Hi David
I've been across OFDM PAPR reduction development for many years.
Most successful simple schemes involve some sort of selective mapping or
bit flipping.
-IE the PAPR is computed and an alternative trajectory is generated .
-These can be either tweaking the source bitstream slightly (many methods)
-and also providing overmapping of the constellation (say 64 QAM points
might only map to 48 unique symbols, giving the system a choice of some
other point that can convey the same data.
-and also deliberate FEC violation (modify the most encoded code and
remove/reduce the offenders)
-and also selective bit flipping - easy and fast.
I would encourage some form of PAPR reduction for any ham OFDM development.
Without it, OFDM is often and (and ignorantly) overdriven creating
spectrum headaches for adjacent channel users
-glen
On 17/06/2020 07:33, David Rowe wrote:
Hello List,
I've been working with Peter, VK3RV on the surprisingly tricky problem
of measuring FreeDV Tx power.
Over the weekend I built an inline "sampler" and tried a few averaging
options to measure the power of a 700D waveform on my spec-an. I am
using my IC7200 with the drive adjusted so that the ALC just moves. I
am sampling the power between the IC7200 and my ATU, which is connected
to a dipole on 40M.
_______________________________________________
Freetel-codec2 mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
