Re: [Discuss-gnuradio] DPSK Modulator and Demodulator

[Jason Uher]

>>> Hi,
>>>
>>> I am having trouble the the DBPSK mod and demod blocks. My flow graph is:
>>> file source -> DBPSKmod -> DBPSKdemod -> file sink
>>>
>>> If anyone knows why the output file of the whole graph would be 13 bytes
>>> or if I am missing something please let me know.
>>>
>>> Thanks,
>>> Dave
On Wed, Apr 21, 2010 at 9:46 PM, marcin_w <address@hidden> wrote:
>
> My mistake, i didn't realise you were using the available DBPSK block. The
> Packed to Unpacked block is already part of this Modulator, so disregard my
> comment.


Does the bpsk block you're using have some form of timing correction
in it? More than likely the data is being run through some sort of
filter (either explicitly or effectively) and the zeros at the
beginning are a warm up from the padding.

If you'd like the output to be 'nice' from a mathematical point of
view you will have to deconstruct the mod/demod blocks a little bit
and remove the timing correction stages and make sure that your
simulated channel does not introduce any timing corrections.

Jason