Re: [Discuss-gnuradio] multiple reception simultaneously

[Martin Braun]

On Wed, Feb 09, 2011 at 10:03:41AM +0530, ranjini ram wrote:
> Hi,
> i am trying if its possible to do reception of FM signals at the same time and
> produce the output at the same instant in different loudspeakers.i mean 
> whether
> its possible to tune to multiple FM channels at the same time and hear those
> channels at mutlipe output simultaneously.i also want to try this out in video
> signals.but i found that colour decoding is a tedious task.i am new to this

Depends on what kind of hardware you have. The simplest way--and using
only one USRP--is to increase the incoming bandwidth, and select the
individual channels by a decimating, and frequency x-lating, filter.
Then you send those signals through parallel demodulators und dump the
result on an audio sink each (from your question, I'm assuming you have
two soundcards). Or you could put one station on the left and one on the
right speaker by using different inputs of one audio sink.

This is less computationally intensive if the stations are close
together. Say you have one station at 100MHz and one at 101MHz, simply
tune to 100.5MHz, sample at 2MS/s and yank a 200kHz section at
+/-500kHz offset each; then pass that to the FM demodulator.

If you're new to GR, definitely use gnuradio-companion.

MB
-- 
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

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