Bonjour Frédéric et bienvenue au UKVRR.
Thanks for the VHDL and ISE simulation results. I have been using Xilinx FPGAs since 1993, starting with XC3000 series.
This thread may be of interest.
https://www.vintage-radio.net/forum/...ad.php?t=55630
You may also be interested in some articles about standards conversion on my website. If you have any problems understanding the english I will try to help.