I see in the FSK code that "Sample freq must be divisible by symbol rate". I don't know if the PSK modems are similarly impacted, but:
8000 / 750 = 10.6666... (ouch) 48000 / 750 = 64 (ahh :) It's been my experience (anecdotal though it may be) that sound cards prefer working at the higher sample rates anyway. Running all our modems at 48000 helps with that and gives us internal consistency, but there are some potential drawbacks: - This could impact the complexity for the STM platform in the SM1000. - There are plenty of sound cards out there that top out at 44100, so some resampling would still have to occur there too. Of course, any artifacting on that would likely be far enough up the spectrum that it wouldn't be noticable in what we're doing. Even so, running from 48000 back down to 8000 is also a much nicer divisor. 73 de Kevin N8VNR (reposted from the correct source address) On 02/03/2017 10:20 AM, Helmut wrote: > Well, maybe that’s the reason. I already wonder about a modem sampling > rate of 7500 Hz, as today’s most audio applications are using integer > divisors/multipliers of 48000 Hz. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
