  pre phase modulation technoogy: eight  state amplitude modulation of a single carrier, with a vestigial sideband. The decision on the US system was assigned to the Advanced Television Systems Committee (ATSC), reporting to the FCC. The system it proposed was approved by the FCC on December 26th, 1996. The curious date might suggest that there had been a certain amount of politicking. In fact there had been an almighty row between the TV and computer industries about the video standard to adopt, the two fearing that one or other would gain an advantage as the technologies converged. It was 'resolved' by adopting a sort of   "open standard"  we are talking about resolution and scanning standards here - the idea apparently being that the technology would somehow sort itself out.

 There seems to have been rather less concern about the modulation standard. 8VSB was adopted because it was assumed to be able to provide a larger service area than the alternatives, including COFDM, for a given transmitter power. Well, the USA is a very large place! But the US TV industry, or at least some parts of it, is now having second thoughts. Once the FCC had made its decision, there was pressure to get on with digital TV. In early 1998 there were announce- ments about the start of transmissions and broadcasters assured the FCC that DTT would be available in the ten areas of greatest population concentration by May 1999. Rapid advances were expected, with an anticipated analogue TV switch -off in 2006. So far however things have not gone like that. At the end of 1999 some seventy DTI' transmitters were in operation, but Consumer Electronics Manufacturers Association estimates suggest that only some 50,000 sets and 5,000 STBs had been sold.

 There have been many reports of technical problems, in particular with reception in urban and hilly areas and the use of indoor aerials, also with video/audio sync and other matters. Poor reception with indoor aerials in urban conditions is of particular concern: that's how much of the population receives its TV. The UK was the first European country to start DTI', in late 1998 - at much the same time as in the USA. The contrast is striking. ONdigital had signed up well over 500,000 subscribers by the end of 1999, a much higher proportion of viewers than in the USA. Free STBs have played a part of course, but it's notable that DTT 's reception in the UK has been relatively hassle -free. In making this comparison it should also be remembered that the main aim of DTT technology differs in Europe and the USA. 

The main concern in Europe has been to provide additional channels. In the USA it has been to move to HDTV, in particular to provide a successor the NTSC system. There have been plenty of channels in the USA for many a year. For example the DirecTV satellite service started in mid 1994 and offers some 200 channels. Internationally, various countries have been comparing the US and European digital systems. They have overwhelmingly come down in favour of the DVB system. There have been some very damaging assessments of the ATSC standard. The present concern in the US TV industry results from this poor domestic take up and lack of international success. Did the FCC make a boob, in particular in the choice of 8VSB? Following compara- tive tests carried out by Sinclair Broadcasting Group Inc., the company has petitioned the FCC to adopt COFDM as an option in the ATSC standard. Not only did its tests confirm poor reception with indoor aerials: they also established that the greater coverage predicted for 8VSB failed to materialise in practice. Could the USA have two DTT transmission standards? It seems unlikely. It would involve dual standard receivers and non  standardisation of transmitters. In the all important business of system selection, it looks as if the FCC got it wrong.

              ....................................   It is obviously wasteful to duplicate terrestrial TV transmissions in analogue and digital form. Sooner or later transmissions will all be digital, since this is a more efficient use of spectrum space. The question is when? It would suit some to switch off the analogue transmitters as soon as possible. 2006 has been suggested as a time to start, with ana- logue transmissions finally ending in 2010. All very neat and tidy. Whether it will work out in that way is another matter. Strong doubts are already beginning to be aired. 

 The government has, quite properly, laid down conditions to be met before the switch off occurs. Basically that the digital signal coverage should equal that achieved for analogue TV, currently 99.4 per cent of the population, and that digital receiving equipment should be available at an affordable price. The real problem is that there is a difference between a coverage of 99.4 per cent and 99.4 per cent of the population actually having digital receiving equipment. Why should those who are interested in only free - to -air channels go out and buy/rent a digital receiver? It is already becoming evident that this represents a fair chunk of the population. 

The ITC has warned the government that the 2006-2010 timetable is in jeopardy. Peter Rogers, the ITC's chief executive, has said "we need to persuade people only interested in watching free -to -air television to switch to digital. "

Unless we do, there will be no switch - over." Well not quite, because the analogue receivers will eventually wear out and have to be replaced. But that could take a long, long time. Meanwhile many people will expect to be able to continue to watch their usual TV fare using their existing analogue receivers. 

Research carried out by Culture Secretary Chris Smith's department has established that between forty and fifty per cent of the population expects the BBC licence to cover their TV viewing, which means what they get at present in analogue form. A substantial percentage of the population simply isn't interested in going digital. In fact take up of integrated receiver -decoders, as opposed to the free digital set -top boxes, has so far been very slow. 

Of five million TV sets sold in the UK year 1999 , only 10,000 were digital. There are important factors apart from overall coverage and how many people have sets. There is the extension of coverage, which becomes more difficult to achieve eco- nomically as the number of those not covered decreases. There is the problem of reception quality. And there is the question of domestic arrangements and convenience. Extending coverage to the last ten fifteen per cent of the population by means of conventional terrestrial transmitters will be expensive. Mr Smith's department seems to have conceded that other methods of signal delivery may have to be adopted - by satellite, by microwave links or by cable. The latter has of course never been economic where few households are involved. 

The frequency planners have been trying to find ways of increasing coverage even to well populated areas. There are so many areas where problems of one sort or another make the provision of DTT difficult. Satellite TV is the obvious solution. 

The time may well come when it is wondered why anyone bothered with DTT. Signal quality is becoming an increasingly important factor as the digital roll out continues. In areas where the signal is marginal, viewers could experience the extreme irritation of picture break up or complete loss like even todays. This is quite apart from the actual quality of the channel, which depends on the number of bits per second used. There is a maximum number of bits per multiplex, the total being shared by several channels. The fewer the bits, the poorer the picture in terms of definition and rendering. 

There have already been complaints about poor quality. The question of domestic arrangements is one that has not so far received adequate public attention. Most households 2000 nowadays don't have just one TV set that the family watches. They have a main one, probably, almost certainly one or more VCRs, and several other sets around the house to serve various purposes. What 'the percentage of households that have digital TV' should really mean is the percentage willing to replace all this equipment. It will be expensive, and people would not be happy if they were told to throw away their other equipment when they get a single nice new all  singing all dancing widescreen digital TV set. It fact there would be uproar. The move from analogue to digital is not like that from 405 to 625 lines, which went fairly smoothly.

In those days few people had video equipment or a multitude of sets. The transition to digital is not going to be smooth, and the suggestion of a switch off during 2006-2010 already looks totally unrealistic. Unless the government subsidises or gives away digital TV sets - and why should it? - people will expect their existing equipment to continue to be usable.  

So it's likely that analogue TV will be with us for many years yet. But that would be the end of analogue too. 

.............................Indeed...............................

The LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17 is guided via graphics menu on screen through remote intended as  a television system with apparatus for controlling a relatively large number of functions and characteristics with only a relatively small number of control devices.

Television receivers have a relatively large number of functions that are controllable by the user. Typically, these include turning the receiver on and off, selecting channels, setting the volume level and adjusting certain picture characteristics such as brightness, contrast sharpness (sometimes called "peaking"), color level (or saturation) and color tint (or hue) and in television receivers with stereo sound provisions, adjusting certain audio characters such as balance, treble and bass. In addition, with the increased use of digital signal processing and microprocessors, a large number of other control functions have become economically practical. Often a control device is provided for each function or characteristic.

In the case of television receivers with analog signal processing systems, potentiometers are provided for adjusting respective picture and audio characteristics in both increasing and decreasing senses. However, in television receivers with digital signal processing systems it is anticipated that each of these potentiometers may be replaced by two pushbutton switches for digitally causing the respective characteristic to be increased or decreased. Therefore it is anticipated that a digital television receiver will require even more control devices than a comparable analog receiver.

It is desirable for cost and for human engineering reasons to limit the number of user operable control devices. Thus, there has been the desire to provide control apparatus for controlling a large number of functions and characteristics of a television receiver with only a few control devices.

In the past, attempts to make multiple use of switches for controlling various functions in order to limit the number of control devices have been confusing to users. Thus, there exists a need for plural-function and characteristic control apparatus in which multiple use is made of control devices with little or no confusion to users.

