Still working on this. It uses a XC9536 CPLD to link to a serial line, this chip has a built in UART, differential encoder/decoder and a manchester encoder and decoder. It just fits in a simple 36 block device but I am still battleing with the FM decoder which is to be as simple as possible. Favoured project is the DVB IP Gateway so this one has moved to the rear end of my priority list. (Sorry).