Hi Stuart, Running the ADC/DAC at 16 kHz largely removes the need for analog anti-aliasing/reconstruction filters, significantly simplifying the hardware.
- David On 17/09/15 19:23, Stuart Longland wrote: > Hi all, > > Just looking at the source code, it hit me. When in analogue mode, we > run 16kHz sample rate, fair enough. > > But in DV mode, we sample the ADC at 16kHz, downconvert to 8kHz, pass it > through the modem and codec, then upconvert back to 16kHz for the DAC. > > We're dealing with voice frequencies, with SSB transmit bandwidths of > less than 3kHz. > > Why not do the whole lot at 8kHz and save some CPU time? Maybe some > rate-switching when in analogue or DV mode might be an option too, so we > run ADC/DAC at full-rate in analogue (for higher fidelity), then switch > to half-rate when we're doing DV. > > Regards, > > > > ------------------------------------------------------------------------------ > Monitor Your Dynamic Infrastructure at Any Scale With Datadog! > Get real-time metrics from all of your servers, apps and tools > in one place. > SourceForge users - Click here to start your Free Trial of Datadog now! > http://pubads.g.doubleclick.net/gampad/clk?id=241902991&iu=/4140 > > > > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Monitor Your Dynamic Infrastructure at Any Scale With Datadog! Get real-time metrics from all of your servers, apps and tools in one place. SourceForge users - Click here to start your Free Trial of Datadog now! http://pubads.g.doubleclick.net/gampad/clk?id=241902991&iu=/4140 _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
