Відео

I worked as a TV engineer for 19 years. I know all the disadvantages and artifacts of SECAM very well. Some authors during the USSR claimed that the USSR adopted SECAM "for political reasons" (friendship with France). And they called SECAM "a joint Soviet-French system" I can tell about the real reasons for adopting SECAM and some other interesting facts. 1 - the USSR long-distance microwave lines, due to their low quality, could not transmit an NTSC signal and had limitations for transmitting PAL 2 - PAL system equipment requires a high production culture and precision tolerances for each element, so the USSR industry was not ready even for the mass production of quartz crystals and delay lines. 3 - Thomson CSF, in addition to TV equipment, was a European leader in the production of electronic equipment for the armies of NATO countries. Soviet intelligence wanted to introduce its agents into this company and recruit French specialists. That is why the USSR began to cooperate with Thomson CSF. 4. The USSR agreed with Thomson CSF on the absence of license fees only for equipment for TV studios. However, the USSR did not pay France license fees for each color TV sold. In the mid-1980s, there was a demand for PAL decoders for owners of video recorders. Many engineers, technicians, and radio amateurs began to private manufacture PAL decoders and earned decent money. French intelligence recruited Soviet intelligence officer Vladimir Vetrov (agent Farewell), who was interested in Thomson CSF developments. After this, the CIA and its French colleagues passed to USSR through Vetrov fake documentation on missile defense systems, including the Shuttle. And this finally brought down the Soviet economy, which was focused on arms production.

this is one of the coolest things i have seen in my entire life and it saddens me greatly that i will probably never be this kind of person

The French system was much better than PAL and NTSC.

where can i find a device that allows me to plug a composite device into an s-vid port? i have a tv that disables composite any time s-vid devices are plugged in. to use composite, i have to physically remove the s-vid cable from the back of the TV, a burden. after such a conversion is applied, i'd just use a multi device selector so all my s-vids can comfortably use the 1 port on the back of the TV.

Finally got one running but no NICAM on my Arcam decoder? Anybody else had issues with NICAM video is great and it’s not dropping any frames.

Used one of these with accompanying waveform monitor for many years. Very reliable.

Great tests. Well composite video doesn’t look that bad as i was expecting. Some of my old game consoles do have worse composite out with lots of fuzzy artifacts in them like on the nes wich can be very annoying, especially if there are lots of details on screen.

Fascinated by this (and I have a DMAC box to make a video about) but initially I only have a broadcast monitor which is baseband. Can you select a baseband output?

I have one of these - s/n 3311 - and not had it powered in many years. Just switched it on and it works fine! The phase control has been sheared off and scale bulbs have gone but otherwise seems ok. Did you ever get a copy of the manual (as a pdf) as would be grateful of a copy.

It might have never been meant to compete, but rather to fill a requirement for a government tender.

RE: Capacitor quality. iC stands for Illinois Capacitor, previously Cornell Dubilier, and those are good name brand caps. It's the no name junk from Amazon you need to be wary of.

It looks like that raw DC input is negative (-)48 volts. The use of PNP transistors in the switching oscillator are another give away. In the USA -48 volts is the standard voltage in a telephone exchange. All telephone switch gear runs on -48 volts. A lot of IT gear from this era is the same. Perhaps Phillips wanted their product to be compatible with telephone exchange use? Also in the USA, before TV satellite links were popular, many areas of the nationwide network to local station distribution was via telephone company (AT&T) owned coax cable. So video signal monitoring gear would have been needed in some switching centers. The -48 volts is a battery voltage. The entire switching center ran off batteries which were float charged by AC line rectifiers or in the older days MG sets. Why have a positive ground electrical system? That was done to manage the corrosion and metal loss on buried cables. Search for more information if interested.

ESR

Спасибо, хорошая работа.

to reduce the signal gain to the correct level i assume you had a 75 ohm bnc load on the output from the video feed through

As a member of the German speaking engineering community, I must mention, that I never saw a CRT oscilloscope called an "Oszillograf". Not only is the "f" ending odd here (though correct), as the ph ending would be more common since a "graf" is a (royal) "count" (and -graph is the same as in English), but also that device would be called an "Oszilloskop" (or short "Oszi", speak in english: "oss-tseee"). I don't know why Phillips called it that way on the manual.

U get the best from this case.

Transparencies... I must be as old as you are. hehehe Nice instruments!

They're not called crapacitors for nothing. Happy you got it working reliably. Regarding testing the capacitors were you able to test them around the frequency of the oscillator? That could be where the problem lies.

The power supply inverter looks a lot like the standard Tektronix design and it needs some imbalance in the transistors V818 & V819 and some saturation of the transformer for the circuit to oscillate. This may be why the emitter resistors are different, as they depend on the individual transistor characteristics.

Hey mate, I used to sell those things for Phillip scientific industrial!!

