James Moritz wrote:

you would need 17 tones - then in the example it would be 13+16 mod 17 =
12; perhaps this is something like what Stuart is suggesting?

Dear Jim and the group,

 exactly, with 17 tones, taking into account the sign as indicator
of 'wraparound', it is possible to encode the 16 deltas, with the
modulo operator. This is the alternate scheme.
It seems that the consensus is on reducing the bandwidth.
So please Johan, wait a little before modifying the PIC code that
drives the DDS...

Thanks for your input

73  Alberto  I2PHD