Hi Steve, Can't recall exactly but I guess it was chosen to get the bit rate I needed for the codec. Minimising carriers is best, to minimise bandwidth, allowing more room for FEZC or diversity.
Sure, any choice of pilot symbol value is probably OK. Cheers, David On 26/02/17 18:39, Steve wrote: > I was experimenting with the number of carriers (8 versus 7) on the > coherent modem yesterday, and it seemed to work well. > > I was wondering how the number 7 was decided on, as it seems like an odd > number. > > For example, for my purposes, it will be simplified to have 32-bits > every baud. I didn't know how to change the pilots so I just added some > opposite to the end: > > 1.000000, -1.000000, 1.000000, -1.000000, 1.000000, -1.000000, > -1.000000, 1.000000 > > -1.000000, 1.000000, 1.000000, -1.000000, 1.000000, 1.000000, 1.000000, > -1.000000 > > The 32-bits also gives you another 4-bits at the vocoder, so you can use > 1-bit for text and expand something else by 3 bits, or just have 4-bits > for text. 800 bit/s versus 700. > > 73, Steve/k5okc > > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > > > > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
