Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and information about some of the electronic, electrical and electrotechnical technology relics that the Frank Sharp Private museum has accumulated over the years .

Premise: There are lots of vintage electrical and electronic items that have not survived well or even completely disappeared and forgotten.

Or are not being collected nowadays in proportion to their significance or prevalence in their heyday, this is bad and the main part of the death land. The heavy, ugly sarcophagus; models with few endearing qualities, devices that have some over-riding disadvantage to ownership such as heavy weight,toxicity or inflated value when dismantled, tend to be under-represented by all but the most comprehensive collections and museums. They get relegated to the bottom of the wants list, derided as 'more trouble than they are worth', or just forgotten entirely. As a result, I started to notice gaps in the current representation of the history of electronic and electrical technology to the interested member of the public.


Following this idea around a bit, convinced me that a collection of the peculiar alone could not hope to survive on its own merits, but a museum that gave equal display space to the popular and the unpopular, would bring things to the attention of the average person that he has previously passed by or been shielded from. It's a matter of culture. From this, the Obsolete Technology Tellye Web Museum concept developed and all my other things too. It's an open platform for all electrical Electronic TV technology to have its few, but NOT last, moments of fame in a working, hand-on environment. We'll never own Colossus or Faraday's first transformer, but I can show things that you can't see at the Science Museum, and let you play with things that the Smithsonian can't allow people to touch, because my remit is different.

There was a society once that was the polar opposite of our disposable, junk society. A whole nation was built on the idea of placing quality before quantity in all things. The goal was not “more and newer,” but “better and higher" .This attitude was reflected not only in the manufacturing of material goods, but also in the realms of art and architecture, as well as in the social fabric of everyday life. The goal was for each new cohort of children to stand on a higher level than the preceding cohort: they were to be healthier, stronger, more intelligent, and more vibrant in every way.

The society that prioritized human, social and material quality is a Winner. Truly, it is the high point of all Western civilization. Consequently, its defeat meant the defeat of civilization itself.

Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

OLD, but ORIGINAL, Well made, Funny, Not remotely controlled............. and not Made in CHINA.

How to use the site:

- If you landed here via any Search Engine, you will get what you searched for and you can search more using the search this blog feature provided by Google. You can visit more posts scrolling the left blog archive of all posts of the month/year,
or you can click on the main photo-page to start from the main page. Doing so it starts from the most recent post to the older post simple clicking on the Older Post button on the bottom of each page after reading , post after post.

You can even visit all posts, time to time, when reaching the bottom end of each page and click on the Older Post button.

- If you arrived here at the main page via bookmark you can visit all the site scrolling the left blog archive of all posts of the month/year pointing were you want , or more simple You can even visit all blog posts, from newer to older, clicking at the end of each bottom page on the Older Post button.
So you can see all the blog/site content surfing all pages in it.

- The search this blog feature provided by Google is a real search engine. If you're pointing particular things it will search IT for you; or you can place a brand name in the search query at your choice and visit all results page by page. It's useful since the content of the site is very large.

Note that if you don't find what you searched for, try it after a period of time; the site is a never ending job !

Every CRT Television saved let revive knowledge, thoughts, moments of the past life which will never return again.........

Many contemporary "televisions" (more correctly named as displays) would not have this level of staying power, many would ware out or require major services within just five years or less and of course, there is that perennial bug bear of planned obsolescence where components are deliberately designed to fail and, or manufactured with limited edition specificities..... and without considering........picture......sound........quality........

..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

Have big FUN ! !
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©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All sets and apparates appearing here are property of
Engineer Frank Sharp. NOTHING HERE IS FOR SALE !

Monday, March 28, 2011

PANASONIC TX-25A3C YEAR 1994.











The PANASONIC  TX-25A3C  is the first DIGITAL TELEVISION set From Panasonic TV models.

Until the coming of this model Panasonic was producing excellent analog technology tellyes.

