From 6e8f5922b826213c976cd36c7411fd315ef7f456 Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Thu, 6 Oct 2011 12:01:46 -0400
Subject: Added FFF version of pfb_arb_resampler to Python hier block (where
only the rate is required).
---
.../python/gnuradio/blks2impl/pfb_arb_resampler.py | 53 ++++++++++++++++++++++
1 file changed, 53 insertions(+)
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/pfb_arb_resampler.py b/gnuradio-core/src/python/gnuradio/blks2impl/pfb_arb_resampler.py
index 62f40582e6..3aadf700b6 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/pfb_arb_resampler.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/pfb_arb_resampler.py
@@ -73,3 +73,56 @@ class pfb_arb_resampler_ccf(gr.hier_block2):
def set_rate(self, rate):
self.pfb.set_rate(rate)
+
+
+class pfb_arb_resampler_fff(gr.hier_block2):
+ '''
+ Convenience wrapper for the polyphase filterbank arbitrary resampler.
+
+ The block takes a single float stream in and outputs a single float
+ stream out. As such, it requires no extra glue to handle the input/output
+ streams. This block is provided to be consistent with the interface to the
+ other PFB block.
+ '''
+ def __init__(self, rate, taps=None, flt_size=32, atten=100):
+ gr.hier_block2.__init__(self, "pfb_arb_resampler_fff",
+ gr.io_signature(1, 1, gr.sizeof_float), # Input signature
+ gr.io_signature(1, 1, gr.sizeof_float)) # Output signature
+
+ self._rate = rate
+ self._size = flt_size
+
+ if taps is not None:
+ self._taps = taps
+ else:
+ # Create a filter that covers the full bandwidth of the input signal
+ bw = 0.4
+ tb = 0.2
+ ripple = 0.1
+ #self._taps = gr.firdes.low_pass_2(self._size, self._size, bw, tb, atten)
+ made = False
+ while not made:
+ try:
+ self._taps = optfir.low_pass(self._size, self._size, bw, bw+tb, ripple, atten)
+ made = True
+ except RuntimeError:
+ ripple += 0.01
+ made = False
+ print("Warning: set ripple to %.4f dB. If this is a problem, adjust the attenuation or create your own filter taps." % (ripple))
+
+ # Build in an exit strategy; if we've come this far, it ain't working.
+ if(ripple >= 1.0):
+ raise RuntimeError("optfir could not generate an appropriate filter.")
+
+ self.pfb = gr.pfb_arb_resampler_fff(self._rate, self._taps, self._size)
+ #print "PFB has %d taps\n" % (len(self._taps),)
+
+ self.connect(self, self.pfb)
+ self.connect(self.pfb, self)
+
+ # Note -- set_taps not implemented in base class yet
+ def set_taps(self, taps):
+ self.pfb.set_taps(taps)
+
+ def set_rate(self, rate):
+ self.pfb.set_rate(rate)
--
cgit v1.2.3
From 408868b41f0c81168199a531aab4db426f9e5d23 Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Thu, 6 Oct 2011 13:47:24 -0400
Subject: Formatting and normalizing freq limits.
---
.../src/python/gnuradio/blks2impl/wfm_rcv_fmdet.py | 136 ++++++++++++---------
1 file changed, 81 insertions(+), 55 deletions(-)
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv_fmdet.py b/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv_fmdet.py
index 858b9cde6a..3a93a11d64 100755
--- a/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv_fmdet.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv_fmdet.py
@@ -28,8 +28,9 @@ class wfm_rcv_fmdet(gr.hier_block2):
"""
Hierarchical block for demodulating a broadcast FM signal.
- The input is the downconverted complex baseband signal (gr_complex).
- The output is two streams of the demodulated audio (float) 0=Left, 1=Right.
+ The input is the downconverted complex baseband signal
+ (gr_complex). The output is two streams of the demodulated
+ audio (float) 0=Left, 1=Right.
@param demod_rate: input sample rate of complex baseband input.
@type demod_rate: float
@@ -39,16 +40,15 @@ class wfm_rcv_fmdet(gr.hier_block2):
gr.hier_block2.__init__(self, "wfm_rcv_fmdet",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(2, 2, gr.sizeof_float)) # Output signature
- lowfreq = -125e3
- highfreq = 125e3
+ lowfreq = -125e3/demod_rate
+ highfreq = 125e3/demod_rate
audio_rate = demod_rate / audio_decimation
-
- # We assign to self so that outsiders can grab the demodulator
+ # We assign to self so that outsiders can grab the demodulator
# if they need to. E.g., to plot its output.
#
# input: complex; output: float
-
+
self.fm_demod = gr.fmdet_cf (demod_rate, lowfreq, highfreq, 0.05)
# input: float; output: float
@@ -62,25 +62,31 @@ class wfm_rcv_fmdet(gr.hier_block2):
15000 ,
width_of_transition_band,
gr.firdes.WIN_HAMMING)
+
# input: float; output: float
self.audio_filter = gr.fir_filter_fff (audio_decimation, audio_coeffs)
if 1:
- # Pick off the stereo carrier/2 with this filter. It attenuated 10 dB so apply 10 dB gain
- # We pick off the negative frequency half because we want to base band by it!
