On 28.03.14 19:40, Surligas Manos wrote: > Which device did you used for receiving samples? I have noticed a same > phenomenon with my device, caused by a coarse implementation of a high > pass filter.
The filter in the Maxim2829 in the XCVR2450 that we used can be configured to 0, 100Hz and 30kHz and the default is 100Hz I believe? If you didn't change anything there this cannot explain your problem. Any filter than goes above 150kHz would be a problem for the centerish carriers in 802.11 OFDM (~300kHz carrier spacing). what happens if you TX a sinusoid and stepwise tune the RX to slightly off frequencies (take note of the *actual* RX LO frequency when doing the sweep - the difference to that one and the TX sinusoid matters). Does the RX power also start to decrease as soon as you set the TX-RX offset smaller than 150kHz? -paul PS: as Sebastian said, the outer subcarriers being lower can be explained by odd decimation factors like 5 - which causes the digital-downconversion filter chain to change to a single CIC stage I believe. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