In accordance with a feature of the present invention, in a television system, a programming switch and a plurality of switches identified by respective symbols such as numbers, the latter being normally used for channel or television signal source selection, are used to select various functions of a receiver for control. When the programming switch is operated by a user, a character generator produces signals for displaying a list or menu of various receiver control functions, such as the controlling of the picture and audio responses on an image reproducing device associated with the television system. In the menu, each one of the functions is identified by one of the symbols associated with the signal source selection switches. Thereafter, a particular one of the functions displayed on the menu can be selected for control by operation of the corresponding signal source selection switch.

In accordance with another aspect of the invention, after a particular function has been selected for control, a list or menu of characteristics of the selected function, such as brightness, contrast, sharpness, color level and color tint characteristics of the picture response is caused to be displayed. In the menu, each of the functions is identified by one of the symbols associated with the signal source selection switches. Thereafter, a particular one of the characteristics displayed on the menu can be selected for adjustment by operation of the corresponding signal source selection switch. After a characteristic has been selected for control, positive and negative sense adjustment switches common to all the characteristics can be operated to adjust the selected characteristic.
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In 2005, Loewe became the leading premium flat screen television provider. It made its breakthrough with the Loewe Individual: the first flat screen television with individualised housing versions, set-up options and inset colours. In 2008, with the Loewe Connect, Loewe heralded a new, digital television age where non-system end devices could be connected to a flat screen television set. One year later, Loewe combined uncompromising ultraslim design with leading state-of-the-art technology in the Reference range. In 2010, Loewe ultimately introduced the Mediacenter, which provides perfect entertainment networking throughout the home. Another step towards the future.

Loewe AG (pronounced [ˈløːvə]) is the parent company of the German Loewe group. The Loewe group develops, manufactures and sells a wide variety of electronic, electrical and mechanical products and systems, and specialises in the field of consumer and communication technology. The company was founded in Berlin in 1923 by brothers Siegmund and David L. Loewe. The company has its headquarters and sole production facilities in Kronach, Franconia. Today, the range has expanded to include televisions, Blu-ray players, DVD recorders, hard disk recorders, multiroom systems, speakers and racks. The trend is shifting from individual products to complete home entertainment systems. Loewe AG is also represented internationally by sales partners and subsidiaries. These include subsidiaries in the Benelux countries, France, Italy, Austria and the UK. There are exclusive Loewe Galeries acting as flagship stores in many cities around the world, including Madrid, London, Paris, Amsterdam, Rome, Copenhagen, Vienna, Moscow and Hong Kong.


LOEWE Company history
It all began in 1923 in Berlin, when Dr Siegmund Loewe and his brother David Ludwig Loewe established a radio manufacturing company called Radiofrequenz GmbH. Their work with the young physicist Manfred von Ardenne in 1926 led to the development of the triple tube, which was first used in the Loewe OE333 radio receiver. This tube prompted Loewe’s multi-tube production and is today lauded as the world’s first integrated circuit.

Television development began at Loewe in 1929. The company worked together with British television pioneer John Logie Baird. In 1931, Manfred von Ardenne presented the world’s first fully electronic television to the public on the Loewe stand at the 8th Berlin Radio Show.

When Hitler came to power in Germany, Siegmund Loewe had to emigrate to the USA in 1938, where he developed friendship with yet another forced emigrant, Albert Einstein.

In 1949, Siegmund Loewe regained possession of company property and took over as chairman of the supervisory board. In the 1950s, Loewe began producing the Optaphon, the first cassette tape recorder, and manufacturing televisions in Kronach. 1961 saw the first European video recorder, the Optacord 500, enter mass production.

In 1962, the family company tradition ended with the death of Siegmund Loewe. Subsidiaries of the Philips group took over the majority of shares. Under this management, which continued until 1985, the company increasingly specialised in the development and production of televisions.

In 1963, the first portable television, Loewe Optaport, was launched. It had a 25cm screen and built-in FM radio. The first Loewe colour televisions were launched along with the introduction of colour television in Germany. Loewe revolutionised television production in 1979 with a fully integrated chassis (everything on a single board). The first European stereo television followed in 1981.

In 1985, management made Loewe a privately owned company again after Philips sold its shares. In the same year, Loewe created the Art 1, a new generation of TVs with a focus on design.

The CS1 represented another international first in 1995 as the world’s first fully recyclable television. At this time, the course was also set for systematic further development as a multimedia specialist.

1998 marked two more milestones in the company history: the launch of the Xelos @ media, the first television with internet access, and that of the Spheros, the first Loewe flat-screen television. In the following year, Loewe AG became a publicly listed company.

With the Individual, the first flat-screen TV with individual housing options, set-up solutions and inset colours, Loewe took a decisive step and became a premium flat-screen TV manufacturer.

Loewe Connect, the world's first smart TV with fully integrated network capability for wireless access to picture, music and video files on a computer or external hard drive followed in 2008.

LED technology was adopted at Loewe in 2010 in the new Individual. In the following year, Loewe introduced 3D picture display to its Individual range.



01.07.2019 With Loewe, it's over now, here is why..............

The plant in Kronach remains largely deserted from this Monday on: The Upper Franconian TV manufacturer Loewe ceases operations. Most of the more than 400 employees no longer show up for work.

Loewe has been in a crisis for years and now, at least for the time being, the production of televisions in Kronach, Upper Franconia, has come to an end. On Monday, the bankrupt manufacturer with a long tradition ceases operations. The majority of the more than 400 employees are released from work and do not have to come to work. According to the provisional insolvency administrator Rüdiger Weiß, only a core team of ten to fifteen employees remains.

The remaining few employees will continue to look for a rescuing investor in the coming months. One of the most urgent tasks for the insolvency administrator and the Loewe works council is now to negotiate a social plan for the workforce. According to Weiß, he hopes to be able to conclude this by mid-July.

Although the employees are currently released from their duties and no longer receive a salary from Loewe, no one has been dismissed so far. This can only be done after an agreement has been reached on a social plan and a reconciliation of interests. According to Weiß, if no investor is found, the employment contracts could be kept until the end of October at the latest.

Dispute with IG Metall

According to the insolvency administrator's assessment, it will take that long even in the event of another rescue until there is clarity. "We expect the investor process to take another four months," said Weiß. "We will do everything we can to find someone, there have already been initial discussions with investors.

For Loewe, this is the second crisis in a few years to threaten its very existence. "Loewe has been running a loss-making business for years," said Weiß. "Everyone in the company agrees that the compensation structure is not appropriate. To cover personnel costs alone, annual sales of EUR 150 million would be required; for a black zero, we would need sales of EUR 180 million. In fact, it was 120 million in the end."

However, there are fierce disputes with the trade union. The Bavarian IG Metall district manager Johann Horn accuses the British investment company Riverrock of deliberately refusing Loewe new loans. There is some evidence that "the financial investor Riverrock is waiting until Loewe has finally bled out, only to earn money with the ruins of the company afterwards," Horn recently said. In addition, he pointed out that the investor wanted to implement such drastic wage cuts and worse working conditions.

Postbank plays an important role

According to IG Metall, Riverrock has kept Loewe afloat in the past with a double-digit million euro loan, but has now refused a new loan. The former management has also pledged the Loewe brand name to Riverrock.

The preliminary insolvency administrator rejects these accusations: "I cannot understand the criticism of IG Metall," said Weiß. In the presence of the union, all possible models for restructuring had been agreed. "We needed EUR 5.5 million to continue operations until the end of the year and a further EUR 3.4 million for a qualification and employment company for all employees.

According to Weiß, Riverrock was willing to finance this company - but made it dependent on Postbank's decision to take over Loewes' outstanding debts, to pay them on behalf of Loewes and to collect them from customers. So far, Postbank has refused to do so.

LOEWE HISTORY IN GERMAN:
Loewe war und ist immer ein besonderer Betrieb - und bis ins 21. Jahrhundert aktiv und in privatem Besitz. Nicht nur «das erste IC», die Röhre 3NF ist da zu erwähnen, sondern auch die Mitentwicklung des elektronischen Fernsehens in Deutschland.

1923: Radiofrequenz-GmbH und Loewe-Audion GmbH, Berlin-Friedenau;
1926: Aktiengesellschaft D.S. Loewe, Berlin-Steglitz;
1930: Radio-Aktien-Gesellschaft Dr. S. Loewe;
1933 (nach): Löwe-Radio AG;
1942: Opta-Radio AG;
1949: Loewe-Opta AG;
1965: Loewe Opta GmbH, Kronach.
Radios: 1923 bis 1926, Loewe 1927 bis 1978. TV-Fabrikation danach.


