Re: [Discuss-gnuradio] pll refout vs carriertracking
Moin, Am Thu, 13 Jul 2006 13:44:50 -0400 schrieb Robert McGwier: > Sorry. I missed what you referred to in the early email. I misread > it. I agree that refout and carriertracking should not be doing the > same thing. I will look at it. In the meantime the docs have been updated so that carriertracking is described to be mixing the input with the recovered carrier. Yet, the code is still unchanged (e.g. carriertracking and refout still do exactly the same). This took me several hours to figure out. Attached is a trivial patch to fix that. -- Henryk Plötz Grüße aus Berlin ~~~ Un-CDs, nein danke! http://www.heise.de/ct/cd-register/ ~~~ ~ Help Microsoft fight software piracy: Give Linux to a friend today! ~ Index: gnuradio-core/src/lib/general/gr_pll_carriertracking_cc.cc === --- gnuradio-core/src/lib/general/gr_pll_carriertracking_cc.cc (Revision 3290) +++ gnuradio-core/src/lib/general/gr_pll_carriertracking_cc.cc (Arbeitskopie) @@ -107,7 +107,7 @@ 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); +optr[i] = iptr[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()) pgpx1QSZXhw6N.pgp Description: PGP signature ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] pll refout vs carriertracking
Sorry. I missed what you referred to in the early email. I misread it. I agree that refout and carriertracking should not be doing the same thing. I will look at it. Bob Matt Ettus wrote: Robert McGwier wrote: I did that on purpose. There are myriad instances where you want the recovered carrier or tone but not have the complex input mixed to the "new zero". If you want a recovery and baseband, I suggest that rather than do an if test, we make a new module that is track and mix. Yes, but that is what refout is for. Right now refout and carriertracking do the exact same thing. Matt -- AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman "An expert is a man who has made all the mistakes which can be made in a very narrow field." Niels Bohr ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] pll refout vs carriertracking
Robert McGwier wrote: I did that on purpose. There are myriad instances where you want the recovered carrier or tone but not have the complex input mixed to the "new zero". If you want a recovery and baseband, I suggest that rather than do an if test, we make a new module that is track and mix. Yes, but that is what refout is for. Right now refout and carriertracking do the exact same thing. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] pll refout vs carriertracking
I did that on purpose. There are myriad instances where you want the recovered carrier or tone but not have the complex input mixed to the "new zero". If you want a recovery and baseband, I suggest that rather than do an if test, we make a new module that is track and mix. Bob Matt Ettus wrote: Bob -- I think we have a problem with carriertracking -- it was supposed to mix the input signal down, and output that, but it looks like it just outputs the reference, like refout. Charles -- To detect AM, you can: 1 - take output of pll_refout_cc, take its complex conjugate and complex multiply that by the input signal. The audio you want is in the real output. The imaginary output should only have noise. If the RMS value of both is about the same you don't have lock, or the signal is very noisy. -OR- 2 - Fix pll_carriertracking_cc to do what I said in 1, above, since that is what it was supposed to do. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] pll refout vs carriertracking
Bob --
I think we have a problem with carriertracking -- it was supposed to mix
the input signal down, and output that, but it looks like it just
outputs the reference, like refout.
Charles --
To detect AM, you can:
1 - take output of pll_refout_cc, take its complex conjugate and complex
multiply that by the input signal. The audio you want is in the real
output. The imaginary output should only have noise. If the RMS value
of both is about the same you don't have lock, or the signal is very noisy.
-OR-
2 - Fix pll_carriertracking_cc to do what I said in 1, above, since that
is what it was supposed to do.
Matt
Robert McGwier wrote:
You are correct. pll_carriertracking_cc returns the recovered
carrier. Sending to baseband is then done by a complex multiply
block, don't forget the conjugation.
Bob
Charles Swiger wrote:
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;
}
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Re: [Discuss-gnuradio] pll refout vs carriertracking
You are correct. pll_carriertracking_cc returns the recovered carrier.
Sending to baseband is then done by a complex multiply block, don't
forget the conjugation.
Bob
Charles Swiger wrote:
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;
}
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--
AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,
NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman
"An expert is a man who has made all the mistakes which can be
made in a very narrow field." Niels Bohr
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[Discuss-gnuradio] pll refout vs carriertracking
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;
}
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