A new soft - and hardware version of the Raspberry Pi DVB-S transmitter:
Being able to generate almost any frequency with the Pi fractional dividers, I had to make a choice: get rid of the main 100 MHz oscillator, and replace it with the new clock signal I now have, or get rid of the 6 MHz symbolrate oscillator, and use the new clock for that.
As the exciter frequency is normally fixed (and mixed upwards), and a great variety of symbolrates are in use today, I decided to use the new programmable frequency for symbolrate.
ts2iq_pi, in its current incarnation of ts2iq_pi-10^-97.81.c, has now a command line option '-s symbolrate' (in k symbols per second). And it works! There is still a bit hardware left...
The question was also: will the frequency jitter created by not integer division to get the right symbolrate clock make decoding impossible? The answer seems to be that is does not matter much, but I guess you can always go to symbolrate 1000, 2500, etc for an integer divide. However test shows the Pi board revision 2 will not go much faster than 1900, it needs the time to encode the transport stream. If you overclock the Pi, I have not tried it, but then the derived clocks perhaps also change, and the math for symbolrate clock calculation may no longer be correct so there is a change it will no longer work, but you could change the clock frequency #define in the source.
Anyways, this is a first I think with command line settable symbolrate...