Nach Studium der Physik und Elektrotechnik promoviert Siegmund Loewe (Berlin 6.11.1885-28.5.1962 USA) unter Max Wien mit magna cum laude zum Dr. phil. Er tritt bei der Firma Telefunken ein und wechselt 1915 zur Firma Huth, wo er die Leitung der Laboratorien und der Patentabteilung übernimmt. 1918 mietet Loewe in Berlin SW61 eine 7-Zimmer-Wohnung und erstellt mit einer kleinen Entwicklungsgruppe einen Telefonie-Röhrensender, dessen Sendungen in dem nicht weit entfernten Haus des Scherl-Verlages von Otto Kappelmayer zu empfangen sind. Um seine Kenntnisse zu erweitern, begibt sich Loewe in die USA. Einen ausführlichen Bericht von und über Loewe finden Sie in [1-99], woraus Sie erkennen können, dass Loewe das treibende Element für den Rundfunk in Deutschland war. Wie er gegen den Monopolanspruch von Telefunken/Lorenz/Huth (Funkkartell «Rundfunk GmbH») kämpfte und weitere Details finden Sie in [6-121].

Nach seiner Rückkehr aus den USA wird das Versuchslabor von Loewe zum Kristallisationspunkt der jungen Funktechnik. Im Dezember 1921 erhält Loewe Besuch von Lee de Forest, und sie verbessern gemeinsam Röhren. 1921 entstehen auch zwei grundlegende Patente für den Konus-Lautsprecher. Loewe eröffnet ein zweites Laboratorium und gründet 1923 die Loewe-Audion-GmbH für die Herstellung von Radioröhren sowie die Radiosender GmbH.

Im Dezember 1921 lernt der Realschüler Manfred von Ardenne den Radiopionier Loewe in einem Elektrikergeschäft kennen und ist darauf häufiger Gast in den Laboratorien von Loewe. Ein Autor schreibt, dass Loewe zum «Ziehvater» des jungen von Ardenne wird und er in der Familie aufgenommen ist, doch von Ardenne beschreibt dies in seinem Buch «Eine glückliche Jugend im Zeichen der Technik» (DDR) nicht.

Die wahrscheinlich 1923 gegründete Loewe Radio GmbH führt der jüngste Loewe-Bruder Bernhard. Das D bei D.S. Loewe steht für den älteren Bruder, David (Teilhaber).

Radiofrequenz GmbH und Loewe-Audion GmbH (1923-27):
Am 22.1.23 erwirbt Dr. Siegmund Loewe die seit 1918/19 bestehende Mechanische Werkstatt Grüttner & Lütgert in Berlin-Friedenau und gründet die Radiofrequenz GmbH. Die ersten Geräte sind für den Export bestimmt. Davon sind mir die Typen EA51, EA52 und EA54 bekannt. EA steht für «Empfangs-Apparat».

Im Jahr darauf stellt der Betrieb die Ziffer 9 vor die laufende Nummer. Der Sprung von EA958 auf EA980 deutet auf andere Artikel hin (z.B. Trichterlautsprecher und kombinierte Geräte etc.). Nachher ist keine Nummernsystematik mehr zu erkennen, ausser den Buchstabenkombinationen wie OE (Orts-Empfänger), FE (Fern-Empfänger), KV (KW-Vorsetzer), RO (Rückkopplungs-Ortsempfänger) etc.
1927 gibt Loewe den Namen Radiofrequenz auf und verwendet seinen eigenen Namen. Die drei Geräte OE333, 2H3N und NVG gibt es unter beiden Namen, da sie Loewe 1927/28 ohne neue Modelle weiter produziert. Mehr als eine Million dieser Geräte lassen sich zum Stückpreis von 39.50 RM verkaufen, und die Tagesproduktion erreicht zeitweise 2000 Einheiten.

Im Oktober 1923 gründet Loewe eine weitere Gesellschaft zur Herstellung von Rundfunkröhren mit dem Namen Loewe-Audion GmbH, ebenfalls an der Niedstrasse 5 in Berlin-Friedenau gelegen. Zuerst entstehen dort Wolfram-, dann Thoriumröhren als «Sparröhren». Im September 1924 meldet Loewe die grundlegenden Patente zur Dreifachröhre mit integrierten Bauteilen an, die 1926 als 3NF mit dem «Loewe Ortsempfänger OE333» einen legendären Ruf erreicht.

Loewe, Löwe, Opta, Loewe-Opta
Die Schrift «Loewe-Story» aus dem Hause Loewe-Opta zeigt die Abbildung eines «Detektor-Empfängers» mit zwei Steckspulen, der angeblich zur Eröffnung des Rundfunks bereitstand. Es ist aber ein umfunktionierter Sperrkreis für den Empfänger 2H3N, Baujahr 1927, was auch aus dem Firmenschild mit «Berlin-Steglitz» hervorgeht.

1926 entsteht die Aktiengesellschaft D.S. Loewe, Berlin-Steglitz. Als zweites Gerät unter der neuen Marke Loewe bzw. Loewe Radio gilt der auf der Funkausstellung im September 1926 gezeigte Fernempfänger 2H3N zu RM 150. Auch Lautsprecherboxen mit Loewe-Konus-Lautsprecher und Stoffbezug im «Südsee-look» sind nun erhältlich. Wegen der steigenden Anzahl Rundfunksender treten Trennschärfeprobleme auf, so dass die Dreifachröhre für den Einbezug einer Rückkopplung einen siebten Anschluss erhält. Diese «3NF7» baut Loewe ab 1928 in alle OE333, 2H3N und in das dritte Gerät, den RO433 ein. Die elektrische Schallplatten-Abtastdose LR150 erregt Aufsehen; Gewicht 260 g! Die Dose verlangt einen Abspielwinkel von 55 Grad. Die 3NF gibt es nun auch mit Oxydkathode als 3NFB mit einem Verbrauch von 0,13 statt 0,34 A Heizstrom - zudem beträgt die Verstärkung etwa das Doppelte. Weitere Details zu Firmengründungen von Loewe siehe [638967]. Es sind dies z.B. die Eudarit-Pressgut GmbH für Bakelitgehäuse etc. und die Ortophon-Apparatebau GmbH für den Lautsprecherbau.

1929 bringen die Loewe-Firmen den «Vollnetzanschluss-Empfänger R533» heraus, der mit einer nochmals verbesserten Dreifachröhre, der 3NFW mit indirekter Heizung, ausgestattet ist. 1929 entsteht Loewe's Berliner-Radio-Handels-Aktiengesellschaft. Die Baird Television Company Ltd., London, bietet Loewe die Auswertung und Entwicklung ihrer Schutzrechte und Entwicklungsarbeiten auf dem Fernsehgebiet in Deutschland an. Da dieses Angebot die finanziellen Möglichkeiten von Loewe übersteigt, regt Dr. Loewe eine Beteiligung von Zeiss Ikon, Dresden, und Robert Bosch, Stuttgart, an. Es kommt Mitte 1929 zur Gründung der Fernseh-AG in Berlin, die 1939 im Firmenverband Robert Bosch aufgeht.

1930 fasst Loewe verschiedene seiner Firmen unter dem Namen Radio-Aktien-Gesellschaft Dr. S. Loewe zusammen und mit dem EB100W (1931 EB100G) beginnt die Reihe der Empfänger mit integriertem Lautsprecher.

Im Auftrag der Loewe-Firmen bringt von Ardenne aus seinem eigenen Labor 1930 erste brauchbare Vorschläge zur Helligkeitssteuerung, um auf einem Bildschirm ein gut modulierbares Bildraster zu schreiben. Meine gasgefüllte Braun'sche Röhre aus dem Labor von Ardenne zeugt für die Forschung um 1926.

