Being rather pleased with myself at having moved my nasty software manchester codec routine into hardware in some spare cpld capacity,I was alarmed to find the the codec was generating lots of sync signals but I could not find any valid decoded data.It was at 2 this morning that I re-read the radio tranceiever data sheet and found that if you use the 60Khz IF option as I had then the data output is inverted.So it does save a lot of late nights sometime just to make sure that you do really know what you are doing.