IIRC Alfred has a custom SDR, so the connection between his radio and the FreeDV API is software - floating point samples. This is an interesting interface and may be related to the inaccurate SNR measures he is getting.
It is also an interesting pointer to the future. FreeDV can be fed samples directly from the ADC or digital down converter. No "gain" or AGC is required. If you feed the FreeDV API samples scaled by 0.0001 or 10000 it will work exactly the same. Much of the signal processing chain we use for SSB is going to evaporate in the next few years. Cheers, David On 03/09/15 05:54, Walter Holmes wrote: > Alfred, > > Just for a point of reference, how are you connected to your radio? > > Ie.. are you USB, LAN cable, or via a digital interface of some kind? > > I am using an HPSDR radio attaching to my radio via a LAN cable, and I have > heard from others as well that are USB attached that they saw an increase in > CPU in the 700/700b modes. > > But I do not see that increase at all in my environment. > > Thanks, > > Walter/K5WH > > -----Original Message----- > From: wully [mailto:[email protected]] > Sent: Wednesday, September 02, 2015 1:59 PM > To: [email protected] > Subject: [Freetel-codec2] 700B mode seems to use much more cpu cycles in rx > than the 1600mode > > Hi > > I am experimenting further with the 700B mode. It seems that this mode uses > quite a bit of cpu cycles during rx, substantially more than the > 1600 mode. I am using a relatively slow cpu, which runs my sdr code at about > 20-25% cpu in SSB, when I switch to 700B rx, the cpu increases to about > 45-50%. > > I assume, that the 700B makes extensive calculations? > > > Question about SNR-estimation: > > I just display the value codec2snr that I get from calling > > int codec2sync; > float codec2snr; > > freedv_get_modem_stats(freedvRx,&codec2sync,&codec2snr); > > What are the typical values that should appear? > > Thanks > Alfred, hb9epu > > > > ---------------------------------------------------------------------------- > -- > 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 > ------------------------------------------------------------------------------ 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
