At 08:49 AM 5/14/2008, kh6ty wrote: >The problem with MFSK16, as you found, is the mistuning tolerance. >For messaging, when there is a fast series of ARQ exchanges, if one >station has uncompensated offset between RX and TX (NBEMS must work >with untrained and inexperienced operators to be successful for >emcomm), and if the offset exceeds 4 Hz, which is not so unusual, >eventually it will not be possible to decode MFSK16, and therefore >the ARQ requests or confirmations may be missed.
Skip, One thing I have found is that when the sound card can be configured for a 12000 Hz sampling rate, the offsets are not present in most sound cards. It seems that when 11025 is used that the offsets are noticeable in many sound cards. I am not sure how an 8000 Hz sampling rate performs, but just thought I would mention this observation. 73, Mark N5RFX