With this model, Panasonic, is , like other high class fabricants, adopting the DIGIVISION ITT Digital Signal Processing Technology, using the ITT DIGIVISION DIGIT2000 Fast chipset improving furthermore picture quality and sound.
The television receiver has an alphanumeric display  which appears on the picture tube screen, to give the user data on the tuned channel number, colour settings and other operating data. The digital processor which generates the characters for display also controls the channel setting, etc., under the control of a digital remote control unit . The processor  has an associated memory circuit  for permanent tuning back up. The control of the capacitance diode tuner  is achieved by the processor  altering the dividing factor of a feedback loop to a phase/frequency comparator . The other input to the comparator is a divided frequency from a quartz oscillator.


The PANASONIC  TX-25A3C  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 PANASONIC TX-25A3C   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 PANASONIC  TX-25A3C    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.

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).



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

The PANASONIC  TX-25A3C was featuring in this model for sirst time  an Adaptive Combifilter Video Processing:
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.


All PANASONIC BIG sets from this to a time line of 10 12 Years are digital or even 100HZ Scan rate technology.

This set was quickly replaced with models fitting the new CHASSIS EURO-2 using the ITT DIGIT3000 chipset which you already seen here at Obsolete Tecnology Tellye Museum !

These were widely used by Panasonic until they decided in a brief time to drop all digital technology and return to analog CRT TUBE set employing the UOC 1 and the UOC 3 PHILIPS technology and then completely switch off to Flat Panels and Plasma sets.

The PANASONIC  TX-25A3C set here shown has 25 Inches FSQ screen with black matrix and 100 Programs, Teletext, HIFI Stereo sound, Many connectivity sockets, Advanced OSD and many others features.

Needless to say: Picture is superb thanks even to a selected PHILIPS 45AX IMPROVED CRT TUBE, together with sound.

(Heavy set anyway).


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An Increasingly Versatile Device The domestic television set used to be simply the thing that reproduced the programmes transmitted by one or other of the three programme networks  unless you happened to be connected to one of the wire systems that have experimented with local TV and pay TV at various times. But have you noticed what an increasingly versatile thing the TV set is becoming?
- The first major extension to the domestic TV set's possibilities came with the VCR, enabling you to record off air or replay prerecorded tapes. Domestic VTR systems have at a price  been with us for roughly a decade now, but till the advent of the easy to handle VCR most low-cost VTR systems were intended for use with monitors, with the signal interconnections at video and audio frequencies.
- Then came TV games, first found in the pubs and amusement arcades, later appearing in compact, relatively inexpensive packages for home use. The significant point here was the entry of digital techniques on the domestic TV scene. On the broadcast side, digital techniques had been making a substantial contribution to operations for some years, starting with the BBC's sound-in-syncs system (1969) in which the TV sound signal is compressed, converted to digital form and inserted in the line sync pulse period, and culminating with the IBA's famed DICE, which provides electronic standards (lines, fields, colour) conversion by converting the signals to digital form, processing them, then converting them back into analogue form.
Rather far from TV games you might think, but it's all part of the same process - the increasing impact of digital techniques on the world of television. In fact the technology of TV games has evolved considerably since their first appearance.
The approach then was to employ a fair number of standard digital i.c.s to build up the circuitry required. But why not go about it in the same way as the calculator manufacturers?
It didn't take long for the semiconductor people to see this new possibility for using their l.s.i. technology. This made it a relatively simple matter to provide a range of games with just a single i.c.  the basis of the present generation of TV games.
Add a second i.c. and the whole thing comes up in glorious colour. But it doesn't end there. The talk was now is of adopting microprocessor technology and making the system programmable, so that an almost unlimited range of games of varying degrees of complexity can be played. The favoured system seems to been to use prerecorded cassettes to provide the various programmes. And once you do that, you can extend the system to all sorts of other uses - teaching systems and so on. In fact you've made the TV set into part of a home computer installation - as we outlined in Teletopics last month. It's not impossible then to imagine some "viewers" using their TV sets for games, instruction and VCR use, while keeping up to date with teletext news and getting extra information via the PO's Viewdata system - and never watching a transmitted programme at all! We've come a long way then from the days of the TV set as a goggle
(goggle ????? or gooooooooooogle).................. box.
Teletext decoders and TV games were already being built into a few sets. What other digital innovations can we expect in TV sets? (may be DVB)
One now well established use of digital techniques is to provide all electronic channel selection.
The varicap tuner simply asks to be controlled in this way, and the system lends itself readily to remote control operation. Once you're controlling the tuner and generating various signals digitally there are other things you might as well do. Like flashing the selected channel number on the screen, or the time (coming shortly in Television!). Sets which do this sort of thing have been available on the Continent for some while now.
- The latest development along these lines is the picture within a picture a reduced size picture from another channel being inserted in the corner of the main display (PIP), so that you can watch two progrpnmes at once or see when to change over to a programme due to start on another channel. This involves some interesting digital processes - you've got to lose lines, and compact the video information by reading it into a memory at one speed and reading it out at another, in effect operating at two standards simultaneously while keeping both in sync (remember how difficult it has sometimes been to keep a set in sync on one standard!).
- There's only one thing that prevents a space-age TV installation in every home: cost.
But the cost of electronic hardware has a habit of falling dramatically once production has achieved a certain level. TV games are already commonplace, and teletext decoders have  become a lot cheaper once specialised i.c. modules for the purpose go into large scale production. From this point in time, it already seems that one can regard the days when the TV set simply displayed one of the programmes available as the age of stream TV.

