Re: [Discuss-gnuradio] BPSK Demodulator (i.e. Receiver) Award/Challenge

[Thomas Schmid]

Hi Rene,

If you execute the benchmark_rx.py file with the following command:
python benchmark_rx.py --help

Then you will see that under "modulations" it says "dbpsk". The
demodulator itself is implemented somewhere else. You can find all the
different demodulation blocks in:
gnuradio-core/src/python/gnuradio/blks2impl. Here, you will find a
file called "dbpsk.py".

As was mentioned earlier, to make DBPSK into BPSK, just remove the
"self.diffenc", the differential decoder, from the connect method.

Now, even with this modification, you will most likely not be able to
communicate with your satellite. You will have to know a lot of
details on the communication protocol your satellite uses, packet
framing, etc., in addition to the right hardware and daughterboards.

Note that eventually, you will have to modify your GNU Radio
installation. Thus, it is almost impossible to evade knowing how to
code and to understand the working of GNU Radio. Just searching for
"BPSK" in files won't help you further...

Cheers,

Thomas

On Thu, May 7, 2009 at 1:46 AM, René Fléron <address@hidden> wrote:
>
> DBPSK is differential BPSK. However our transmitter sends 'ordinary' BPSK not
> the differential version, so I cannot use the DBPSK version.
>
> -René
>
>
> Josh Blum-2 wrote:
>>
>> The DBPSK blocks are in GRC under DPSK, there is a drop down to choose
>> between DBPSK, DQPSK, D8PSK. Also, see the packet encoder/decoder to
>> accompany the DPSK modulator blocks.
>>
>> A helpful example:
>> http://gnuradio.org/trac/browser/gnuradio/trunk/grc/examples/simple/dpsk_loopback.grc
>>
>> -Josh
>>
>> Jason Uher wrote:
>>>> I seriously doubt that making a regular BPSK receiver that goes
>>>> all-the-way,
>>>> i.e. recovers the transmitted data has ever been done. We haven't found
>>>> any
>>>> trace of anything be it commercial, research or DIY.
>>>
>>> Have you looked at the examples in the 'digital' folder?  The
>>> benchmark_rx and benchmark_tx do DBPSK, DQPSK, and others  'all the
>>> way', if you are set on BPSK you simply comment out the differential
>>> encoder/decoder in modulator/demodulator script.
>>>
>>>
>>> Jason
>>>
>>>
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>>
>>
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>>
>
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>
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-- 
"Don't complain; Just work harder" - Randy Pausch

Thomas Schmid, Ph.D. Candidate
Networked & Embedded Systems Laboratory (NESL)
University of California, Los Angeles (UCLA)