We just realized that blks2.standard_squelch does not work since
GnuRadio
3.1.2. I installed 3.1.1 from source and it works fine, 3.1.2 and 3.1.3
it
doesn’t (basically everything passes through, independently of the
threshold). We are using the usrp_nbfm_ptt.py (unchanged) from the
gnuradio-examples. Anyone else notice this, or is it just our systems?
By the way, reading the code of standard_squelch.py, it seems to me that
since
self.gate = gr.threshold_ff(0.3,0.43,0)
and
def set_threshold(self, threshold):
self.gate.set_hi(threshold)
squelch_range() should return (0.3, 1.0, 1.0/100), not (0.0, 1.0,
1.0/100).
Am I wrong?
I did some more research (although I’m unsure about my ability to
resolve
this on my own). Here’s what I’ve found so far:
- the functioning of the standard_squelch depends on the audio_rate you
set.
For the default 32kS/s it doesn’t work, everything passes through, and
changing the threshold value does not seem to change anything.
- if you lower the audio rate, squelch does seem to work, though the
output
is rather noisy
- looking at the underlying code, i notice that gr_threshold_ff.cc (used
by
standard squelch) outputs
if (in[i] > d_hi) {
out[i] = 1.0;
while gr_simple_squelch_cc.cc outputs
if (f >= d_threshold)
out[i] = in[i];
I’m not sure if this is making the difference…
Can someone test and tell me if squelch works in the example
usrp/usrp_nbfm_ptt.py for them? Jonathan?
Thank you in advance for your help
Dimitris S.
“If you think you’re too small to make a difference, try sleeping with a
mosquito!” - Amnesty International