....................................But we all know how it ended !


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...............................


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Panasonic Corporation ( Panasonikku Kabushiki-gaisha) (TYO: 6752, NYSE: PC), formerly known as Matsushita Electric Industrial Co., Ltd. ( Matsushita Denki Sangyō Kabushiki-gaisha), is a Japanese multinational consumer electronics corporation headquartered in Kadoma, Osaka, Japan. Its main business is in electronics manufacturing and it produces products under a variety of names including Panasonic and Technics. Since its founding in 1918, it has grown to become the largest Japanese electronics producer. In addition to electronics, Panasonic offers non-electronic products and services such as home renovation services. Panasonic was ranked the 89th-largest company in the world in 2009 by the Forbes Global 2000 and is among the Worldwide Top 20 Semiconductor Sales Leaders !

History

Panasonic was founded in 1918 by Konosuke Matsushita first selling duplex lamp sockets. In 1927, it produced a bicycle lamp, the first product it marketed under the brand name National. It operated factories in Japan and other parts of Asia through the end of World War II, producing electrical components and appliances such as light fixtures, motors, and electric irons.
After World War II, Panasonic regrouped and began to supply the post war boom in Japan with radios and appliances, as well as bicycles. Matsushita's brother-in-law, Toshio Iue founded Sanyo as a subcontractor for components after WWII. Sanyo grew to become a competitor to Panasonic.

Name

For 90 years since establishment, the name of the company was always topped with ("Matsushita"). The company's name before 1 October 2008 had been "Matsushita Electric Industrial Co., Ltd.", used since 1935.
In 1927, the company founder adopted a brand name "National" ( National) for a new lamp product, knowing "national" meant "of or relating to a people, a nation."[5] In 1955, the company labeled its export audio speakers and lamps "PanaSonic", which was the first time it used its "Panasonic" brand name.
The company began to use a brand name "Technics" in 1965.[6] The use of multiple brands lasted for some decades.[6]
In May 2003, the company put "Panasonic" as its global brand, and set its global brand slogan, "Panasonic ideas for life."[7] The company began to unify its brands to "Panasonic" and, by March 2004 replaced "National" for products and outdoor signboards, except for those in Japan[7].
On January 10, 2008, the company announced that it would change its name to "Panasonic Corporation" (effective on October 1, 2008) and phase out the brand "National" in Japan, replacing it with the global brand "Panasonic" (by March 2010). The name change was approved at a shareholders' meeting on June 26, 2008 after consultation with the Matsushita family. Panasonic owns RCTI, Global TV and MNC TV.

