Hi Steve, Codec 2 has a 5 bit energy quantiser which is scaled to expect numbers in the +/- 32767 range.
The fdmdv demodulator however is truly "floating point", it doesn't have any internal references to fixed levels. So it should work at really low levels and not need an AGC. This is an interesting example of digital versus analog. The human ear "likes" speech in a certain range for comfort, but the modem doesn't really care. Actually I switch off AGC on the HF receiver when I use FreeDV, as it makes the signal bob around too much on the displays. Cheers, David On 18/10/14 02:22, Steve wrote: > It's too bad C can't de-reference a void pointer to a data type, as you > could just swap all the short[] references to void[] and then > de-reference as to what was being used (too Java I know... ha). > > Maybe the best thing would be to just make the codec2 a floating point > vocoder. Maybe change it internally to +/- 1.0 maximum. > > Then the interface person would make whatever wrapper they need to get > to that. > > Interestingly, the codec doesn't work at +/- 1.0 limits, and needs +/- > 32767.0. I never looked farther as to why. Just went with the flow... > > Steve > > > > ------------------------------------------------------------------------------ > Comprehensive Server Monitoring with Site24x7. > Monitor 10 servers for $9/Month. > Get alerted through email, SMS, voice calls or mobile push notifications. > Take corrective actions from your mobile device. > http://p.sf.net/sfu/Zoho > > > > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Comprehensive Server Monitoring with Site24x7. Monitor 10 servers for $9/Month. Get alerted through email, SMS, voice calls or mobile push notifications. Take corrective actions from your mobile device. http://p.sf.net/sfu/Zoho _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
