01-11-2017, 10:34 AM
(This post was last modified: 01-11-2017, 10:35 AM by ppppenguin.)
It's very likely that the RPI's PAL/NTSC coder is preset to those specific timings with little room for reprogramming.
Some years ago both David Robinson and I tried (separately and not known to each other until afterwards) to make an Analog Devices ADV7171 coder chip do NTSC405. It's fairly programmable, the subcarrier was no problem, but getting the H timings to work was a challenge. DR succeeded, I didn't.
Once you've got programmable logic available you can do just about anything. Darryl has amply demonstrated this with the Aurora range of converters. I knocked up a simple 625>405 converter using a Xilinx Spartan 2 series FPGA that was on a board designed for a client. Generating 240, 180 or any other standard would have been pretty simple too.
Some years ago both David Robinson and I tried (separately and not known to each other until afterwards) to make an Analog Devices ADV7171 coder chip do NTSC405. It's fairly programmable, the subcarrier was no problem, but getting the H timings to work was a challenge. DR succeeded, I didn't.
Once you've got programmable logic available you can do just about anything. Darryl has amply demonstrated this with the Aurora range of converters. I knocked up a simple 625>405 converter using a Xilinx Spartan 2 series FPGA that was on a board designed for a client. Generating 240, 180 or any other standard would have been pretty simple too.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