Electronics

In 1961, Konosuke Matsushita traveled to the United States and met with American dealers. Panasonic began producing television sets for the U.S. market under the Panasonic brand name, and expanded the use of the brand to Europe in 1979.
The company used the National trademark outside of North America during the 1950s through the 1970s. (The trademark could not be used probably due to discriminatory application of trademark laws where brands like General Motors were registrable.) It sold televisions, hi-fidelity stereo receivers, multi-band shortwave radios, and marine radio direction finders, often exported to North America under various U.S. brand names. The company also developed a line of home appliances such as rice cookers for the Japanese and Asian markets. Rapid growth resulted in the company opening manufacturing plants around the world. National/Panasonic quickly developed a reputation for well-made, reliable products.
The company debuted a hi-fidelity audio speaker in Japan in 1965 with the brand Technics. This line of high quality stereo components became worldwide favorites. The most famous product still made today is the SL-1200 record player, known for its high performance, precision, and durability. Throughout the 1970s and early 1980s, Panasonic continued to produce high-quality specialized electronics for niche markets such as shortwave radios, as well as developing a successful line of stereo receivers, CD players, and other components.
Since 2004, Toyota has used Panasonic batteries for its Toyota Prius, an environmentally friendly car made in Japan.

On January 19, 2006 Panasonic announced that, starting in February, it will stop producing analog televisions (then 30% of its total TV business) to concentrate on digital TVs.
On November 3, 2008 Panasonic and Sanyo were in talks, resulting in the eventual acquisition of Sanyo. The merger was completed in December 2009, and resulted in a mega-corporation with revenues over ¥11.2 trillion (around $110 billion). As part of what will be Japan's biggest electronics company, the Sanyo brand and most of the employees will be retained as a subsidiary.
In November 1999, the Japan Times reported that Panasonic planned to develop a "next generation first aid kit" called the Electronic Health Checker. At the time, the target market was said to be elderly people, especially those living in rural areas where medical help might not be immediately available, so it was planned that the kit would include support for telemedicine. The kits were then in the testing stage, with plans for eventual overseas distribution, to include the United States.
In recent years the company has been involved with the development of high-density optical disc standards intended to eventually replace the DVD and the SD memory card.
On July 29, 2010 Panasonic reached an agreement to acquire the remaining shares of Panasonic Electric Works and Sanyo shares for $9.4 billion.

Panasonic and Universal

Panasonic used to own Universal Studios, then known as the Music Corporation of America, since acquiring the company in 1990 but sold it to Seagram in 1995. Universal Studios is now a unit of NBC Universal.



JAPAN IS STRANGE
Strange how situations change. It seems not so long ago that Japan and its industries, particularly electronics, could do no wrong. They taught us how to make cars and TV sets properly. They invested heavily and came up with a seem- ingly endless stream of desirable, innova- tive products. Both outsiders and insiders could see no end to this success story. We were told, by more than one leading Japanese electronics industrialist, that the 21st century would be the Japanese one, when Japan became predominant industri- ally and culturally. For the last couple of years the situation has been somewhat different. Japan is still the world's second largest economy, but the previous confidence has gone. The econo- my has stalled, and doesn't look like getting going again for some time. Profitability has become appalling, and the talk now is all of restructuring and job losses. Sony has announced that some 17,000 jobs will be lost worldwide, ten per cent of its workforce, while fifteen of its seventy factories are to be closed. Mighty Hitachi, whose activities span a much wider field and whose turnover is equivalent to over two per cent of Japan's gross domestic product, has launched a detailed review of its businesses. 6,500 of its 66,000 parent company employees are to be made redun- dant by March next year. On a consolidat- ed basis Hitachi is Japan's largest employ- er, with 330,000 staff. Businesses are to be dropped or reorganised. The story from Mitsubishi Electric is similar: there is to be a "sweeping restructuring of its portfolio of businesses". In the UK, the latest manifes- tation of this is the closure of Mitsubishi's VCR plant at Livingston. 14,500 jobs will go (8,400 in Japan) at Mitsubishi Electric, nearly ten per cent of the workforce. Other manufacturers who have announced poor results and restructuring recently include NEC, Matsushita, Sharp and Toshiba. It's all a long way since the time when, it seemed, all the Japanese had to do was to get the product right and produce more and more of it. Some of this was foreseeable. Markets reach saturation point; new products are not always a runaway success; if investment in new plant is excessive you end up with too much capacity; and so on. Then there is the fact that Japan is not isolated from econom- ic problems elsewhere: no economy that is heavily dependent on exports can be. But there are also more specific Japanese prob- lems. The banking system is beset by non- performing loans that Japanese bankers are reluctant to write off. The bubble economy of a few years ago, when asset values rose to unrealistic levels, collapsed. This is part of the cause of the banking system difficul- ties. Then there is the practice of cross - ownership, with firms owning substantial stakes in each other. This can work nicely when everything is doing well: when reces- sion looms, it aggravates the problems. Japan's unemployment rate hit a new high of 4.8 per cent (3.39m) in March, part- ly because of the corporate sector restructur- ing. Japanese industrialists hope to improve their profitability in the second half of the year, and will be helped by improved condi- tions in SE Asia. But it will be hard going, particularly to improve domestic market conditions. The Japanese have always had a high propensity to save. This increases when the economic climate is poor, with unemployment a threat. Right now Japanese consumers are saving rather than buying. No one seems to know how to alter their behaviour. There is also a demographic problem: the Japanese population is ageing. Japanese interest rates are negligible. So borrowing is not a problem. But conversely all those savings are bringing in little income. In the Western world interest rate changes often have a considerable impact on the economy. This economic tool is not available when interest rates are negligible. The Japanese have been advised to get their banking system sorted out, but that's not the sort of thing that can be done overnight. Right now the best opportunity for Japan seems to be to export its way out of its dif- ficulties, something that shouldn't be too difficult once worldwide expansion has resumed. But the high value of the yen is a drawback. From the economic viewpoint it's an extremely interesting situation, one in which the laws of economics have little to offer. This could be because such laws are, basically, descriptive rather than prescrip- tive. In the real world you can't always ini- tiate economic activity through monetary or fiscal means. Some commentators have gone so far as to suggest that the Japanese government should spend, spend, spend and print money to kick-start the economy. This is a dangerous course that can go badly wrong. It has already been tried by the Japanese government to a limited extent, with similarly limited success. The one thing that we do know is that economies are not stable. Change is ever present in one form or another. The prob- lem lies in trying to control it. This is all rather humbling, and certainly something of a comeuppance for the rather arrogant Japanese industrialists who had talked about the century of Japanese economic hegemony.




