Hello Alex,
Few months ago, I was also having some similar issues, with respect
to GFSK modulation. I was using a M&M TED and I was getting a loss
percentage of about 7% mainly due to having a large amount of tx packets
(100 pkts/s) . So, it was suggested to me to use a correlator sync block to
pre sync the packets, and then do timing recovery.
But, since I also couldn't find a M-fsk or MSK modulation class I start
doing some research and I found that the timing recovery block works
perfectly if there are no noise in the demodulated output, so I created my
own version of demodulator which outputs values only of signal is present,
and in case of noise I just output some negative value, say like -5. It
just a concept if signal power is above a threshold then it is actual tx if
not it is a noise
I am not sure if this can solve your problem. Thought just in case you
may find it useful. Cheers.....!
Regards,
Mohamed Yaaseen
On Sun, 28 Jun 2020 at 02:43, Alex Roberts <arob...@gmail.com> wrote:
> Andy,
>
> I’m not sure how integrate the correlation sync block with gmsk. It
> expects modulated symbols and I’m not sure how to generate a modulated
> vector of gmsk symbols. There doesn’t seem to be a gmsk class that can be
> used by the modulate vector block.
>
> Thanks,
> Alex
>
> On Thursday, June 25, 2020, Andy Walls <a...@silverblocksystems.net>
> wrote:
>
>> Recommend reading
>>
>> https://www.gnuradio.org/grcon/grcon17/presentations/symbol_clock_recovery_and_improved_symbol_synchronization_blocks/Andy-Walls-Samples-to-Digital-Symbols.pdf
>>
>> Yeah, the MSK TED selections for the symbol sync block expect the
>> constant envelope FSK waveform on the input. Demodulation from FSK to
>> baseband pulses should happen after the symbol sync block.
>>
>
