diff options
| author | Andy Walls <awalls@md.metrocast.net> | 2016-03-30 09:15:45 -0400 |
|---|---|---|
| committer | Andy Walls <awalls@md.metrocast.net> | 2016-03-30 09:15:45 -0400 |
| commit | 515e40039e614ac86fb4c7be8dc4d067aa2bd9a3 (patch) | |
| tree | 0a9da028ca3ff74acdea28cb756fab363375b486 /gr-filter/examples | |
| parent | 2ae7809b845b7930c9b0120737167dd1251098eb (diff) | |
gr-analog: Add safety and default for FM preemphasis filter
The FM preemphasis filter design now precludes the user from
inducing a pole on the unit circle at z = -1.0 and z = 1.0.
A pole at either of these locations makes the filter unstable and
useless: feeding back "+/-inf" into an IIR filter has no good
recovery.
Also provide a reasonable, maximally safe default of 0.925*fs/2.0
for the high frequency corner, fh. This keeps the slope of the
preemphasis filter looking reasonable sane in the whole band; at
least for tau=75e-6 and fs=48000.
Diffstat (limited to 'gr-filter/examples')
| -rwxr-xr-x | gr-filter/examples/synth_to_chan.py | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/gr-filter/examples/synth_to_chan.py b/gr-filter/examples/synth_to_chan.py index 7a295eab47..88fb080a65 100755 --- a/gr-filter/examples/synth_to_chan.py +++ b/gr-filter/examples/synth_to_chan.py @@ -54,7 +54,7 @@ def main(): fmtx = list() for fi in freqs: s = analog.sig_source_f(fs, analog.GR_SIN_WAVE, fi, 1) - fm = analog.nbfm_tx(fs, 4*fs, max_dev=10000, tau=75e-6, fh=0.0) + fm = analog.nbfm_tx(fs, 4*fs, max_dev=10000, tau=75e-6, fh=0.925*(4*fs)/2.0) sigs.append(s) fmtx.append(fm) |