Auch auf der Senderseite entwickelt Loewe elektronische Medien auf der Grundlage des «Flying-spot-Abtasters», um Filme elektronisch übertragen zu können. Am 25.4.31 veranstalten Dr. S. Loewe und M. von Ardenne in den Lichterfelder-Laboratorien eine Vorführung vor der Fachpresse. Bald darauf kann Loewe die Qualität der mechanischen Systeme erreichen und übertreffen. Siehe [1-127f]. 1932 geht von Ardenne eigene Wege. 1933, ein Jahr vor den Mitbewerbern, erkennt Dr. Loewe die Notwendigkeit von Allstrom-Apparaten und bringt den 1-Kreis-Empfänger «Edda» auf den Markt. (Ganz so richtig ist das nicht: zumindest Emud kommt 1931 mit «Allstrom», EE). Zu der Zeit halten sich Wohnungen mit Gleich- bzw. Wechselstrom etwa die Waage und eine Familie, die umzieht, kann den transformatorlosen Apparat weiterverwenden. Der Apparat führt die Allstrom-Dreifachröhre WD33. Das Allstromkonzept führt Loewe auch für Mehrkreis- und Superhet-Empfänger mit den Röhren WG34, WG35 und WG36 fort.

Auf dem in England bestellten Sattelschlepper mit einer Fernseh-Sendereinrichtung steht anlässlich der Premiere vom Juli 1934 in London gross der Namenszug Radio A.G. D.S. Loewe. Das Regime in Deutschland lässt die Firma jedoch bald in Löwe-Radio AG umtaufen und 1942 in Opta-Radio AG. Loewe wandert 1936 in die USA aus und gründet dort die Loewe Radio Inc. Er hat 1938 aus dem Vorstand in Deutschland auszuscheiden.

1941-44 fertigen die Opta-Betriebe ausschliesslich Rüstungsgüter; Opta-Radios sind dann Fremdtypen [638966-19]. Man gliedert Grassman in den Opta-Betrieb ein. Es entstehen Auslagerungsbetriebe, z.B. in Oberlungwitz in Sachsen. In Berlin-Weissensee entsteht während des Krieges ein Betrieb für Röhrenbau [DRM94].

Noch im März 1945 verlagert das Unternehmen eine wichtige Kriegsfertigung nach Küps bei Kronach. Dies ist die Keimzelle der neuen Firma, denn 1948 kann S. Loewe seine Wiedergutmachungsansprüche durchsetzen und erhält das Sagen beim demontierten Hauptwerk in Berlin und der Auslagerungsstätte in Küps bei Kronach. In Küps fabriziert Loewe ab 1946. Gemäss «Loewe-Story» gibt es vor November 1947 den «Kronach», wahrscheinlich 547W, in einer Auflage von zwei Geräten pro Tag. Ein getrenntes Werk in Düsseldorf-Heerdt offeriert als Firma Opta-Spezial GmbH von 1950 bis 1954 Opta-Spezial-Radios [6-124]. Konsul Bruno Pieper wirkt als Generaldirektor.

Jedenfalls: Auf der Leipziger Messe von 1947 sind wieder Loewe-Entwicklungen zu sehen. Die Firma erzeugt 1950 mit dem «Optaphon» das erste deutsche Kassetten-Tonbandgerät. 1961 ist Loewe mit dem «Optacord 500», einer für den privaten Gebrauch konzipierten Video-Anlage, führend beim Bildschirmtext und baut vor allem modernste TV-Empfänger - ein Steckenpferd von Dr. S. Loewe. Er stirbt 1962.

Bis 1978 fertigt die Firma Radios in Berlin, löst diesen Betrieb aber auf. Der Mitarbeiterbestand bei Loewe beträgt Ende der 80er Jahre ca. 1500. Die Loewe Opta GmbH, Kronach, gehört in den 90er Jahren zu 51,9 % der Management GBR (Gesellschaft leitender Mitarbeiter der GmbH) und zu 48,1 % zu Matsushita (Panasonic), wobei eine gute gegenseitige Befruchtung für das Hauptprodukt, TV, zum Tragen kommt.

Loewe in Ostdeutschland:
Opta Leipzig, ab 1950 VEB Stern-Radio Leipzig genannt, geht 1952 im VEB Fernmeldewerk Leipzig auf. Die Radioproduktion endet 1950/51.

Nach dem Krieg versuchen Loewe-Mitarbeiter des Zweigwerkes in Oberlungwitz in Sachsen, Maschinen und Vorrichtungen nach West-Berlin zu transportieren, doch die Sowjets verlangen, dass diese Güter in die Röhrenfabrik Berlin-Weissensee gelangen.

Dieser Loewe-Betrieb arbeitet mit der Röhrenfabrik in Berlin.

Loewe hat auch in anderen Ländern Produktionsstätten, so z.B. in Grossbritannien. Vor allem aber auch Handelsniederlassungen, wie Loewe Radio S.A., 3 quai de Willebroeck, Bruxelles (adress in 1932).

Literature

• 75 Jahre Loewe (1923-1998). Und die Zukunft geht weiter, author's edition 1998
• Kilian J.L. Steiner: Ortsempfänger, Volksfernseher und Optaphon. Die Entwicklung der deutschen Radio- und Fernsehindustrie und das Unternehmen Loewe 1923-1962. Klartext Verlag, Essen 2005, ISBN 978-3-89861-492-4
• Frank Keuper, Jürgen Kindervater, Heiko Dertinger, Andreas Heim (Hrsg.): Das Diktat der Markenführung. 11 Thesen zur nachhaltigen Markenführung und -implementierung. Mit einem umfassenden Fallbeispiel der Loewe AG, Gabler Fachverlage, Wiesbaden 2009, ISBN 978-3-8349-0852-0

References

• "Loewe klang 5 active speaker - Winner - Entertainment - German Design Award". www.german-design-award.com (in German). Retrieved 2017-09-13.
• https://www.loewe.tv/de/legal/impressum
• 
  
• "German technology manufacturer Loewe declares bankruptcy"
• 
  
• Loewe AG: self-administration insolvency, a corporate press-release
• 
  
• "Investor consortium to rescue high-end TV maker Loewe". Deutsche Welle. Retrieved 17 January 2014.
• 
  
• "Münchener Investor übernimmt Loewe". Handelsblatt. Retrieved 6 January 2015.
• 
  
• "German Design Award Winners".
•  
•  

Einzelnachweise

loewe.tv: Impressum
Loewe bild 7 - Gold - Entertainment - German Design Award. Abgerufen am 9. Oktober 2017.

http://www.nordbayerischer-kurier.de/nachrichten/loewe-gliedert-markenrechte-aus_627658

NDR: Manfred von Ardenne - Herr des Fernsehens. Abgerufen am 9. Oktober 2017.

NDR: Manfred von Ardenne - Herr des Fernsehens. Abgerufen am 9. Oktober 2017.

Loewe. Abgerufen am 13. September 2017 (englisch).

Radioapparate. In: Berliner Adreßbuch, 1924, Teil 2, S. 475.

Kilian J. L. Steiner: Die „Arisierung“ der Radioaktiengesellschaft D. S. Loewe in Berlin-Steglitz. In: Christof Biggeleben u. a.: „Arisierung“ in Berlin. Metropol Verlag, Berlin 2007, ISBN 978-3-938690-55-0, S. 226.

radiomuseum-bocket: Der OE333 Ortsempfänger. Abgerufen am 8. November 2016.

radiomuseum.org: Ortsempfänger OE333. Abgerufen am 28. Januar 2016.

radiomuseum.org: Röhre 3NF. Abgerufen am 28. Januar 2016.

Die Loewe-Röhre 3NFB – Analyse einer Mehrfachröhre. (PDF; 170 kB)

Kilian J. L. Steiner: Die „Arisierung“ der Radioaktiengesellschaft D. S. Loewe in Berlin-Steglitz. In: Christof Biggeleben u. a.: „Arisierung“ in Berlin. Metropol Verlag, Berlin 2007, ISBN 978-3-938690-55-0, S. 226.

Kilian J. L. Steiner: Die „Arisierung“ der Radioaktiengesellschaft D. S. Loewe in Berlin-Steglitz. In: Christof Biggeleben u. a.: „Arisierung“ in Berlin. Metropol Verlag, Berlin 2007, ISBN 978-3-938690-55-0, S. 226.

Joachim Hofer: Loewe will leben. In: Handelsblatt. 17. Juli 2013, S. 16 f.

Letzte Chance für Loewe. In: Handelsblatt. 17. Juli 2013, S. 1.

Loewe hofft auf den reichen Retter. Handelsblatt, 16. Juli 2013, abgerufen am 16. Juli 2013.

Loewe schwört trotz Krise auf Luxus-Geschäftsmodell. inFranken.de, 31. Juli 2013, abgerufen am 1. August 2013.

