120 and 180 line viewing

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

Re: 120 and 180 line viewing

Postby Steve Anderson » Fri Aug 12, 2022 3:26 pm

GrantXTV wrote: it is a far better to generate a video signals than working with wav files.


I find that surprising...I'd rather work with simple (and they are simple though often large) .wav files than design/build a VGA display device. Even a 'simple' 640x480 display requires quite fast timings and therefore fast logic. When you get to 1000 pixels and beyond it's crazy. In the background I'm working on such a device simply because TVs and monitors with a 625/525 analogue inputs are becoming rarer as time goes on, either composite (PAL/NTSC) or component (YUV). I recently bought a Philips PC monitor, it only has a HDMI input, nothing else, no VGA, no DVI, that's it - HDMI or nothing! I think our main 'TV' might be the same, I'm not sure without looking, its only input is the set-top box from the incoming fibre...oh! and wi-fi, also off the same fibre...

Steve A.
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Re: 120 and 180 line viewing

Postby Steve Anderson » Fri Aug 12, 2022 4:40 pm

For those interested in developing your own PC monitor interface, here is the ultimate 'chapter and verse' on the subject..

But make sure your monitor supports whatever standard you choose. Some manufacturers are more than a little vague about what standards their monitors support...and this is dated in 2013, some nine years ago!

Steve A.
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VESA-Display Standards.pdf
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Re: 120 and 180 line viewing

Postby GrantXTV » Fri Aug 12, 2022 11:27 pm

I have been testing the USB to VGA device I got yesterday, It is a U244-001-VGA made by Tripp Lite, here is the file attached.

It work without any issues within Ubuntu, but it has very limited amount of video memory, at the lowest setting of 640 x 480 at 75 Hz it works well and therefore I should be able to divide down to the sizes I am looking for, such as:
320 x 240 x 25
160 x 120 x 12.5
80 x 60 x 12.5

I have down loaded the display standards, I will go through them and start to do a design for my VGA to NBTV scan convert project, once this is done I will have a video signal to work with.
Attachments
Tripp-Lite-Owners-Manual.pdf
Tripp Lite USB to VGA
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Re: 120 and 180 line viewing

Postby Harry Dalek » Sun Aug 14, 2022 10:45 am

GrantXTV wrote:I have been testing the USB to VGA device I got yesterday, It is a U244-001-VGA made by Tripp Lite, here is the file attached.

It work without any issues within Ubuntu, but it has very limited amount of video memory, at the lowest setting of 640 x 480 at 75 Hz it works well and therefore I should be able to divide down to the sizes I am looking for, such as:
320 x 240 x 25
160 x 120 x 12.5
80 x 60 x 12.5

I have down loaded the display standards, I will go through them and start to do a design for my VGA to NBTV scan convert project, once this is done I will have a video signal to work with.


Very good hope it go's well Grant watching with interest !
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.
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Re: 120 and 180 line viewing

Postby GrantXTV » Fri Aug 26, 2022 9:23 am

It is going to take some time to build, as I have started doing the circuit layout and I am up to 28 integrated circuits on a four layer board, so I need to rework the design somewhat. As it is basically a RGB frame store, using three memory blocks in two parts and a scan converter driven via FPGA connected to a USB port. Part of the high IC count is the R-Y Y B-Y and the V/H sync analog input / output interface, which is somewhat important to have with electronic equipment connected. Providing for a VGA in at 640 x 480 x 75, with analog out with five RCA connectors, another five for the input side and with USB out for a computer interface.
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Re: 120 and 180 line viewing

Postby victorliu » Tue Nov 22, 2022 3:48 pm

I need to implement a basic High-Speed USB host interface for my Spartan-6 FPGA.
I can not get to know which solution would be convenient for me.
How many FPGA resources would I need in each case?
https://www.icdrex.com/supplier/amd-xilinx/spartan-6-fpga/

You need to develop an analog-to-digital interface for the VGA, probably something capable of varying rates requiring a variable clock as well.
You'll probably want an FPGA or CPLD to coordinate everything.
https://www.icdrex.com/product/epm7032aetc44-10n/
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Re: 120 and 180 line viewing

Postby GrantXTV » Mon May 15, 2023 10:52 am

Hi All,

I have not been on much, as there has been so many other thing keeping me busy, here is a bit of an update on my NBTV project.

I put together a basic program to test out different ways of doing video compression, whereby I read in a video file and convert it to RGB, then RGB back to video. With the gap in between to plug in software models for different experiments to see what works and what does not work, before I send out the bit stream to the modulator for extra processing. The aim is to go with a hybrid approach that is both digital and analog or somewhere in between. The first stage is the digital compressing that has a image frame (I) fixed image and a predicted picture (P) made up of parts of each frame from image on each side. Since I am using analog modulation 65536QAM, or just QAM for short (video and sound), plus MFSK (data channel), therefore it is not possible to send any forward error correction (FEC), so the digital compression needs to work with noise, therefore I making fill use of noise reduction and analog compression / expansion in the modulator and demodulation sections.

As for the hardware design, I am now working on a new modulator using ADC,DAC,FPGA and SRAM, as lot of the processing is now done in software, make this a lot simpler task to do. This is still very much a multi-year project as I am working it out as I go, here a image of version one software interface.

download/file.php?mode=view&id=16315

Progress is been made, but very slowly
Attachments
NBTV_image_v1.png
Software interface for Linux, video is at 120 x 96 x 12.5
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Re: 120 and 180 line viewing

Postby nabeellateef » Wed Jun 14, 2023 3:57 pm

I had to cut this out of a message that was dubious...

"Wow, this is a very wonderful article, my sister loves to peruse such kind of post, I am going to advise her and bookmark this site page. Much appreciated..."

You're welcome...Steve A....

Without researching the links provided I've deleted them. They don't appear to pertain to anything NBTV or image-related in any way...keep it on-topic...however, we still look forward to your on-topic imaging contributions...

Steve A.
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