Re: [Discuss-gnuradio] RE: [Commit-gnuradio] gnuradio-core/src/lib/general gr_correlate_acce...

[Matt Ettus]

Johnathan Corgan wrote:

> Matt Ettus wrote:
>
>  
>
> > On the other hand, since it is differential, you usually don't use a
> > costas loop with pi/4-DQPSK.
> >    
>
> Is there a different way to assure frequency/phase lock, or are they not
> needed?  I know for differential detection constellation doesn't need to
> be locked in the correct absolute phase, but is it the case it can be
> left to rotate as well?
>  
There is no need for phase lock.  Normally what you would do is estimate 
the frequency error, multiply it by symbol period, and subtract that 
phase from the delta phase.

Matt