Loewe: Partner kommt aus China. inFranken.de, 31. Juli 2013, abgerufen am 1. August 2013.

Loewe: Kapitalmaßnahmen auf den Weg gebracht. (Nicht mehr online verfügbar.) Loewe AG, 7. August 2013, archiviert vom Original am 5. Oktober 2013; abgerufen am 1. September 2013.  Info: Der Archivlink wurde automatisch eingesetzt und noch nicht geprüft. Bitte prüfe Original- und Archivlink gemäß Anleitung und entferne dann diesen Hinweis.

Restrukturierungsprozess vor dem Abschluss. (Nicht mehr online verfügbar.) Loewe AG, 16. September 2013, archiviert vom Original am 26. September 2013; abgerufen am 17. September 2013.  Info: Der Archivlink wurde automatisch eingesetzt und noch nicht geprüft. Bitte prüfe Original- und Archivlink gemäß Anleitung und entferne dann diesen Hinweis.

TV-Hersteller Loewe meldet Insolvenz an (1. Oktober 2013)

Loewe AG: Insolvenzverfahren in Eigenverwaltung bestätigt. (Memento des Originals vom 4. Oktober 2013 im Internet Archive)  Info: Der Archivlink wurde automatisch eingesetzt und noch nicht geprüft. Bitte prüfe Original- und Archivlink gemäß Anleitung und entferne dann diesen Hinweis. Ad-hoc-Meldung auf: corporate.loewe.tv, 1. Oktober 2013.

TV-Hersteller in der Krise: Loewe meldet Insolvenz an. auf: spiegel.de, 1. Oktober 2013.

Bevollmächtigter gibt sich für Loewe optimistisch. FAZ.net. 13. Oktober 2013

Insolventer TV-Hersteller: Loewe-Käufer machen Rückzieher. Spiegel Online, 24. Februar 2014, abgerufen am 24. Februar 2014.

Stargate Capital übernimmt Loewe, Handelsblatt, am 21. März 2014

Neue Hoffnung für Loewe: Finanzinvestor übernimmt TV-Gerätebauer. In: Heise Online. 22. März 2014, abgerufen am 23. März 2014.

Loewe findet neuen Investor. In: Süddeutsche Zeitung. 22. März 2014, abgerufen am 23. März 2014.

Andreas Wilkens: Loewe-Rettung in trockenen Tüchern. 9. April 2014, abgerufen am 9. April 2014.

Loewe: 2016 noch kein Gewinn | Nordbayerischer Kurier. Abgerufen am 28. August 2017.

Loewe. Abgerufen am 9. Oktober 2017 (englisch).

LOEWE CALIDA 72 Super Flatline Art. Nr. 52460 L17 CHASSIS 110C93 (C9003) INTERNAL VIEW.

It's the last model from LOEWE using the CHASSIS LOEWE C9003 and using ITT DIGIVISION DIGIT2000 chipset.

Next models have the LOEWE E3000 DIGITAL CHASSIS which is based on the New ITT DIGIVISION DIGIT3000 chipset. Furthermore, LOEWE, is going to full digital 100HZ Technology in high class style.

For a complete technology reference of the Digivision ITT DIGIT2000 you can Read HERE.

This is the First LOEWE CHASSIS using the ITT CCU3000 Controller, the previous were using the ITT CCU2000 type mounted outside the chassis on other PCB.
The ITT CCU3000 is mounted on the unit here above photographed toghether with the Firmware ROM and the Teletext Processing Unit TPU2735.

This chassis is derived from the C9000 series which shares the layout.
The C9000 series is the first digital chassis developed by LOEWE around 1987 employing the ITT DIGIT2000 technology and was fitted in models like LOEWE ART1 and STUDIO which both you can see HERE soon or later.

These were high reliable and durable. Main fault was the EHT transformer which in some circumstances corrupts the data EEPROM which needs a reprogramming and/or a replacement.

The LOEWE C9003 Is employing the ACVP2205 (Adaptive Combifilter Video Processing) instead of the PVPU2203.

Technology overview:ACVP2205 (Adaptive Combifilter Video Processing)
n a chroma control circuit for a digital television receiver, the system clock lies in the range of four-times the chrominance-subcarrier frequency. The originally received color-burst signal is locked in frequency and phase to the system clock by means of an all-digital phase-locked loop. The phase-difference angle between the color-burst signal and the system clock appears as a sine or cosine value in the two standard color-difference signals of the chrominance demodulator during the reception of the color-burst signal. One of the standard color-difference signals, the B-Y signal, is fed through a horizontal-frequency-suppressing loop filter to a digital oscillator. The latter determines the speed of rotation of a hue adjustment angle rotating at approximately constant angular speed. The respective sine and cosine values of the hue adjustment angle are read as data values from first and second read-only memories, respectively, and are fed to the sine and cosine inputs of a hue adjuster in a calculating stage which derives the color-burst signal and the chrominance signal.

A comb filter arrangement operating at a reduced data rate is provided, which requires comparably fewer storage locations than previous arrangements. A digitized composite video signal of a given codeword rate is applied to a bandpass filter, which produces a filtered signal restricted to a portion of the passband of the composite video signal. The filtered signal is then subsampled at a rate which satisfies the Nyquist criterion for information of the restricted passband. Codewords, now at a reduced data rate, are applied to a one-H delay line, and delayed and undelayed signals are combined to produce a first comb-filtered signal. The first comb-filtered signal is then applied to an interpolator, which provides a sequence of codewords at the codeword rate of the original digitized composite video signal. This sequence of codewords is then combined with the codewords of the composite video signal to produce a second comb-filtered signal.
This invention relates to signal separation systems and, in particular, to a comb filter arrangement for separating the luminance and chrominance components of a digitized video signal at a reduced data rate.

Conventional television broadcast systems are arranged so that much of the brightness (luminance) information contained in an image is represented by signal frequencies which are concentrated about integer multiples of the horizontal linescanning frequency. Color (chrominance) information is encoded and inserted in a portion of the luminance signal spectrum around frequencies which lie halfway between the multiples of the line scanning frequency (i.e., at odd multiples of one-half theline scanning frequency).

Chrominance and luminance information can be separated by appropriately combing the composite signal spectrum. Known combing arrangements take advantage of the fact that the odd multiple relationship between chrominance signal components andhalf the line scanning frequency causes the chrominance signal components for corresponding image areas on successive lines to be 180.degree. out of phase with each other. Luminance signal components for corresponding image areas on successive linesare substantially in phase with each other.

In a comb filter system, one or more replicas of the composite image-representative signal are produced which are time delayed from each other by at least one line scanning interval (a so-called one-H delay). The signals from one line are addedto signals from a preceding line, resulting in the cancellation of the chrominance components, while reinforcing the luminance components. By subtracting the signals of two successive lines (e.g., by inverting the signals of one line and then combiningthe two), the luminance components are cancelled while the chrominance components are reinforced. Thus, the luminance and chrominance signals may be mutually combed and thereby may be separated advantageously.

The composite video signal may be comb filtered in an analog form, a sampled data form, or a digital form. Comb filters using analog signal glass delay lines for the (approximately) one-H delay lines are commonly employed in PAL-type receiversto separate the red and blue color difference signals, taking advantage of the one-quarter line frequency offset of the interlacing of the two signals. An example of a comb filter system for a sampled data signal is shown in U.S. Pat. No. 4,096,516,in which the delay line comprises a 6821/2 stage charge-coupled device (CCD) delay line which shifts signal samples from stage to stage at a 10.7 MHz rate to achieve a one-H delay. The article "Digital Television Image Enhancement" by John P. Rossi,published in Volume 84 of the Journal of the Society of Motion Picture and Television Engineers (1974) beginning at page 37 shows a digital comb filter in which the one-H delay is provided by a digital storage medium for 682 codewords which is accessedat a 10.7 MHz rate.

In the CCD delay line described in the above-referenced U.S. patent, 6821/2 stages are needed to transfer charge packets related to the analog video signal. But in the digital delay line described in the Rossi article, the video signal is inthe form of eight-bit digital codewords. This arrangement requires the use of eight storage locations for each of the 682 codewords in a horizontal line, or a storage medium for 5,456 bits. Moreover, this delay line is only of sufficient size for asystem in which an NTSC color video signal is sampled at a rate of three times per subcarrier cycle (i.e., using a 10.738635 MHz sampling signal). A frequently discussed sampling frequency for digitizing the analog video signal is 14.3181818 MHz, orfour times the color subcarrier frequency. A one-H digital delay line operating at this frequency requires storage for 910 codewords which, at eight bits per codeword, requires a total of 7280 storage locations. Since a storage medium of this capacityis difficult to fabricate economically, it is desirable to provide a digital comb filter system which requires fewer storage locations.

