Re: Clock synchronization problem of modulated signal: How to set the parameters to make the synchronization effect better?

[Daniel Estévez]

El 3/6/21 a las 12:12, Marcus M??ller escribi??:

> > then use "polyphase arbitrary resampler" for pulse shaping,
>
> Unusual choice! You'd almost always want to use an interpolating FIR filter for 
> this.

Hi Marcus,

AFAIK the polyphase arbitrary resampler is a good choice when there is 
not a simple n:m interpolation relationship between the symbol rate and 
sample rate. I think this block implements what fred harris describes in 
Section 7.5 of his book. In the end it is some kind of interpolating FIR 
filter. You need to define your prototype filter correctly according to 
your pulse shape, though.

I've used it successfully for the transmitter of a 32APSK modem:

https://destevez.net/2021/05/32apsk-narrowband-modem-for-qo-100/

Best,

Daniel.

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