I have found some time to look into HackTV and apparently when generating baseband video there is no filtering at all. However that can be done with software like sox. I've tried a "knife edge" 5MHz filter with it, and you get the ringing one expects. I'm currently getting an fl2k to VGA adapter and I think when combining that with sox and resampling to 140 MHz one should get a very acceptable signal with the aliases of the image being at >200 MHz where they can be filtered away easily.... This would also allow for interesting experiments. PAL is usually done over 5 MHz or more of bandwidth. How does it behave when you give it less. Theoretically it should be possible compensate the shift in hue from one sideband of the chroma carrier missing. Hoe does it behave in practice? Once I get my fl2k and have some time, I'll try it out.

I've seen a PM5544 circle pattern painted on a manhole cover in Jinan, China.

Any chance you could upload about 5 minutes of each of the test patterns you are able to generate? Thank you.

Hi what is your sony VCR model

I've never liked comb filters in TVs. They tend to soften the image far too much

I've long knew that you can mix synchronized composite feeds with essentially just a potentiometer, but it's still quite magical to see it happen live. It would be also nice to see it done purposefully wrong, on signals that can't be mixed. Like SECAM - and see how that would manifest on screen. I have an idea of what the result would be, I can also simulate that in software (or generate a "fake" SECAM signal on a Raspberry Pi or something) but seeing that done with real studio equipment would be something else ;)

End-to-end digital audio in the days of analog TV does sound rad indeed! What kind of link would such a signal be transmitted through? Coaxial cable? Microwave? ...fiber optic...? I can't really get the appeal of the original SiS for mono, though. Why not just modulate a 5.5/6/6.5 MHz subcarrier as for public broadcasts? In fact I'm mildly surprised that such a "baseband video with modulated audio subcarrier" signal was never really a thing - it would allow passing the entire TV signal down a single cable ;) - but I digress. I just don't fully get it - if the problem was avoiding a second cable, why engineer this elaborate sound-in-sync setup instead of just slapping on an FM or AM subcarrier? The fidelity wouldn't even be that far off considering that the original system was just 10-bit, what's that, 60 dB SNR? But of course, in the NICAM era it makes much more sense.

Just to update on my previous comment from 9 days ago: in Poland there was a similar situation, where the market was full of A2-capable sets, but the standard of choice for stereo on our TV was NICAM. Some people could make use of the A2 sets though, watching foreign channels on cable (or terrestrial near the borders). BTW, I'm pretty sure that Czechia and Slovakia used a variant of A2 as well. Also, given that in our D/K regions the A2 and NICAM carriers got placed _below_ the standard mono sound carrier, there actually was crosstalk with vision signal - but in reverse. One some sets, particularly older, single-standard ones, you could see the NICAM sound get interpreted as high frequency vision content. Anyway, to reiterate - you can get both NICAM and A2 concurrently on system D/K and I'd love to see how a modern set like this Samsung deals with that, whether all 4 available channels would show up. Maybe if I finally get myself a HackTV setup I could check it myself ;)

I thought that VSB was there to aid in demodulation, so that you could decode the signal by rectifying it, as least for the low frequency portion. SSB modulation requires synchronizing the phase, and SSB radio tuners (for audio, in amateur radio applications mostly) have a separate knob for dialing in that phase, which wouldn't be very practical. VSB makes it possible to infer that phase from the signal. Or that's what I thought at least, you're saying that it's just because of filter imperfections... I would also love to see the difference made by enabling and disabling the group delay compensation feature on an actual TV screen (or a capture setup, whatever). I suppose it'd probably be rather minuscule, but it would still be interesting to "pixel peep" into that.

NICAM and A2 actually *can* coexist with system D/K, or more specifically, so-called system D1 which was used in Poland and possibly some other former Eastern Bloc territories. System D1 retains the 6.5 MHz main FM audio carrier as for D/K, but limits the video bandwidth to 5 MHz as in B/G. That additional megahertz of bandwidth can be used for the second FM carrier for the A2 system at 6.258 MHz, and NICAM at 5.85 MHz (as for B/G and L). There are actually a couple of possible frequencies for the second A2 sound carrier for D/K, but that's the Polish frequency at least, and I'm pretty sure it was explicitly chosen so that both can coexist. Or... well, Polish Wikipedia suggests that A2 was apparently colloquially referred to as "Czech stereo", so the choice of subcarrier frequency may have actually come from the south 😅 A2 stereo was never actually broadcast terrestrially in Poland, the standard of choice for that was NICAM. But reportedly A2 soundtracks were passed through without re-encoding for some foreign channels in cable networks, much like SECAM color was not re-encoded for channels coming from e.g. Russia, even after all domestic TV switched over to PAL (and I vividly remember seeing Russian channels in black&white with SECAM subcarrier artifacts on my grandma's cable on her then-brand-new PAL-only set back in the day). So you needed a pretty multi-system TV to receive everything that there was on cable in both color and stereo. I don't think there was any channel that actually used A2 and NICAM concurrently, but it was technically possible and is documented as such in Polish sources. So you could in theory have 4 discrete audio channels (2 analog and 2 digital) on a single TV channel on Polish analog cable.

