# Boston, MA 02110-1301, USA.
#
-from gnuradio import gr
+from gnuradio import gr, optfir
class pfb_channelizer_ccf(gr.hier_block2):
'''
This simplifies the interface by allowing a single input stream to connect to this block.
It will then output a stream for each channel.
'''
- def __init__(self, numchans, taps, oversample_rate=1):
+ def __init__(self, numchans, taps=None, oversample_rate=1, atten=100):
gr.hier_block2.__init__(self, "pfb_channelizer_ccf",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(numchans, numchans, gr.sizeof_gr_complex)) # Output signature
self._numchans = numchans
- self._taps = taps
self._oversample_rate = oversample_rate
+ 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
+ made = False
+ while not made:
+ try:
+ self._taps = optfir.low_pass(1, self._numchans, 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))
+
self.s2ss = gr.stream_to_streams(gr.sizeof_gr_complex, self._numchans)
self.pfb = gr.pfb_channelizer_ccf(self._numchans, self._taps,
self._oversample_rate)
# Create a set of taps for the PFB channelizer
self._taps = gr.firdes.low_pass_2(1, self._fs, 475.50, 50,
- attenuation_dB=10, window=gr.firdes.WIN_BLACKMAN_hARRIS)
+ attenuation_dB=100, window=gr.firdes.WIN_BLACKMAN_hARRIS)
# Calculate the number of taps per channel for our own information
tpc = scipy.ceil(float(len(self._taps)) / float(self._M))