In accordance with the principles of the present invention, a comb filter arrangement operating at a reduced data rate is provided, which requires comparably fewer storage locations than previous arrangements. A digitized composite video signalof a given codeword rate is applied to a bandpass filter, which produces a filtered signal restricted to a portion of the passband of the composite video signal. The filtered signal is then subsampled at a rate which satisfies the Nyquist criterion forinformation of the restricted passband. Codewords, now at a reduced data rate, are applied to a one-H delay line, and delayed and undelayed signals are combined to produce a first comb-filtered signal. The first comb-filtered signal is then applied toan interpolator, which provides a sequence of codewords at the codeword rate of the original digitized composite video signal. This sequence of codewords is then combined with the codewords of the composite video signal to produce a second comb-filteredsignal.

The invention pertains to a chroma control circuit for a digital television receiver.

A chroma control circuit of this kind is described in an INTERMETALL Data Book entitled "Digit 2000 VLSI Digital TV System", Freiburg/Br., June 1985, pages 163 to 174, which explain the CVPU 2210 NTSC comb-filter video processor. The chroma control circuit according to the aforementioned preambles is contained especially in FIG. 10-2 on page 165, which is described in Section 10.1.4 on page 167 and in Section 10.1.6 on page 168.
In the NTSC and PAL television standards, the hue of a picture element can be represented as an angle-coded signal with respect to a transmitter reference system. The different phase angles from 0° to 360° correspond to hues assigned thereto, the zero reference phase being the zero phase of one of the two standard color-difference signals, namely the B-Y signal. The transmitter reference system is the unmodulated chrominance subcarrier, which is suppressed during the horizontal trace period but is transmitted for a short time as a burst signal during the horizontal retrace period, the phase of the burst signal, referred to the B-Y color-difference signal, being
-180° in the case of the NTSC television standard, and
+/-135° in the case of the PAL television standard.
In the prior art chroma circuit, the receiver reference system is the system clock, which has four times the frequency of, and is locked in frequency and phase to, the unmodulated chrominance subcarrier; four successive system-clock pulses, beginning with the zero phase of the B-Y color-difference signal, correspond to the phase angles of 0°, 90°, 180° and 270° of the unmodulated chrominance subcarrier. The latter, which is included in the composite color signal as mentioned above, is fed to the chroma control circuit after the chrominance and luminance components have been separated from the composite color signal by means of the chrominance filter.
In the NTSC and PAL television standards, the zero reference phase of the receiver reference system is the zero phase of the B-Y color-difference signal during the reception of the color burst. In that case, the R-Y color-difference signal is zero, and the phase comparison in the phase-locked loop is very simple.
If this chroma control circuit is to operate correctly, the chrominance subcarrier and the system clock, which has four times the chrominance-subcarrier frequency, must be locked together in frequency and phase. This is accomplished with a phase-locked loop, which causes the system clock to lock with the unmodulated chrominance subcarrier.
During the further development and improvement of this integrated chroma control circuit, the inventors discovered that the action of the phase-locked loop on the frequency and phase of the system clock is disadvantageous. For example, the phase-locked loop requires a voltage-controlled oscillator for the system clock whose deviation from the reference phase during a line period must not exceed 3°. This corresponds to a permissible deviation of the system-clock frequency of only 0.03 per mill from its nominal value if the phase difference at the beginning of the scanned line is zero. Otherwise, the permissible frequency deviation is even smaller. The necessary frequency stability and control accuracy are thus very high, so that tunable crystal oscillators are used for generating the system clock.
In addition, the data resulting from the phase comparison must be fed to the voltage-controlled oscillator, which is a tunable crystal oscillator forming part of a separate monolithic integrated circuit, so that additional terminals and interconnecting leads are required for both integrated circuits.
Another problem arises if such chroma control circuits are used in television receivers with two or more receiving units which present the information from two or more signal sources or television channels on the screen simultaneously. Each of those receiving units requires a separate clock system whose frequency must be synchronized with the frequency of the respective color-burst signal. With the small differences in the frequencies of the various received color-burst signals, interaction of the associated voltage-controlled oscillators is hardly avoidable, which results in interferences on the screen. The greater the lock-in range of the tunable crystal oscillators, the stronger the interaction will be, because the frequency stability of the oscillators decreases with increasing lock-in range.
SUMMARY OF THE INVENTION
Accordingly, one object of the invention is to improve the prior art chroma control circuit in such a way that the system clock need not be locked to four times the frequency of the originally received chrominance subcarrier, so that it can be locked to other system-related signals, such as a fixed-frequency signal, and that the phase-locked loop is an all-digital circuit.
The fundamental idea of the invention is to achieve the correct adjustment of the frequency and phase between the system clock, which forms the receiver reference system, and the color-burst signal not by locking the system clock to four times the frequency and four times the phase of the color-burst signal by means of a voltage-controlled oscillator, i.e., by analog means, as has been done so far, but by leaving the frequency and phase of the system clock unchanged and taking the necessary locking measures on the received color-burst and chrominance signals. The phase of the digitalized burst signal is, therefore, rotated with respect to the zero phase of the receiver reference system purely digitally by means of a phase-locked loop until it is -180° or +/-135° in accordance with the NTSC or PAL television standard, respectively; at the same time, frequency equality is established between the rotated burst signal and the system clock. The necessary correction angle is then applied to the chrominance signal too. In case of large frequency differences between the original received color-burst signal and the system clock, the correction of the chrominance signals during the scanning line must be interpolated.
A special advantage of the invention that one or more chroma control circuits in accordance with the invention can be added to the prior art chroma control circuit to produce a television receiver for multipicture reproduction that has only a single system clock for all receiving systems.
Another important advantage is that the system clock can be synchronized with signals which are locked to the horizontal frequency or a multiple thereof. This offers advantages during operation of a video recorder and in signal processing for picture enhancement as is performed, for example, to obtain a flicker-free television picture.
Finally, the necessary interpolation of the chroma correction during the scanning line is achieved by the invention in an advantageous manner even in case of large frequency differences between the originally received color-burst signal and the system clock.





- SPU2243 Secam Processor Unit
- ACVP2205 Adaptive Digital Combifilter Video Processing
- DTI2223 Digital Transient Improvement
- VCU2136 Video Codec/Decodec Unit
- DPU2553 Deflection Processing Unit

- APU2471 Audio Processing Unit


















- ADC2311 Analog/Digital Converter

















CCU 3000, CCU 3000-I Main System Processor
CCU 3001, CCU 3001-I
MICRONAS INTERMETALL

1. Introduction
The CCU 3000, CCU 3000-I, CCU 3001, CCU 3001-I
are integrated circuits designed in 1.2 mm CMOS
technology, with the exception of CCU 3000, TC18 and
TC19, which is designed in 1 mm CMOS technology. The
CPU contained on the chips is a functionally unchanged
65C02-core, which means that for program development,
systems can be used which are on the market; including
high level language compilers.
The pin numbers mentioned in this data sheet refer to
the 68-pin PLCC package unless otherwise designated.
The CCU 3000-I is described separately in an addendum
on page 66.
1.1. Features of the CCU 3000, CCU 3000-I,
CCU 3001, CCU 3001-I
– CCU 3000 = ROM-less version of the CCU 3001
– 65C02 CPU with max. 8 MHz clock
– 32 kByte internal ROM (CCU 3001 only)
– 1344 internal Bytes RAM with stand-by option
– 51 I/O lines (CCU 3001)
– 26 I/O lines (CCU 3000)
– clock generator with programmable clock frequency
– 8 level interrupt controller
– CCU 3000, CCU 3001:
2 Multimaster IM bus interfaces
– CCU 3000-I, CCU 3001-I: 1I2C/IM bus and
1 Multimaster IM bus interface (see addendum)
– IR-input for software-decoded IR-systems
– on-chip power on, stand-by and clock supervision
logic
– on-chip watchdog
– 3 multifunctional timers
– supports memory banking (external 2MBytes)
– power down signal for external memory
– mask option: EMU mode
– programs can be written in Assembler or in “C”
– CCU 3000 TC 18/19: 1.0 mm CMOS technology, (see
addendum)
– application software available.