- ## NOTE THIS WAS HACKED TO OFFSET INSERTION LOSS DUE TO DEEMPHASIS
+ # Pick off the stereo carrier/2 with this filter. It
+ # attenuated 10 dB so apply 10 dB gain We pick off the
+ # negative frequency half because we want to base band by
+ # it!
+ ## NOTE THIS WAS HACKED TO OFFSET INSERTION LOSS DUE TO
+ ## DEEMPHASIS
stereo_carrier_filter_coeffs = gr.firdes.complex_band_pass(10.0,
- demod_rate,
- -19020,
- -18980,
- width_of_transition_band,
- gr.firdes.WIN_HAMMING)
+ demod_rate,
+ -19020,
+ -18980,
+ width_of_transition_band,
+ gr.firdes.WIN_HAMMING)
#print "len stereo carrier filter = ",len(stereo_carrier_filter_coeffs)
#print "stereo carrier filter ", stereo_carrier_filter_coeffs
#print "width of transition band = ",width_of_transition_band, " audio rate = ", audio_rate
- # Pick off the double side band suppressed carrier Left-Right audio. It is attenuated 10 dB so apply 10 dB gain
+ # Pick off the double side band suppressed carrier
+ # Left-Right audio. It is attenuated 10 dB so apply 10 dB
+ # gain
stereo_dsbsc_filter_coeffs = gr.firdes.complex_band_pass(20.0,
demod_rate,
@@ -90,101 +96,121 @@ class wfm_rcv_fmdet(gr.hier_block2):
gr.firdes.WIN_HAMMING)
#print "len stereo dsbsc filter = ",len(stereo_dsbsc_filter_coeffs)
#print "stereo dsbsc filter ", stereo_dsbsc_filter_coeffs
- # construct overlap add filter system from coefficients for stereo carrier
- self.stereo_carrier_filter = gr.fir_filter_fcc(audio_decimation, stereo_carrier_filter_coeffs)
-
- # carrier is twice the picked off carrier so arrange to do a commplex multiply
+ # construct overlap add filter system from coefficients
+ # for stereo carrier
+ self.stereo_carrier_filter = gr.fir_filter_fcc(audio_decimation,
+ stereo_carrier_filter_coeffs)
+ # carrier is twice the picked off carrier so arrange to do
+ # a commplex multiply
self.stereo_carrier_generator = gr.multiply_cc();
# Pick off the rds signal
-
stereo_rds_filter_coeffs = gr.firdes.complex_band_pass(30.0,
- demod_rate,
- 57000 - 1500,
- 57000 + 1500,
- width_of_transition_band,
- gr.firdes.WIN_HAMMING)
+ demod_rate,
+ 57000 - 1500,
+ 57000 + 1500,
+ width_of_transition_band,
+ gr.firdes.WIN_HAMMING)
#print "len stereo dsbsc filter = ",len(stereo_dsbsc_filter_coeffs)
#print "stereo dsbsc filter ", stereo_dsbsc_filter_coeffs
# construct overlap add filter system from coefficients for stereo carrier
- self.rds_signal_filter = gr.fir_filter_fcc(audio_decimation, stereo_rds_filter_coeffs)
-
-
-
-
-
-
+ self.rds_signal_filter = gr.fir_filter_fcc(audio_decimation,
+ stereo_rds_filter_coeffs)
self.rds_carrier_generator = gr.multiply_cc();
self.rds_signal_generator = gr.multiply_cc();
self_rds_signal_processor = gr.null_sink(gr.sizeof_gr_complex);
-
-
alpha = 5 * 0.25 * math.pi / (audio_rate)
beta = alpha * alpha / 4.0
max_freq = -2.0*math.pi*18990/audio_rate;
- min_freq = -2.0*math.pi*19010/audio_rate;
+ min_freq = -2.0*math.pi*19010/audio_rate;
+ self.stereo_carrier_pll_recovery = gr.pll_refout_cc(alpha,beta,
+ max_freq,
+ min_freq);
+
+ #self.stereo_carrier_pll_recovery.squelch_enable(False)
+ ##pll_refout does not have squelch yet, so disabled for
+ #now
- self.stereo_carrier_pll_recovery = gr.pll_refout_cc(alpha,beta,max_freq,min_freq);
- #self.stereo_carrier_pll_recovery.squelch_enable(False) #pll_refout does not have squelch yet, so disabled for now
-
-
- # set up mixer (multiplier) to get the L-R signal at baseband
+ # set up mixer (multiplier) to get the L-R signal at
+ # baseband
self.stereo_basebander = gr.multiply_cc();
- # pick off the real component of the basebanded L-R signal. The imaginary SHOULD be zero
+ # pick off the real component of the basebanded L-R
+ # signal. The imaginary SHOULD be zero
self.LmR_real = gr.complex_to_real();
self.Make_Left = gr.add_ff();
self.Make_Right = gr.sub_ff();
- self.stereo_dsbsc_filter = gr.fir_filter_fcc(audio_decimation, stereo_dsbsc_filter_coeffs)