I once wrote a script that generated images which recreated of the Philips circle pattern (4:3) as closely as I could follow the original descriptions. Recently I found the PTV archive on Github and examined the EPROM data files and... while I (to my rejoice!) found that I got the pattern _really_ close, there were also a couple of differences. What surprised me the most is that the original is purposefully a little "blurry", or should I rather say - band-limited, especially in the chroma channels, leading to some clearly visible gradients like between the green and purple color bars. That of course makes sense for composite generators, considering that the chroma bandwidth is very limited anyway, but I heard that the original PM5544 along with some newer variants had component outputs, so an unfiltered, super-sharp chroma signal could make some sense for that, I guess?

While I can understand why you might want pro-grade hardware to generate an _analog_ test pattern, due to all the signal quality and genlocking issues you mentioned - what's really the point of all this expensive equipment for digital signals on digital TV? How will a digital test pattern generated by something like a PT5300 differ from just playing a video file or running a simple program on a PC or something like that?

Let's return to analogue television & put everyone on SECAM (very grim). Cheers!

PAL was developed as last, so it was technically better than SECAM and NTSC.

I'd attempted this with a consumer TV with an ST branded processor chip (STV2246H) that says it has PAL/NTSC/SECAM chroma demodulators, I added the necessary 3.58/4.43MHz crystals but it didn't seem to make a difference unfortunately.

There are some interesting tidbits that I find are missing from the video: mixing SECAM signals through demodulating and re-modulating color information is not only complex, it also degrades the quality of the resulting signal. For all those reasons, when complex mixing, digital on-screen graphics and things like that started becoming common on television (or perhaps even earlier), every single broadcaster in the world abandoned SECAM as a production format, if they ever used it for that purpose. Everyone operated as a PAL station and transcoded to SECAM just before transmission. It just made way more sense, while preserving the apparent advantages for the receiving audience. Although in practice, PAL usually provided better quality than SECAM nevertheless. As for the consumer equipment - yes, the right way to do OSD over a SECAM signal would be to use the keyed RGB signals in the SCART connector. But many consumer VCRs and satellite tuners just ignored that and mixed OSD (without any color subcarrier) in the composite domain as if it was PAL. The result was awful color trails behind OSD text, but people didn't really care all that much - you wouldn't keep the OSD on screen continuously anyway. Speaking of consumer VCRs, there are actually two ways of recording SECAM on VHS. The official method, used in France, involved separating the color subcarrier and then dividing it (by 4 if I recall correctly) as if it was a digital clock signal, and recording that (perhaps after filtering out the harmonics) as the color-under signal on videotape. That was arguably simpler than the heterodyne used for NTSC and PAL, but it was just something completely different, making it complicated to make a multi-system VCR. So Middle Eastern importers modded PAL VCRs so that they would treat SECAM signals as if it was PAL, heterodyning the color subcarriers. It was rather simple to make it work because PAL and SECAM color signals occupy roughly the same part of the composite signal spectrum. And that's how MESECAM (Middle Eastern SECAM) was born, which is a term specific to consumer VCRs, and despite the name was used not just in the Middle East but in Eastern Europe as well - basically in every SECAM country other than France, making French and Middle Eastern/Eastern European tapes incompatible. On the other hand, MESECAM VCRs could record and play PAL tapes just fine. What's arguably even weirder, encoding of SECAM was never defined for S-VHS, and all S-VHS VCRs in SECAM regions reportedly transcoded SECAM signals into PAL when recording.

South Korea was also the only non-PAL country to implement Zweikanalton/A2 stereo.

a switching power supply is actually pretty appropriate for a fully digital design such as this one. also, it has a much better efficiency than a old style linear PSU

if this can interest me? absoluetly and definitely a big YES. not only (in my case) for feeding a clean and big mustached secam, but also to record it on tape. i also spent some time restoring, and trynig to fix vcr of all kind. i have a hackRF, and this would be the greatest addition to turn it into an universal generator. i would even say if s-video output is possible, it would be nice :) i'll follow this project closely, for sure. and thanks for the time you spent on that.

Wow - thats great! I would sure like one - maybe a kickstarter project would be the way to test the market if you want to develop it further. Keep up the great work you are doing! Regards from Canada!

the successor to the OQ5506 sync generator is the SAA1043P

Those PALplus test transmissions are likely not from the BBC. When you watch the relevant YT video, you can see that it starts with a BBC-1 symbol, but that's mixing into the start of a programme. When the test transmission kicks in, that's a different recording from a different time and quite probably from Channel Four.

Any of this can be used to capture RF from a video tape player like in the VHS-decode project?

Amazing work! Definitely would be interested in this, got a bunch of CRT TVs to mess around with here!

I know there are some external clock inputs (10MHz) for hackrf and is one of the two coax ports near the usb port one that you need call CLKIN (P16)

Definitely an interesting project. i would sign-up for one if available.

At the end of 80's in Poland we had a lot of PAL tv's, especially from West Germany Sperrmüll 😊. Conversion into SECAM was done by added TDA3562A transcoder. PAL introduced @1995.

Interesting 😊