Standards converter for "new" sets

[murphyv310]

Originally Posted by dominicbeesley

Thanks for the reply, - 4 static pages is great for test / demo but not something you'd actually go and use on a daily basis.

Cheers

Dom

You can programme new text pages quite easily with a windows pc why dont you look at RT Russells web site.
Trevor

[Andy Green]

Well I would be interested in a teletext insertion widget - I don't think there is an easy way to use Richard Russel's test card gen with live video, at least not without reverse engineering it to some extent!
Following on the 'What if.....' theme of 405 line NTSC, how about 819 Line SECAM or 405/819 line teletext? Kat? Dominic? Trevor et al?

[arjoll]

Has anyone googled "teletext inserter"?

There are a lot of solutions there, although I'm sure the pricing of some of them may put them a little out of reach (e.g. there's one there which consists of an HP Proliant DL360 server with inserter card, or this option for only 2200 euros!).

[David_Robinson]

Originally Posted by ppppenguin

The MPU would format the data stream and send it to the FPGA. the FPGA would store the data stream in its internal RAM, serialise it put it on the right lines and add the teletext preamble etc. Also need a small amount of analogue circuitry to insert the text into the video.

Even simpler, use a DAC with built-in teletext insertion facility, e.g. Analog Devices ADV7171 and many others, also many Philips types.

[dominicbeesley]

ppppenguin: Thanks for the offer of a photocopy I've now sourced a copy of this document online. The BBC fpga programmer is certainly _not_ a joke see: http://www.sprow.co.uk/fpgas/index.htm. The VHDL will be compiled on a modern machine, the electrical interfacing probably will hang out of the backside of a BBC, connected via RS423 to a linux box to download files from my LAN. (My workshop internet access is currently lynx running on linux viewed on a BBC).

murphyv310: The RT Russell thing, yes its great. But I want _useful_ teletext I can get quite bored of 4 static pages of 40x24 really quickly. The gadget I'd like to build would give potentially 1000's of pages downloaded from the net for me to browse at leisure. Also I'd want to be able to overlay this onto any live video source. If I thought I was up to it I'd even think of making it wireless and update itself from t'internet automagically but alas I think that is pushing my schoolboy electronics a bit far.

David_Robinson: The insertion of teletext itself isn't really the question (a few discrete components can do that bit) What I was after was a teletext encoder (sorry badly worded original question). I've now got some documentation and will report back at some point later on progress.

arjoll: <tongue location="cheek">The UK government has decided that videotext is now BAD FOR US - it being a British Invention - it should be denied and forgotten and quickly replaced with something that looks better and shinier and is incabable of delivering news to people who would like to read!</>

Thanks all for the replies. I'll see how I get on now the nights are closing in....might be a while though a very nice fellow forum user donated an old computer and a few bits of test gear so I'm sure I'll get distracted by those for a few evenings....

Dom

[ppppenguin]

Originally Posted by dominicbeesley

ppppenguin: Thanks for the offer of a photocopy I've now sourced a copy of this document online. The BBC fpga programmer is certainly _not_ a joke see: http://www.sprow.co.uk/fpgas/index.htm. The VHDL will be compiled on a modern machine, the electrical interfacing probably will hang out of the backside of a BBC, connected via RS423 to a linux box to download files from my LAN. (My workshop internet access is currently lynx running on linux viewed on a BBC).

If you've got a machine readable copy of the teletext spec could you publish the URL so that we can all see it. It may be a later version than my copy. It will certainly be more legible!

I've looked at the BBC micro project and I just don't see the point. The schematic of the Xilinx Parallel III programming probe has been published and only has a handful of common parts in it. The software to use it is built into all the Xilinx packages. If you can't find the schematic of the Parallel III probe I'll send you a copy. Also that BBC micro project was designed in the days of the 4000 series Xilinx. These are long obsolete and while the programming method (slave serial) is still valid the file sizes have increased by a few orders of magnitude for modern devices. You can get very bored waiting for a program to download to the device.

My current (work) project is using a XC3S1400A and I'll definitely be getting one of the USB programming probes since my Parallel III will be horribly slow for that relatively large device.

[dominicbeesley]

Ah,, now how to explain.....the point _is_ the pointless, to use something improbable to acheive the pointless........I'm a masochist! I want it to be difficult!

anyways found the spec at http://www.doc.ic.ac.uk/~ih/teaching...-spec/spec.doc not sure its that up to date but is probably enough to get going. If yours is more recent (or even different but older) I'd love a peek

Cheers

Dom

[ppppenguin]

That document is the same as the one I've got. Nice to have a decent machine readable copy though strange to save a series of scans as a Word document. I converted it to a PDF which seems more sensible.

[gordygreytop]

Just found this link
http://xpcatv.en.alibaba.com/product...l_RNO3003.html

[Andy Green]

This is a QUAM modulator for digital TVsignal generation, not really anything that would be of any use in producing pictures for analogue sets,