At 04:41 PM 12/12/2006, Roger Grady wrote: >Sounds like very weak packet bursts to me.
I looked at the sample with a waveform editor (Audacity) - there's definitely data riding on the 100Hz tone, at around 5-10% of the 100Hz deviation. It looks like it continues during the DTMF bursts also but it's hard to tell for sure visually. The data looks like two-tone, low tone is probably 1300, high tone between 2000-2100. The higher frequency is harder to measure because there aren't as many cycles of it in a row as the lower. The data appears to start with a pilot of 7 cycles of low tone, followed by 2 cycles of high tone, the pilot lasts for just under 180ms. After the 3rd DTMF burst, there's another 50ms burst of something more complex. It may be a continuation of or another DTMF burst, coupled with the two-tone data but the overall level of the signal is higher, and the two-tone is much much higher than before. All in all, an interesting signal. I hope somebody recognizes it as it's got my curiousity aroused. Roger Grady K9OPO
