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[Discuss-gnuradio] pll refout vs carriertracking
From: |
Charles Swiger |
Subject: |
[Discuss-gnuradio] pll refout vs carriertracking |
Date: |
Mon, 10 Jul 2006 15:27:25 -0400 |
All - Do I understand correctly that gr.pll_carriertracking_cc() is
supposed to downconvert to DC? I don't see it doing that, and can't
see in the work functions where that magic would be accomplished.
Just want to make sure I'm building the most efficient graph possible.
I tried both in an existing AM detector with a 7.5KHz IF and both work
just the same with an external mixer.
----------------------------------------------------------------
refout:
int
gr_pll_refout_cc::work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const gr_complex *iptr = (gr_complex *) input_items[0];
gr_complex *optr = (gr_complex *) output_items[0];
float error;
float t_imag, t_real;
int size = noutput_items;
while (size-- > 0) {
error = phase_detector(*iptr++,d_phase);
d_freq = d_freq + d_beta * error;
d_phase = mod_2pi(d_phase + d_freq + d_alpha * error);
if (d_freq > d_max_freq)
d_freq = d_max_freq;
else if (d_freq < d_min_freq)
d_freq = d_min_freq;
gr_sincosf(d_phase,&t_imag,&t_real);
*optr++ = gr_complex(t_real,t_imag);
}
return noutput_items;
}
-----------------------------------------------------------------
carriertracking:
int
gr_pll_carriertracking_cc::work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const gr_complex *iptr = (gr_complex *) input_items[0];
gr_complex *optr = (gr_complex *) output_items[0];
float error;
float t_imag, t_real;
for (int i = 0; i < noutput_items; i++){
error = phase_detector(iptr[i],d_phase);
d_freq = d_freq + d_beta * error;
d_phase = mod_2pi(d_phase + d_freq + d_alpha * error);
if (d_freq > d_max_freq)
d_freq = d_max_freq;
else if (d_freq < d_min_freq)
d_freq = d_min_freq;
gr_sincosf(d_phase,&t_imag,&t_real);
optr[i] = gr_complex(t_real,t_imag);
d_locksig = d_locksig * (1.0 - d_alpha) + d_alpha*(iptr[i].real() *
t_real + iptr[i].imag() * t_imag);
if ((d_squelch_enable) && !lock_detector())
optr[i] = 0;
}
return noutput_items;
}
- [Discuss-gnuradio] pll refout vs carriertracking,
Charles Swiger <=