Functional Description
2.1. ROM
The chip is equipped with 32 kByte mask-programmable
ROM. The ROM uses up the address space from 8000H
to FFFFH. This ROM can be supplemented or replaced
externally. Only the CCU 3001 has an internal ROM.
2.2. RAM
The RAM area is split into three parts:
– page 0 (address 0 to FFH)
– page 1 (address 100H to 1FFH)
– page 3, 4, 5, 6 (address 300H to 63FH)
Page 0 offers a particularly fast access to the 65C02 and
is therefore very valuable for fast, compact programs.
Page 1 contains the stack and must therefore also have
RAM. The remaining RAM-memory follows in pages 3,
4, 5, 6, as page 2 is reserved as I/O address space. The
RAM can be kept in the stand-by mode via stand-by pin.
2.3. CPU
The CPU core is fully compatible with the 65C02 microprocessor.
However, not all the pins of the 65C02 processor
are accessible for the user outside the chip. One
switch in the control register allows the CPU to be
switched off, so that an external processor can take over
its tasks. This external processor can of course also be
an in-circuit emulator, which makes near-hardware
emulation possible, even though the status and control
lines of the internal CPU are not accessible. If an external
processor is used, all hardware blocks of the chip are
as accessible to it as if it were the internal CPU.
2.4. Clock Generator
An integrated two-pin oscillator generates the clock for
the microcontroller. The frequency created by the oscillator
can be programmed to be reduced with a divider
by the factor 1 ... 255. This enables the user to decrease
the current consumption by the controller by reducing
the working frequency as well as to increase the access
time for the (slower) external memory. This divider contains
the value 4 after a reset, so that the system can also
start with a slow external memory. If the mask-option
OSC is set (EMU version), a switch in the control register
makes it possible to receive the internal clock F2 at
XTAL2. In this case the oscillator must be external and
the clock must be fed to the pin XTAL1. In this way, the
user gets a time reference for internal operations in the
microcomputer. This is especially important with the interrupt
controller. The production version of the CCU
does not have this function!
2.5. PORT 1 to PORT 3, PORT 6 to PORT 8
8 ports belong to the system, of which 5 are 8 bits wide,
one 6 bit, one 4 bit and one 1 bit wide. All port lines of
PORTS 1 to 3 and 6 to 8 can be used as inputs or outputs
independently from each other. One register per port
defines the direction. PORT1 to PORT3 have push-pull
outputs and PORT6 to PORT8 have open drain outputs.
Even a line defined as output can be read, the pin level
being important. This property makes it possible for the
software to find desired and undesired short circuits.
Each port reserves a byte for the direction register and
the data in the I/O page. If the corresponding bit in the
direction register is set to 0, the output mode is switched
on. After a reset, all bits of a direction register are set
to 1. The falling edge of bit 7 of PORT 8 generates interrupts
if the priority of the corresponding interrupt controller
source (7) is not set to 0.
2.6. PORT 4
PORT 4 consists of only one line (LSB, P40). After a reset,
PORT 4 operates as an input only. As soon as PORT
4 is written for the first time, it is switched to output mode
(push-pull). Later read accesses read the actual level at
port 4. If bit 3 in the control word is active, P4 is used as
an R/W-line. If the internal CPU is active, R/W is an output
line, otherwise it is an input. But P4 has another, very
important function during RESET. The level at P4 during
RESET decides whether the control word is read from
the internal ROM (FFF9H) or from the external memory.
It is therefore important that the desired level during RESET
is set at P4. An internal pull-down resistor of approx.
100 kW is integrated in the CCU 3001, which ensures
that the control word is read by the internal ROM. The
external control word access is obtained via an external
pull-up resistor of approx. 5 kW. The CCU 3000 has an
internal pull-up resistor at P4 (external ROM access).
The further mode of operation of the CCU 3000, CCU
3001 depends only on the control word though.
Please note that this mode is always necessary for
the CCU 3000 since this device does not have internal
ROM!
2.7. I/O-Lines P50 to P55
The 6 additional I/O-lines have a two-fold function:
– input or output line (open drain output) or
– fully decoded I/O-select lines (push-pull outputs)
As a rule these lines can be used as input or output lines.
As soon as ports 1 to 4 are used as system bus, they are
lost as I/O-channels. However, a total of 48 port lines (24
inputs and outputs each) can be reconstructed without
difficulties (1 housing for 8 lines), if the additional 6 I/Olines
of the CCU 3000, CCU 3001 are switched into the
port select mode. They then represent the select lines of
the original ports 1 to 3. Each line can be defined as I/O
or port select line separately. In the I/O-page three bytes
are needed.



SMPS POWER Supply is based on TDA4600 (SIEMENS).LOEWE CALIDA 72  Super Flatline Art. Nr. 52460 L17   CHASSIS 110C93 (C9003)
 Power supply Description based on TDA4601d (SIEMENS)

 

TDA4601 Operation. * The TDA4601 device is a single in line, 9 pin chip. Its predecessor was the TDA4600 device, the TDA4601 however has improved switching, better protection and cooler running. The (SIEMENS) TDA4601 power supply is a fairly standard parallel chopper switch mode type, which operates on the same basic principle as a line output stage. It is turned on and off by a square wave drive pulse, when switched on energy is stored in the chopper transformer primary winding in the form of a magnetic flux; when the chopper is turned off the magnetic flux collapses, causing a large back emf to be produced. At the secondary side of the chopper transformer this is rectified and smoothed for H.T. supply purposes. The advantage of this type of supply is that the high chopping frequency (20 to 70 KHz according to load) allows the use of relatively small H.T. smoothing capacitors making smoothing easier. Also should the chopper device go short circuit there is no H.T. output. In order to start up the TDA4601 I.C. an initial supply of 9v is required at pin 9, this voltage is sourced via R818 and D805 from the AC side of the bridge rectifier D801, also pin 5 requires a +Ve bias for the internal logic block. (On some sets pin 5 is used for standby switching). Once the power supply is up and running, the voltage on pin 9 is increased to 16v and maintained at this level by D807 and C820 acting as a half wave rectifier and smoothing circuit. PIN DESCRIPTIONS Pin 1 This is a 4v reference produced within the I.C. Pin 2 This pin detects the exact point at which energy stored in the chopper transformer collapses to zero via R824 and R825, and allows Q1 to deliver drive volts to the chopper transistor. It also opens the switch at pin 4 allowing the external capacitor C813 to charge from its external feed resistor R810. Pin 3 H.T. control/feedback via photo coupler D830. The voltage at this pin controls the on time of the chopper transistor and hence the output voltage. Normally it runs at Approximately 2v and regulates H.T. by sensing a proportion of the +4v reference at pin 1, offset by conduction of the photo coupler D830 which acts like a variable resistor. An increase in the conduction of transistor D830 and therefor a reduction of its resistance will cause a corresponding reduction of the positive voltage at Pin 3. A decrease in this voltage will result in a shorter on time for the chopper transistor and therefor a lowering of the output voltage and vice versa, oscillation frequency also varies according to load, the higher the load the lower the frequency etc. should the voltage at pin 3 exceed 2.3v an internal flip flop is triggered causing the chopper drive mark space ratio to extend to 244 (off time) to 1 (on time), the chip is now in over volts trip condition. Pin 4 At this pin a sawtooth waveform is generated which simulates chopper current, it is produced by a time constant network R810 and C813. C813 charges when the chopper is on and is discharged when the chopper is off, by an internal switch strapping pin 4 to the internal +2v reference, see Fig 2. The amplitude of the ramp is proportional to chopper drive. In an overload condition it reaches 4v amplitude at which point chopper drive is reduced to a mark-space ratio of 13 to 1, the chip is then in over current trip. The I.C. can easily withstand a short circuit on the H.T. rail and in such a case the power supply simply squegs quietly. Pin 4 is protected by internal protection components which limit the maximum voltage at this pin to 6.5v. Should a fault occur in either of the time constant components, then the chopper transistor will probably be destroyed. Pin 5 This pin can be used for remote control on/off switching of the power supply, it is normally held at about +7v and will cause the chip to enter standby mode if it falls below 2v. Pin 6 Ground. Pin 7 Chopper switch off pin. This pin clamps the chopper drive voltage to 1.6v in order to switch off the chopper. Pin 8 Chopper base current output drive pin. Pin 9 L.T. pin, approximately 9v under start-up conditions and 16v during normal running, Current consumption of the I.C. is typically 135mA. The voltage at this pin must reach 6.7v in order for the chip to start-up.

