Re: [Discuss-gnuradio] samples/symbols CPFSK

[Olivier Goyette]

I'm aware of all this. This is why I asked because I don't understand why with 1 sps I can recover my entire message with no trouble but when it comes to a higher sps I can't. This afternoon I tried something with a MM clock recovery (with 6 sps). In simulation it gave me somewhat of a good result. I was able to recover my message but with some intermission (receiving 0's). When it came to real world, it wasn't working anymore. There is something unclear to me in this part.

Le 2016-07-21 18:48, "Marcus Müller" <address@hidden> a écrit :

any way you do this, if you're using quadrature demod, you must also not reduce the sample number until *after* you demodulated your FSK signal.

Again, for something to actually have a frequency, you'd need it to have a derivable phase. Derivation needs more than one sample.

Best regards,

Marcus

On 22.07.2016 00:42, Ed Criscuolo wrote:

Your flowgraph intrinsically has one symbol per sample in the data generation portion. You need a resampler just ahead of the throttle to interpolate in order to increase the number of samples per symbol. 

@(^.^)@ Ed

Sent from my iPhone

On Jul 21, 2016, at 3:15 PM, Olivier Goyette <address@hidden> wrote:

Hi all !

I've been working on this flowgraph for a while now and I've been able to pinpoint what is not working, but I don't understand how to resolve this so, that's why i'm asking for your guidance.

Take a look at the flowgraph i've joined. The thing that doesn't seem to be working on this setup is the samples/symbol in th CPFSK mod block.

When I set this parameter to 1 i'm able to retrieve my message at the file sink. So it tells me that what I did is okay in some way.

What is not working is when I set the same parameter to 6. At the beginning I wasn't using the rational resampler and it wasn't working. So I thought I would need something to "divide" the number of samples to retrieve each symbols. I tried it with the rational resampler block and set decimation to 6, but then, Daaaaaah......not working again.

There is something I can't work around here because I do not have sufficient knowledge about this samples/symbol thing.

I'd like to hear from you pals if you could give me a bit of information about how to make this work properly.

thank you !

<CPFSK.grc.png>

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