Re: [Discuss-gnuradio] Two GMSK decoders with two msg queues

[Dawei Shen]

Hey, Michael and Eric

Thank you for your reply. Yeah, you are right, the I found out my problem in my separator_ccc block, I did something stupid so that the two output streams become identical. Now I have solved the problem and now everything works perfectly.

Basically what I am trying to do is to separate two digital co-channel signals.

Thank you guys

Dawei

On 10/14/06, Michael Dickens <address@hidden> wrote:

Dawei - A first-order read-over of your code looks good to me; there
is nothing obviously incorrect - though of course this is just a code
snippet.  The overall code might have other issues.

On Oct 14, 2006, at 1:22 PM, Eric Blossom wrote:
> I'm not sure what you're trying to do with gr.separator_ccc.  If
> you're
> just trying to extract two different channels from the complex
> baseband signal from the usrp, gr.freq_xlating_fir works great.

Correct me if I'm wrong, Dawei, but I think this is the scenario:
there are 2 different transmitters and 1 receiver, all at the same
(center) frequency and bandwidth.  "separator_ccc" is meant to input
the single received signal (at baseband), and separate out the 2
transmissions into 2 streams ... kind of like using different CDMA
codes, but he's trying out a different algorithm (not CDMA).

>> However, my obeservation was that the two streams produce exactly
>> the same
>> packets (which are supposed to be produced only by A, not B, the
>> output of B
>> should be different). So could anyone help me check whether I am
>> doing
>> things correctly here?
>
> Have you logged the two outputs of gr.separator_ccc into files and
> examined them?  Are they by any chance identical?

I think that's what he's saying, that, yes, the 2 are identical.

I'm guessing that the question is whether or not 2 different GMSK2
demodulators can run at the same time - since they both use threads
to do their work and maybe those threads interact in unexpected
ways.  Or maybe some other issues.

There could also be other issues, but I think those would be with
this "separator_ccc" block or other programming that we can't see.  I
would guess he's trying to make sure everything else works before
going back to debugging that block.  I might be wrong ;) - MLD