Tom, Matt, Robert, and others,
Thanks for the OFDM implementation; it looks very cool.
Unfortunately I'm having the same problems running
gnuradio-examples/python/ofdm/benchmark_ofdm_rx.py from the svn trunk.
I've attached a screenshot of benchmark_ofdm_tx.py as seen from
usrp_fft, and it looks reasonable.
My commmand lines:
./benchmark_ofdm_rx.py -v -R A -f 2.5e9
./benchmark_ofdm_tx.py -v -T A -f 2.5e9 --tx-amplitude=1000
(have also tried --tx-amplitude=10,100,500,2000,4000, and played with
--rx-gain at the receiver, and tried -f 2.45, -f 2.4 at both.)
USRPs Rev. 4.2 (circa 2006). I've tried both FLEX2400 and RFX2400/Rev
30 daughterboards. My transmitter and receiver are two feet away from
each other.
Program output:
$ ./benchmark_ofdm_rx.py -v -R A -f 2.5e9
OFDM Demodulator:
Modulation Type: bpsk
FFT length: 512
Occupied Tones: 200
CP length: 128
Warning: failed to enable realtime scheduling
gr_buffer::allocate_buffer: warning: tried to allocate
20 items of size 1600. Due to alignment requirements
64 were allocated. If this isn't OK, consider padding
your structure to a power-of-two bytes.
On this platform, our allocation granularity is 4096 bytes.
----
Any pointers or suggestions why this isn't working would be much
appreciated. Which daughterboards were used to develop/debug this?
Kyle Jamieson