In the UK, the BBC Radio 4 transmission on 198kHz is controlled by a rubidium frequency standard and thus is suitable for us as a off-the-air frequency standard. While developing the hardware to lock a 12.288Mhz crystal to the 198kHz carrier I've accidentally build a detector for the 25 bit/sec data that is phase modulated onto the carrier. See http://www.bbc.co.uk/rd/pubs/reports/1984-19.pdf for details of the modulation scheme and data formats. So, my question is... Does anyone have any PIC code for processing the detected bit stream to recover and check the date/time packets that I can use as a starting point ? I've seen code for MSF decoding (and I've written some myself) but this is a bit more difficult. Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist