Replace the low pass filter with a band pass filter. The low pass filter is
not extracting the signal at the center frequency, but the first 70KHz of the
1MHz bandwidth. Also, the decimation and interpolation chosen in the resampler
will destroy all information in the channel. At the chosen values, the
interpolation would be essentially inventing the signal, rather than upsampling
it.
Regards,
Mark McCarron
Date: Fri, 24 May 2013 15:40:39 -0700
From: alankeithwoodw...@gmail.com
To: Discuss-gnuradio@gnu.org
Subject: [Discuss-gnuradio] Noise levels from a RTL dongle
Hi,
I am new to Gnu radio but have it working on Mac OS X 10.8 and am using a E4000
tuner in a usb dongle. I have been experimenting with a Gqrx as well as GRC
and am getting mixed results, with Gqrx I can get reasonable quality FM
reception on 89.31 Mhz (radio 2 in the UK) with the wide band FM (mono)
receiver and a 70Khz filter band. I have tried to replicate this in GRC as I
want access to the demodulated signal as a live file (to be fed into a std unix
pipe) for onward processing, however, the quality is significantly worse than
Gqrx. Can anyone help with my GRC graph.
Details are on my site, Woodstercorp.com
Any help gratefully received.
Alan
View this message in context: Noise levels from a RTL dongle
Sent from the GnuRadio mailing list archive at Nabble.com.
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