Re: [Discuss-gnuradio] pll_refout_cc - finding optimum alpha & beta ??

[Robert McGwier]

Matt Ettus wrote:
> > It just seeemd strange to me that a very large number, d_freq, which is
> > bounds limited to between d_min_freq and d_max_freq, is inside a
> > function trying to limit it's output to between +PI and -PI.
> >
> > if(100e3 > M_PI)
> >   return(100e3-M_TWOPI) 
> >
> > or 99993.7168...   error can get close to zero, but frequency will
> > never be less than d_freq_min.
> >
> >     
>
>
> d_freq is not in Hz.  It needs to be in radians per sample, which should
> always be less than PI.
>
> Matt
>
>   
It is irrelevant to the oscillator if the phase angle is between 0 and 
2pi or -pi, pi since the transcendental functions will handle either.  
Having it from -pi, pi is correct in this case because our phase error 
will be from -pi to pi,  or frequency per sample will be from -pi,pi.  
The original function is correct.

Bob




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