diff options
| author | efardin <efardin@ieee.org> | 2020-12-22 22:19:37 +1100 |
|---|---|---|
| committer | Martin Braun <martin@gnuradio.org> | 2021-01-15 23:40:38 +0100 |
| commit | a66ee6c92c5a0b781f2e680f3def1471bebf2339 (patch) | |
| tree | d2e013231ceb372f92c06b4432ea629ad3385d21 /gr-analog | |
| parent | c199a8afdd024246e83982f54d08b18bf220d225 (diff) | |
analog: fm: Add audio_rate variable and deemph_tau parameters
Signed-off-by: efardin <efardin@ieee.org>
Diffstat (limited to 'gr-analog')
| -rw-r--r-- | gr-analog/grc/analog_wfm_rcv_pll.block.yml | 6 | ||||
| -rw-r--r-- | gr-analog/python/analog/wfm_rcv_pll.py | 9 |
2 files changed, 11 insertions, 4 deletions
diff --git a/gr-analog/grc/analog_wfm_rcv_pll.block.yml b/gr-analog/grc/analog_wfm_rcv_pll.block.yml index 4364ce8c70..5fa98acd6d 100644 --- a/gr-analog/grc/analog_wfm_rcv_pll.block.yml +++ b/gr-analog/grc/analog_wfm_rcv_pll.block.yml @@ -9,6 +9,10 @@ parameters: - id: audio_decimation label: Audio Decimation dtype: int +- id: deemph_tau + label: Deemphasis Tau + dtype: real + default: 75e-6 inputs: - domain: stream @@ -24,7 +28,7 @@ outputs: templates: imports: from gnuradio import analog - make: "analog.wfm_rcv_pll(\n\tdemod_rate=${quad_rate},\n\taudio_decimation=${audio_decimation},\n\ + make: "analog.wfm_rcv_pll(\n\tdemod_rate=${quad_rate},\n\taudio_decimation=${audio_decimation},\n\tdeemph_tau=${deemph_tau},\n\ )" file_format: 1 diff --git a/gr-analog/python/analog/wfm_rcv_pll.py b/gr-analog/python/analog/wfm_rcv_pll.py index 7f38c05b32..67d7384e45 100644 --- a/gr-analog/python/analog/wfm_rcv_pll.py +++ b/gr-analog/python/analog/wfm_rcv_pll.py @@ -17,7 +17,7 @@ from gnuradio.filter import firdes from gnuradio import analog class wfm_rcv_pll(gr.hier_block2): - def __init__(self, demod_rate, audio_decimation): + def __init__(self, demod_rate, audio_decimation, deemph_tau): """ Hierarchical block for demodulating a broadcast FM signal. @@ -27,6 +27,7 @@ class wfm_rcv_pll(gr.hier_block2): Args: demod_rate: input sample rate of complex baseband input. (float) audio_decimation: how much to decimate demod_rate to get to audio. (integer) + deemph_tau: deemphasis ime constant in seconds (75us in US, 50us in EUR). (float) """ gr.hier_block2.__init__(self, "wfm_rcv_pll", gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature @@ -40,11 +41,13 @@ class wfm_rcv_pll(gr.hier_block2): # Variables ################################################## self.demod_rate = demod_rate + self.deemph_tau = deemph_tau self.stereo_carrier_filter_coeffs_0 = stereo_carrier_filter_coeffs_0 = firdes.band_pass(-2.0, demod_rate, 37600, 38400, 400, fft.window.WIN_HAMMING, 6.76) self.stereo_carrier_filter_coeffs = stereo_carrier_filter_coeffs = firdes.complex_band_pass(1.0, demod_rate, 18980, 19020, 1500, fft.window.WIN_HAMMING, 6.76) self.deviation = deviation = 75000 self.audio_filter = audio_filter = firdes.low_pass(1, demod_rate, 15000,1500, fft.window.WIN_HAMMING, 6.76) self.audio_decim = audio_decim = audio_decimation + self.audio_rate = audio_rate = demod_rate / audio_decim self.samp_delay = samp_delay = (len(stereo_carrier_filter_coeffs) - 1) // 2 + (len(stereo_carrier_filter_coeffs_0) - 1) // 2 ################################################## @@ -65,8 +68,8 @@ class wfm_rcv_pll(gr.hier_block2): self.blocks_add_xx_0 = blocks.add_vff(1) self.analog_quadrature_demod_cf_0 = analog.quadrature_demod_cf(demod_rate/(2*math.pi*deviation)) self.analog_pll_refout_cc_0 = analog.pll_refout_cc(0.001, 2*math.pi * 19200 / demod_rate, 2*math.pi * 18800 / demod_rate) - self.analog_fm_deemph_0_0 = analog.fm_deemph(fs=demod_rate//audio_decim, tau=75e-6) - self.analog_fm_deemph_0 = analog.fm_deemph(fs=demod_rate//audio_decim, tau=75e-6) + self.analog_fm_deemph_0_0 = analog.fm_deemph(fs=audio_rate, tau=deemph_tau) + self.analog_fm_deemph_0 = analog.fm_deemph(fs=audio_rate, tau=deemph_tau) self.blocks_delay_0 = blocks.delay(gr.sizeof_float*1, samp_delay) ################################################## |