At 11:54 AM 2/17/2005 -0800, you wrote:
I realized about an hour before a demo last night that we didn't have
narrowband
FM (like ham and public safety), so I coded it up. Its in the
gnuradio-examples package, and it is commented rather liberally.
It will require an update on the gr-wxgui stuff too.
Love it - picked up the local noaa weather (162.4 here) wx right off.
I get some kind of strong 1Kz 'noise peak' that's pretty annoying, almost
a constant whistle - have no idea where it's coming from (maybe my
hardware) - it's on local police too.
Anyway, quick software mod: add a notch (comb) filter!
# notch filter, 1Khz at 16K sample rate
taps = [1] # original signal, no delay
for i in range(1,8): # .5mSec ( 1/2 cycle at 1Khz ) = 8/16000
taps = taps + [0]
taps = taps + [1] # signal delayed .5mSec cancels self at 1Khz
notch = gr.fir_filter_fff (1, taps)
then wire it in - end of problem.
--Chuck
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