PANASONIC TX-25A3C CHASSIS EURO-1 INTERNAL VIEW.























































































The Panasonic EURO-1 Is the first PANASONIC TV CHASSIS entirely Digital Technology.

IT Is completely based on the ITT DIGIVISION DIGIT2000 Chipset technology but furtherer improved by ITT adding more improvement functions in the original DIGIT2000.


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

Indeed there are newly named IC's such as:

- VDU2146 Video Display Unit.

- DTI2223 Digital Transient Improvement

- ACVP2205 Adaptive Combifilter Video Processing

- MCU2600 Main Clock Unit

- SPU2243 Secam Processing Unit

- DPU2553 Deflection Processor Unit

- SAD2140 Signal Analog to Digital Conversion

- TPU2735 Teletext Processor Unit

- CCU3000 Computer control Unit

- MN8333 Digital feature Unit (Panasonic)

- ACP2371 Audio Control Processing




Technology overview:ACVP2205 (Adaptive Combifilter Video Processing)
In 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.The ACVP 2205 is a digital real–time signal processor for multistandard color TV sets based on the DIGIT2000
system. It handles composite video signals as well as
S–VHS signals. For PAL and NTSC a 2H adaptive
combfilter is implemented. It considerably improves the
picture quality by a sophisticated luminance and chrominance
separation. A single silicon chip contains the following
functions:
– selectable 7 or 8 bit video input
– code converter and a data demultiplexer for composite
and S–VHS input signals
– 2H adaptive combfilter for PAL and NTSC composite
video signals
– adjustable horizontal and vertical peaking filter for luminance
– selectable luminance filter for enhanced frequency response
– black–level–expander for improving the picture contrast
and the gamma correction
– contrast multiplier with limiter for the luminance signal
– adjustable chrominance filter
– all color signal processing circuits such as automatic
color control (ACC), color killer, PAL identification, decoder
with PAL compensation, hue correction
– color saturation multiplier with multiplexer for the color
difference signals
– IM bus interface for communication with the CCU 2070
or CCU 3000 Central Control Unit
– circuitry for measuring dark current (CRT spot–cutoff),
white level and photo current, and for transferring this
data to the CCU.
The ACVP 2205 is pin compatible to the PVPU 2204 . It
is designed in N–MOS technology and is available in a
40 pin Dil plastic package.
2. Functional Description
Supplied by one of the DIGIT2000 A/D converters (VCU
2136 or SAD 2140), the ACVP 2205 separates the video
signal into luminance and chrominance. These two signals
are processed in different circuits, which will be described
in the following. The output signals are reconverted
to analog signals in the VCU 2136 or VDU 2146.
Their RGB output amplifiers are used to drive the cathodes
of the CRT (see Fig. 2–4). Additionally, the ACVP
2205 performs a number of measurements and control
operations (in conjunction with the VCU 2136 or VDU
2146)relating to picture tube alignment such as spot–
cutoff current adjustment, white level control, beam current
limiting, etc.
For a multistandard application including SECAM, the
SPU 2243 SECAM Chroma Processor must be connected
in parallel to the ACVP 2205 for chroma processing.
The different processing delays Dt can be equalized
in the DTI 2223.

