Is Communication chain correct?

I want to set up a communication chain. what I do is :
Vector source --> Framing --> DBPSK modulation --> DBPS demodulation -->
char_to_float --> simple_correlator --> vector sink.

but what I have in the vector sink is nothing. vector is an empty
vector,
while I know that the input of correlator is stream of bits but its out
put
is nothing.
what can be the problem?
the code is uploaded.
http://www.nabble.com/file/p17986270/testsourcesink.py testsourcesink.py

thanks,
Mehdi

View this message in context:
http://www.nabble.com/is-Communication-chain-correct--tp17986270p17986270.html
Sent from the GnuRadio mailing list archive at Nabble.com.

On Wed, Jun 18, 2008 at 09:28:55AM -0700, mehdimolu wrote:

http://www.nabble.com/file/p17986270/testsourcesink.py testsourcesink.py

thanks,
Mehdi

Mehdi,

Typically we debug these kind of thing by logging intermediate results
to files (using gr.file_sink), and then look at the resulting files
using octave or matplotlib. There are tools in gr-utils/src/python
(which get installed in ${prefix}/bin) and .m files in
gnuradio-core/src/utils which may be useful.

Many of the examples and the implementations in blks2impl have
extensive logging which may be enabled. Please take a look at those
to see the basic pattern.

Eric