Hi Bruce, Your point re a narrowband interferer, like a "birdie" at HF, is a good one. It would be good to "instrument" our modem code to record the bit error patterns off real channels so we can tune the whole system to deal with these sorts of effects.
Cheers, David On Thu, 2012-02-16 at 17:11 -0800, Bruce Perens wrote: > David, > > Really clever. So, the effect of an error is that you potentially lose > bits rather than the whole frame, and you stay synched for the next > frame. > > The downside, I guess, is that in the case of narrowband noise, you > lose the same bits from one frame to the next. But you could > 1. Send two frames per symbol, and only one per pair would be subject > to the noise. > 2. Alternate the bit distribution pattern, but then you'd have to sync > to that. > > Thanks > > Bruce > > On 02/16/2012 04:39 PM, David Rowe wrote: > > Peter Martinez suggested making the frame period the same as the PSK symbol > > period. For example the 1500 bit/s mode would have 60 carriers at 25 bit/s > > (40 ms symbol period). The advantage of this mode is no frame sync > > overhead is reqd. > > > > ------------------------------------------------------------------------------ > Virtualization & Cloud Management Using Capacity Planning > Cloud computing makes use of virtualization - but cloud computing > also focuses on allowing computing to be delivered as a service. > http://www.accelacomm.com/jaw/sfnl/114/51521223/ > _______________________________________________ Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
