RTL2832U FIR filter

Francesco Gugliuzza f.gugliuzza at hacklabproject.org
Sun Jul 15 10:40:33 UTC 2012


2012/7/15 Michael Karcher <osmosdr at mkarcher.dialup.fu-berlin.de>:
> Good point, but actually, I am sure it is not an effect of the tuner
> output filter. My USB stick contains a fc0012 tuner, which is always set
> to 6MHz bandwidth. The bandwidth of the suspected anti-alias filter
> changes clearly when I change the sample rate, though, on the other
> hand, if I manipulate the FIR coefficients to contain sharp dips in the
> range of hundred kHz, the dip position does not change when I change the
> sample rate. This makes me cofident that the suspected anti-alias filter
> has to be located in or after the resampling unit.
The only thing I can think of now is the raised cosine filter used in
digital modulation receivers, but IMHO that should be implemented in
the FIR filter.

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Francesco Gugliuzza
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