Ultra V1770 - my first telly and Im struggling

[ppppenguin]

Well done with using your generator like that. No need to worry about interlace for getting the set going. If you generate 202 or 203 lines, progressive scan, 50Hz field, it will work just fine. The only thing you won't be testing is how well the sync separator is dealing with interlace.

[Exiled Yorkshireman]

Thanks Mike and Jeffrey. Now that I've figured out the basics of arb waveform creation there's no reason why I can't create ones for checking geometry etc. But that'll happen after I've got the tuner working.

[Mike Watterson]

Well done with using your generator like that. No need to worry about interlace for getting the set going. If you generate 202 or 203 lines, progressive scan, 50Hz field, it will work just fine. The only thing you won't be testing is how well the sync separator is dealing with interlace.

I'd wondered about that, but having never done it... There was 405 TX still in 1972!

The 405 only sets still popular then as bedroom sets because not much extra on BBC 2. Colour was still not universal even for 1st sets, though we had a colour set then. I had one 405 set in our Kitchen for a while. I'd get them free, fix them (ineptly) and sell in Belfast Telegraph Classifieds as BBC1/ITV only bedroom etc sets.

Edit: Of course back then it was reasonable on dual standard models to remove knob/lever and solder contacts on the big switch in 625 position. Sometimes two switches: the IF /Video/Audio one side and timebases /frame/line/LOPT on the other.

[Mike Watterson]

Thanks Mike and Jeffrey. Now that I've figured out the basics of arb waveform creation there's no reason why I can't create ones for checking geometry etc. But that'll happen after I've got the tuner working.

Also in 1970s there was still a lot of testcard transmission time!
I can see modern ones on a couple of RTE NL DTT and KaSat "test" channels, with the moving bar so you know it's running (MPEG), but now the only "Geometry" settings are aspect ratio. Though I maybe have a 6" 625 and 6" 525 mono set and a JVC 2" TV/Radio (Tuner dead on UHF, but BandI & III works) all CRT.

[Exiled Yorkshireman]

So... I downloaded a jpeg photo of test card C, and wrote a Python program (about 65 lines of code) to generate a csv file from it including h and v sync for upload to the Siglent arb. The waveform is not interlaced, but identical fields at 50 Hz. I've attached a photo of the  result (with the usual shutter effects).  There are problems at the top of the screen and the whole image seems to be shifted left. Other discontinuities are more likely to do with the jpeg size.

Still, it's progress and proves it can be done with an arbitrary waveform generator.

   

[Mike Watterson]

Fantastic!
The magic of DDS.

A longer shutter time and bigger f-Stop gets rid of the shading. I've forgotten, but probably Jeffrey knows.

[Exiled Yorkshireman]

Fantastic!
The magic of DDS.

A longer shutter time and bigger f-Stop gets rid of the shading. I've forgotten, but probably Jeffrey knows.

Yes, longer shutter time and smaller aperture. To be honest, I couldn't be bothered to set up the DSLR, so I just used my phone. Apologies for that,

[Exiled Yorkshireman]

Well, I think I've finally nailed the arbitrary waveform generation. I now have a Python program which will convert any jpeg to a waveform displayable on a 405-line set, interlacing  and half-lines included.  Sync is absolutely rock-solid. I finally got a round tuit and dug out the Nikon and tripod. Exposure 1/5 second  f/7.1 ISO 100.

As you can see, the picture needs centering, but I'm not too unhappy with it.

Next stop, the tuner.

Cheers,
Steve

[ppppenguin]

I'm impressed. Both with your work on converting the JPG file and the capabilities of the arb. Something still looks wrong with interlace though it's hard to say exactly what. May just be line pairing in the sync separator.

Good photography too. Recently I've been trying to get some off screen photos with my phone (Samsung S22) and I can't see a way to avoid a frame bar. Keeping stray light from a screen is a problem whatever camera you're using.

[Exiled Yorkshireman]

Thanks Jeffrey. I'll take a look at the arb video waveform on the scope to check that the interlace is working as expected. It's entirely possible that I screwed up the timing a tad.I'm afraid that it's several decades since I last saw a live 405-line image, so I'll take your word for it that it's not quite right. My waveform is using 100nS data points. I could make them shorter if required.

Would it be possible for you to explain 'line pairing'? There is so much that I'm not familiar with yet...

As far as phone photography is concerned, mine's an iPhone so Im not familiar with the S22. I did find the following guide to setting shutter speed on the S22 though:

https://www.howtogeek.com/784541/how-to-...axy-phone/

I took that shot with the room lights off and the camera mounted on a tripod, and for good images you'd need to do the same.