The 'Hellcat MK I' 625-32 Converter.

Forum for discussion of electronic television. Generally, stuff to do with CRTs and not using mechanical displays.

The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Mon Jun 06, 2016 6:23 pm

Somewhere on this forum I'm sure I started a thread on this subject, but even using the features of the advanced search was unable to locate it - that's if it does actually exist. Should anyone trip across it I'll be interested to know of its existence.

Basically standard analogue 625 in, monochrome NBTVA 32-line out.

I've decided to continue with this as the hardware appears compete and it seems I'm someway into the software, so results should be reasonably rapid (says he).

It took a while to locate the hardware in amongst dozens of boxes, but it's seen the light of day for the first time in at least two years as a guess.

To jog memories a snapshot is below.

Steve A.
Attachments
Hellcat Mk I 1.jpg
Hellcat Mk I 1.jpg (257.83 KiB) Viewed 4997 times
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Harry Dalek » Tue Jun 07, 2016 3:53 pm

Steve Anderson wrote:Somewhere on this forum I'm sure I started a thread on this subject, but even using the features of the advanced search was unable to locate it - that's if it does actually exist. Should anyone trip across it I'll be interested to know of its existence.

Basically standard analogue 625 in, monochrome NBTVA 32-line out.

I've decided to continue with this as the hardware appears compete and it seems I'm someway into the software, so results should be reasonably rapid (says he).

It took a while to locate the hardware in amongst dozens of boxes, but it's seen the light of day for the first time in at least two years as a guess.

To jog memories a snapshot is below.

Steve A.


HI Steve
you mention it here
viewtopic.php?f=1&t=1756&p=15866&hilit=625+line+converter#p15866

and this is i think where you started it
viewtopic.php?f=1&t=1298&hilit=+Video+to+NBTV+converter

There you go a little help back at ya ~ :wink:
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4379
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Tue Jun 07, 2016 4:59 pm

Thanks Harry.

I've only quickly skimmed through it, it seems a bit thin on the ground regarding details. Though it does give me an idea of where I had got to. I'm at the stage of refreshing my failing memory and trying to work out what in the heck I was as far as the software goes. Although I like to think I'm quite disciplined when it comes to commenting code, sometimes my own comments defy me!

Thanks again Harry,

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Harry Dalek » Tue Jun 07, 2016 7:30 pm

Steve Anderson wrote:Thanks Harry.

I've only quickly skimmed through it, it seems a bit thin on the ground regarding details. Though it does give me an idea of where I had got to. I'm at the stage of refreshing my failing memory and trying to work out what in the heck I was as far as the software goes. Although I like to think I'm quite disciplined when it comes to commenting code, sometimes my own comments defy me!

Thanks again Harry,

Steve A.


No worries Steve ,I think every one here has the inventor in them and there never seems to be enough time for every thing so projects get put aside for the next idea to try and getting back to a past one is always hard.
I think you wanted to keep this one detail wise for the news letter ,i would put it on both less chance of both getting lost in the future .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4379
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Tue Jun 07, 2016 8:08 pm

Yes, I've had a couple of 'prods' from a certain Editor over the past year or so...wondering what's happened...gentle prods I might add. So having mentioned it to said Editor in the past I guess I'd better get on with it!!

I haven't mentioned the NBTV-625 Up Converter yet. Keep quiet guys.

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: The 'Hellcat MK I' 625-32 Converter.

Postby AncientBrit » Tue Jun 07, 2016 11:10 pm

Steve,

Nice to be appreciated for the quality of your articles.

'So much to do, so little time'

Cheers,

Graham
AncientBrit
Green padded cells are quite homely.
 
Posts: 858
Joined: Mon Mar 26, 2007 10:15 pm
Location: Billericay, UK

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Wed Jun 08, 2016 1:30 pm

AncientBrit wrote:...Nice to be appreciated for the quality of your articles....

I think said Editor is just trying to get contributions in rather than being concerned with the quality or otherwise.

So guys, help the poor Editor out...

Steve A.

I'm quite willing to help out in converting a fag-packet sketch into something a bit more presentable if that concerns one. Also to proof-read items too. No excuses now...
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Thu Jul 30, 2020 4:28 pm

Coming back to this after some four years - I'd better get on with it!

Probably the best known 625-NBTV 30-line converter was/is Peter Smith's version, in Newsletter Vol. 25 No. 3 sometime in the year 2000 - though it did do 32 line also.

It's still a valid design, though the fast 6-bit A-Ds are almost impossible to find these days. Very obsolete! (CA3306). Has there been any further articles regarding 625-NBTV conversion? I haven't come across any.

Finding a suitable replacement for the CA3306 isn't easy without opening your wallet wide. This is a hobby, not a research project! But I'll keep plugging away.

I have a number of CA3306 chips here, my plan is to use them first, get the system working with an eye on 8-bit video, and see what alternatives there are to replace the CA3306. There are a number of potential chips (all 8-bit). But until I crunch some numbers it's all open-ended.

**************************

The reason for this is I'm wanting to do the opposite, 32 to 625, but there are few sources of good and stable 32-line NBTV. I guess much like the SSTV-625 up-converter I did some years ago, I had to generate my own source files. The principal it uses is much the same but the data somewhat less per frame so it should be simpler. (He hopes).

Later...Though it would very easy to generate a static NBTV frame source, or even animate it. But I think a 'proper' 625-NBTV device would be useful on its own. A chicken and egg situation.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Harry Dalek » Thu Jul 30, 2020 5:12 pm

Lab guy mentioned to me there's a Philips sync generator chip 625 line out there.... if it helps cutting out a circuit you can program it to 7 tv standards philips-saa1101
https://dtsheet.com/doc/235442/philips-saa1101
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4379
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Thu Jul 30, 2020 5:50 pm

Thanks Harry, and Lab Guy too. I've seen that chip in the past some years ago, but it is what it is, just a SPG. The PIC I used in the previous SSTV-625 up-converter did all that plus read from the memory and outputted the data ready for a 625 D-A. As this is monochrome there's no requirement for a colour sub-carrier for composite, nor YUV or Y, Cr, Cb for component video. Though I have to confess I haven't done a 525/60Hz version...though most modern TVs will almost accept anything analogue. Mine even accepts SECAM! Egads!!

I wonder if it's still available? It is quite an older generation device, probably a 1980s chip. But thanks for the suggestion, it could well be useful to others...

Steve A.

Though I must admit SECAM on 525 would be interesting! Maybe not.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand

Re: The 'Hellcat MK I' 625-32 Converter.

Postby Steve Anderson » Fri Jul 31, 2020 4:58 pm

Somewhere, some time back I did knock up an equivalent device for this using a PIC micro for 625/50 but only for monochrome. No 7.8kHz output for PAL sub-carrier phase switching for example. I think I squeezed it into a 14-pin device...I'll have a dig around...it wouldn't be hard to re-do if I can't find the old version. Either would be fine for monochrome or component video (YUV or Y, Pb, Pr).

Steve A.
User avatar
Steve Anderson
"Fester! Don't do that to 'Thing'"
 
Posts: 4143
Joined: Fri Mar 30, 2007 10:54 pm
Location: Bangkok, Thailand


Return to Electronic NBTV

Who is online

Users browsing this forum: No registered users and 0 guests