Hi David My experience with low SNR high PAPR OFDM systems , say around 3-4.5dB SNR requirement, is that the signal can be driven into a wall before the SNR reduction causes an issue- the spectral splatter is a big problem first before the SNR deteriorates to affect the performance...
But that depends on the behaviour of PAs. For PAs that exhibit a high degree of incidental phase when compressed heavily, that may upset it. glen. On 16/09/2015 9:57 AM, David Rowe wrote: > Thank you Helmut, nice to have independent verification of the SNR > estimation algorithm in the cohpsk modem. The MDS results are also > quite exciting! > > Would it be possible please to test the effect of FreeDV 700B SNR, when > the transmitter power amplifier is driven harder? On my simple tests > here, I couldn't drive my IC7200 hard enough to cause any problems, so I > am wondering where the limit is for 700B. > > For example if the peak/average ratio of the tx signal is 4 or 6dB, what > is the SNR degradation as measured by FreeDV 700B? > > Thanks, > > David > > On 15/09/15 22:59, Helmut wrote: >> Hi David, >> >> here the report of some tests this afternoon (sorry, screenshots can't be >> packed more w/o heavy quality reduction). Moreover I'm not sure whether the >> SNR on the FreeDV display is calibrated in dB. >> First I checked the 'me ------------------------------------------------------------------------------ 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