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.




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.


TEA6415C Bus-Controlled Video Matrix Switch
Main Features
20 MHz Bandwidth
Cascadable with another TEA6415C (Internal
Address can
be changed by Pin 7 Voltage)
8 Inputs (CVBS, RGB, Chroma, ...)
6 Outputs
Possibility of Chroma Signal for each Input
by switching off the Clamp with an external
Resistor Bridge
Bus Controlled
6.5 dB Gain between any Input and Output
-55 dB Crosstalk at 5 MHz
Full ESD Protection

Description
The main function of the TEA6415C is to switch 8
video input sources on the 6 outputs.
Each output can be switched to only one of the
inputs, whereas any single input may be connected
to several outputs.
All switching possibilities are controlled through the
I2C bus.

Driving a 75 W load requires an external transistor.
The switches configuration is defined by words of 16 bits: one word of 16 bits for each output
channel.
So, 6 words of 16 bits are necessary to determine the starting configuration upon power-on (power supply: 0 to 10V). But a new configuration needs only the words of the changed output channels.

Using a Second TEA6415C
The programming input pin (PROG) allows two TEA6415C circuits to operate in parallel and to select them independently through the I²C bus by modifying the address byte. Consequently, the switching capabilities are doubled, or IC1 and IC2 can be cascaded.





TEA6420 BUS-CONTROLLED AUDIO MATRIX SWITCH


5 Stereo Inputs
4 Stereo Ouputs

Gain Control 0/2/4/6dB/Mute for each Output
cascadable (2 different addresses) Serial Bus Controlled Very low Noise
Very low Distorsion
DESCRIPTION The TEA6420 switches 5 stereo audio inputs on 4stereo outputs. All the switching possibilities are changed through the I2C bus.



The power Supply is based on TDA4601 (SIEMENS)





Power supply is 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.
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.

TDA8175 TV VERTICAL DEFLECTION OUTPUT CIRCUIT:

 DESCRIPTION
The TDA8175 is a monolithic integrated circuit in
HEPTAWATT package. It is a high efficiency power
booster for direct driving of vertical windings of TV
yokes. It is intended for use in Color and B & W
television sets as well as in monitors and displays.

 .POWER AMPLIFIER
 .FLYBACK GENERATOR 
.AUTOMATIC PUMPING COMPENSATION 
.THERMAL PROTECTION .
.REFERENCE VOLTAGE

ABSOLUTE MAXIMUMRATINGS
Symbol Parameter Value Unit
VS Supply Voltage (PIn 2) 35 V
V5, V6 Flyback Peak Voltage 60 V
V3 Voltage at PIn 3 +VS
V1, V7 Amplifier Input Voltage +VS
IO Output Peak Current (non-repetitive, t = 2ms) 2.5 A
IO Output Peak Current at :
f = 50 or 60Hz, t 3 10ms
f = 50 or 60Hz, t > 10ms
32
AA
I3 Pin 3 DC Current at V5 < V2 100 mA
I3 Pin 3 Peak-to-peak Flyback Current at f = 50 or 60Hz, tfly 3 1.5ms 3 A
Ptot Total Power Dissipation at Tcase = 70oC 20 W
Tj, Tstg Storage and Junction Temperature -40, +150 oC