+ self.stereo_dsbsc_filter = gr.fir_filter_fcc(audio_decimation,
+ stereo_dsbsc_filter_coeffs)
if 1:
- # send the real signal to complex filter to pick off the carrier and then to one side of a multiplier
- self.connect (self, self.fm_demod,self.stereo_carrier_filter,self.stereo_carrier_pll_recovery, (self.stereo_carrier_generator,0))
+ # send the real signal to complex filter to pick off the
+ # carrier and then to one side of a multiplier
+ self.connect (self, self.fm_demod, self.stereo_carrier_filter,
+ self.stereo_carrier_pll_recovery,
+ (self.stereo_carrier_generator,0))
+
# send the already filtered carrier to the otherside of the carrier
+ # the resulting signal from this multiplier is the carrier
+ # with correct phase but at -38000 Hz.
self.connect (self.stereo_carrier_pll_recovery, (self.stereo_carrier_generator,1))
- # the resulting signal from this multiplier is the carrier with correct phase but at -38000 Hz.
# send the new carrier to one side of the mixer (multiplier)
self.connect (self.stereo_carrier_generator, (self.stereo_basebander,0))
+
# send the demphasized audio to the DSBSC pick off filter, the complex
# DSBSC signal at +38000 Hz is sent to the other side of the mixer/multiplier
- self.connect (self.fm_demod,self.stereo_dsbsc_filter, (self.stereo_basebander,1))
# the result is BASEBANDED DSBSC with phase zero!
+ self.connect (self.fm_demod,self.stereo_dsbsc_filter, (self.stereo_basebander,1))
- # Pick off the real part since the imaginary is theoretically zero and then to one side of a summer
+ # Pick off the real part since the imaginary is
+ # theoretically zero and then to one side of a summer
self.connect (self.stereo_basebander, self.LmR_real, (self.Make_Left,0))
- #take the same real part of the DSBSC baseband signal and send it to negative side of a subtracter
+
+ #take the same real part of the DSBSC baseband signal and
+ #send it to negative side of a subtracter
self.connect (self.LmR_real,(self.Make_Right,1))
- # Make rds carrier by taking the squared pilot tone and multiplying by pilot tone
+ # Make rds carrier by taking the squared pilot tone and
+ # multiplying by pilot tone
self.connect (self.stereo_basebander,(self.rds_carrier_generator,0))
self.connect (self.stereo_carrier_pll_recovery,(self.rds_carrier_generator,1))
- # take signal, filter off rds, send into mixer 0 channel
+
+ # take signal, filter off rds, send into mixer 0 channel
self.connect (self.fm_demod,self.rds_signal_filter,(self.rds_signal_generator,0))
- # take rds_carrier_generator output and send into mixer 1 channel
+
+ # take rds_carrier_generator output and send into mixer 1
+ # channel
self.connect (self.rds_carrier_generator,(self.rds_signal_generator,1))
- # send basebanded rds signal and send into "processor" which for now is a null sink
+
+ # send basebanded rds signal and send into "processor"
+ # which for now is a null sink
self.connect (self.rds_signal_generator,self_rds_signal_processor)
if 1:
- # pick off the audio, L+R that is what we used to have and send it to the summer
+ # pick off the audio, L+R that is what we used to have and
+ # send it to the summer
self.connect(self.fm_demod, self.audio_filter, (self.Make_Left, 1))
- # take the picked off L+R audio and send it to the PLUS side of the subtractor
+
+ # take the picked off L+R audio and send it to the PLUS
+ # side of the subtractor
self.connect(self.audio_filter,(self.Make_Right, 0))
+
# The result of Make_Left gets (L+R) + (L-R) and results in 2*L
# The result of Make_Right gets (L+R) - (L-R) and results in 2*R
self.connect(self.Make_Left , self.deemph_Left, (self, 0))
self.connect(self.Make_Right, self.deemph_Right, (self, 1))
+
# NOTE: mono support will require variable number of outputs in hier_block2s
# See ticket:174 in Trac database
#else:
--
cgit v1.2.3