Semiconductor circuit for supplying power to electrical equipment, comprising a transformer having a primary winding connected, via a parallel connection of a collector-emitter path of a transistor with a first capacitor, to both outputs of a rectifier circuit supplied, in turn, by a line a-c voltage; said transistor having a base controlled via a second capacitor by an output of a control circuit acted upon, in turn by the rectified a-c line voltage as actual value and by a reference voltage; said transformer having a first secondary winding to which the electrical equipment to be supplied is connected; said transformer having a second secondary winding with one terminal thereof connected to the emitter of said transistor and the other terminal thereof connected to an anode of a first diode leading to said control circuit; said transformer having a third secondary winding with one terminal thereof connected, on the one hand, via a series connection of a third capacitor with a first resistance, to the other terminal of said third secondary winding and connected, on the other hand, to the emitter of said transistor, the collector of which is connected to said primary winding; a point between said third capacitor and said first resistance being connected to the cathode of a second diode; said control circuit having nine terminals including a first terminal delivering a reference voltage and connected, via a voltage divider formed of a third and fourth series-connected resistances, to the anode of said second diode; a second terminal of said control circuit serving for zero-crossing identification being connected via a fifth resistance to said cathode of said second diode; a third terminal of said control-circuit serving as actual value input being directly connected to a divider point of said voltage divider forming said connection of said first terminal of said control circuit to said anode of said second diode; a fourth terminal of said control circuit delivering a sawtooth voltage being connected via a sixth resistance to a terminal of said primary winding of said transformer facing away from said transistor; a fifth terminal of said control circuit serving as a protective input being connected, via a seventh resistance to the cathode of said first diode and, through the intermediary of said seventh resistance and an eighth resistance, to the cathode of a third diode having an anode connected to an input of said rectifier circuit; a sixth terminal of said control circuit carrying said reference potential and being connected via a fourth capacitor to said fourth terminal of said control circuit and via a fifth capacitor to the anode of said second diode; a seventh terminal of said control circuit establishing a potential for pulses controlling said transistor being connected directly and an eighth terminal of said control circuit effecting pulse control of the base of said transistor being connected through the intermediary of a ninth resistance to said first capacitor leading to the base of said transistor; and a ninth terminal of said control circuit serving as a power supply input of said control circuit being connected both to the cathode of said first diode as well as via the intermediary of a sixth capacitor to a terminal of said second secondary winding as well as to a terminal of said third secondary winding.

Description:

The invention relates to a blocking oscillator type switching power supply for supplying power to electrical equipment, wherein the primary winding of a transformer, in series with the emitter-collector path of a first bipolar transistor, is connected to a d-c voltage obtained by rectification of a line a-c voltage fed-in via two external supply terminals, and a secondary winding of the transformer is provided for supplying power to the electrical equipment, wherein, furthermore, the first bipolar transistor has a base controlled by the output of a control circuit which is acted upon in turn by the rectified a-c line voltage as actual value and by a set-point transmitter, and wherein a starting circuit for further control of the base of the first bipolar transistor is provided.
Such a blocking oscillator switching power supply is described in the German periodical, "Funkschau" (1975) No. 5, pages 40 to 44. It is well known that the purpose of such a circuit is to supply electronic equipment, for example, a television set, with stabilized and controlled supply voltages. Essential for such switching power supply is a power switching transistor i.e. a bipolar transistor with high switching speed and high reverse voltage. This transistor therefore constitutes an important component of the control element of the control circuit. Furthermore, a high operating frequency and a transformer intended for a high operating frequency are provided, because generally, a thorough separation of the equipment to be supplied from the supply naturally is desired. Such switching power supplies may be constructed either for synchronized or externally controlled operation or for non-synchronized or free-running operation. A blocking converter is understood to be a switching power supply in which power is delivered to the equipment to be supplied only if the switching transistor establishing the connection between the primary coil of the transformer and the rectified a-c voltage is cut off. The power delivered by the line rectifier to the primary coil of the transformer while the switching transistor is open, is interim-stored in the transformer and then delivered to the consumer on the secondary side of the transformer with the switching transistor cut off.
In the blocking converter described in the aforementioned reference in the literature, "Funkschau" (1975), No. 5, Pages 40 to 44, the power switching transistor is connected in the manner defined in the introduction to this application. In addition, a so-called starting circuit is provided. Because several diodes are generally provided in the overall circuit of a blocking oscillator according to the definition provided in the introduction hereto, it is necessary, in order not to damage these diodes, that due to the collector peak current in the case of a short circuit, no excessive stress of these diodes and possibly existing further sensitive circuit parts can occur.
Considering the operation of a blocking oscillator, this means that, in the event of a short circuit, the number of collector current pulses per unit time must be reduced. For this purpose, a control and regulating circuit is provided. Simultaneously, a starting circuit must bring the blocking converter back to normal operation when the equipment is switched on, and after disturbances, for example, in the event of a short circuit. The starting circuit shown in the literature reference "Funkschau" on Page 42 thereof, differs to some extent already from the conventional d-c starting circuits. It is commonly known for all heretofore known blocking oscillator circuits, however, that a thyristor or an equivalent circuit replacing the thyristor is essential for the operation of the control circuit.
It is accordingly an object of the invention to provide another starting circuit. It is a further object of the invention to provide a possible circuit for the control circuit which is particularly well suited for this purpose. It is yet another object of the invention to provide such a power supply which is assured of operation over the entire range of line voltages from 90 to 270 V a-c, while the secondary voltages and secondary load variations between no-load and short circuit are largely constant.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a blocking oscillator-type switching power supply for supplying power to electrical equipment wherein a primary winding of a transformer, in series with an emitter-collector path of a first bipolar transistor, is connected to a d-c voltage obtained by rectification of a line a-c voltage fed-in via two external supply terminals, a secondary winding of the transformer being connectible to the electrical equipment for supplying power thereto, the first bipolar transistor having a base controlled by the output of a control circuit acted upon, in turn, by the rectified a-c line voltage as actual value and by a set-point transmitter, and including a starting circuit for further control of the base of the first bipolar transistor, including a first diode in the starting circuit having an anode directly connected to one of the supply terminals supplied by the a-c line voltage and a cathode connected via a resistor to an input serving to supply power to the control circuit, the input being directly connected to a cathode of a second diode, the second diode having an anode connected to one terminal of another secondary winding of the transformer, the other secondary winding having another terminal connected to the emitter of the first bipolar transmitter.
In accordance with another feature of the invention, there is provided a second bipolar transistor having the same conduction type as that of the first bipolar transistor and connected in the starting circuit with the base thereof connected to a cathode of a semiconductor diode, the semiconductor diode having an anode connected to the emitter of the first bipolar transistor, the second bipolar transistor having a collector connected via a resistor to a cathode of the first diode in the starting circuit, and having an emitter connected to the input serving to supply power to the control circuit and also connected to the cathode of the second diode which is connected to the other secondary winding of the transformer.
In accordance with a further feature of the invention, the base of the second bipolar transistor is connected to a resistor and via the latter to one pole of a first capacitor, the anode of the first diode being connected to the other pole of the first capacitor.

In accordance with an added feature of the invention, the input serving to supply power to the control circuit is connected via a second capacitor to an output of a line rectifier, the output of the line rectifier being directly connected to the emitter of the first bipolar transistor.
In accordance with an additional feature of the invention, the other secondary winding is connected at one end to the emitter of the first bipolar transistor and to a pole of a third capacitor, the third capacitor having another pole connected, on the one hand, via a resistor, to the other end of the other secondary winding and, on the other hand, to a cathode of a third diode, the third diode having an anode connected via a potentiometer to an actual value input of the control circuit and, via a fourth capacitor, to the emitter of the first bipolar transistor.
In accordance with yet another feature of the invention, the control circuit has a control output connected via a fifth capacitor to the base of the first bipolar transistor for conducting to the latter control pulses generated in the control circuit.
In accordance with a concomitant feature of the invention, there is provided a sixth capacitor shunting the emitter-collector path of the first transistor.
Other features which are considered as characteristic for the invention are set forth in the appended claim.
Although the invention is illustrated and described herein as embodied in a blocking oscillator type switching power supply, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.