PSK help

Hiya,

I have a heavily noise contaminated source (12db sig/noise)
which contains a BPSK signal.

I know the frequency, but obviously not the base phase or amplitude.

Does anyone know any algorithms/code to decode this, and get the
phase and ampltiude etc?

I have other semi stationary noise frequencies near the one in
question,
if that helps selection at all.

Any information, suggestions or even wild guesses warmly accepted.

I'm sure this question must come up quite a bit...
Thanks,
         M.

"Miso Soup Addict" <mick_from-dsp@yahoo.com> wrote in message
news:1103008071.496249.227520@f14g2000cwb.googlegroups.com...
> Hiya,
>
> I have a heavily noise contaminated source (12db sig/noise)
> which contains a BPSK signal.
>
> I know the frequency, but obviously not the base phase or amplitude.
>
> Does anyone know any algorithms/code to decode this, and get the
> phase and ampltiude etc?
>
> I have other semi stationary noise frequencies near the one in
> question,
> if that helps selection at all.
>
> Any information, suggestions or even wild guesses warmly accepted.
>
> I'm sure this question must come up quite a bit...
> Thanks,
>          M.
>
Hi! quite like Miso soup myself - not sure why though.

Yep , it comes up a lot , 12 dB SNR is not at all bad and you can just
matched filter , decimate and square to get a power estimate and phase
reference (assuming you know what your symbol rate and shaping is). As you
know what your frequency is you won't lose any signal power due to the
matched filtering and should be able to get a pretty good synchronisation.
You can then decide whether you would be better off without matched
filtering (e.g. if you don't have white noise at your receiver).

Best of Luck - Mike

"Miso Soup Addict" <mick_from-dsp@yahoo.com> wrote in message

> I have a heavily noise contaminated source (12db sig/noise)
> which contains a BPSK signal.
>
> I know the frequency, but obviously not the base phase or amplitude.
>
> Does anyone know any algorithms/code to decode this, and get the
> phase and ampltiude etc?

http://www.qsl.net/ae4jy/ao40rcv.htm

Kind Regards, Howard

On 13 Dec 2004 23:07:51 -0800, "Miso Soup Addict"
<mick_from-dsp@yahoo.com> wrote:

>Hiya,
>
>I have a heavily noise contaminated source (12db sig/noise)
>which contains a BPSK signal.
>
>I know the frequency, but obviously not the base phase or amplitude.
>
>Does anyone know any algorithms/code to decode this, and get the
>phase and ampltiude etc?
>
>I have other semi stationary noise frequencies near the one in
>question,
>if that helps selection at all.
>
>Any information, suggestions or even wild guesses warmly accepted.
>
>I'm sure this question must come up quite a bit...
>Thanks,
>         M.

For BPSK 12dB is actually a pretty high SNR.  Synchronization of
BPSK/QPSK at 0-3dB SNR is done pretty frequently, so 12dB shouldn't be
too bad.

As others have suggested, using typical synchronizing loops will do
the job, e.g., a Costas loop for the carrier and a traditional symbol
recovery loop for the timing.  There are quite a few texts out there
that have examples, so you might try browsing digital comm texts that
may be available to you.


Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org