Psk modulation

GNU Radio
1

Hi everyone,
I am trying to do a PSK-Modulation. For that i use the dpsk-block and
choose
dbpsk which should be the same as psk-modulation. I connect the USRP
with a
oscilloscope, but i didn’t get the expected output.
I tried to set the input vector to 127,127…127 and 0,1,0,1…0,1 but
i
either didn’t get a good output.
Where is my mistake? Please help, thank you.

http://old.nabble.com/file/p29160823/psk.grc psk.grc

the output for the vector 0,1…0,1 is this:

http://old.nabble.com/file/p29160823/tek0062.jpg tek0062.jpg

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2

On Wed, Jul 14, 2010 at 7:20 AM, EsserIHF [email protected]
wrote:

the output for the vector 0,1…0,1 is this:

http://old.nabble.com/file/p29160823/tek0062.jpg tek0062.jpg

Have you tried running benchmark_tx.py in
gnuradio-examples/python/digital?

You can use that as a reference for how to use the modulator.

Tom

3

Yesterday I looked in this example. I let this example run with the
parameters “-m dbpsk -f 20000”,so the example should do the modulation.
But
on my scope, I still can’t see a good modulated signal. Here is the
output:
http://old.nabble.com/file/p29169627/dbpsk.png dbpsk.png
Can someone explain to me why I didn’t get the right output? Thank you

Tom R. wrote:

I tried to set the input vector to 127,127…127 and 0,1,0,1…0,1 but

Discuss-gnuradio Info Page

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4

I think my problem has something to do with the parameters of the USRP.
I now
try to send a file modulated with DBPSK. So I build a graph
File source → Packet Encoder → DPBSK MOD → DPBSK DEMOD → Packet
Decoder
→ File sink
and i really get the correct output file. Here the grc:
http://old.nabble.com/file/p29170637/top_block.py top_block.py
If I put a USRP source and USRP sink into graph, I don’t receive
anything.
Not even one byte. Here the grc:
http://old.nabble.com/file/p29170637/top_block.py top_block.py
I hope anyone can help me. Thanks

EsserIHF wrote:

i
Have you tried running benchmark_tx.py in

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