[Discuss-gnuradio] analysis_filterbank problem

[Sebastiaan Heunis]

Hi

I looked at usrp_flex_band.py to see how blks2.analysis_filterbank is
implemented.  The example runs on my PC.

I wrote a simple app where I want to decimate by 16 in the FPGA (no
HBF).  So I have samples coming in at 4Msps.  I then want to send this
stream to a 20 channel channeliser, resulting in output streams of
200ksps each.  I want to test this by connecting an FM demodulator and
see if I can channelise a part of the FM band.  Here is some of my
code.

self.u = usrp.source_c(decim_rate=16,fpga_filename="std_2rx_0tx.rbf")

if options.rx_subdev_spec is None:
        options.rx_subdev_spec = pick_subdevice(self.u)
                
self.subdev = usrp.selected_subdev(self.u,options.rx_subdev_spec)
self.u.set_mux(usrp.determine_rx_mux_value(self.u,options.rx_subdev_spec))
                
print "Using RX d'board %s" % (self.subdev.side_and_name(),)

self.set_freq(options.freq)

taps = []

f1 = open('fir_lowpass.txt','r')

for line in f1:
        tap = float(line)
        taps.append(tap)
f1.close()

#taps = optfir.low_pass(1,usrp_rate,70e3,100e3,0.1,60)

pfb = blks2.analysis_filterbank(20,taps)

self.connect(self.u,pfb)

The application works until I try to connect the usrp source to the
filterbank.  I get a Segmentation fault when I try to do this.  Does
anyone know what might be wrong?

Thanks in advance.

Sebastiaan

-- 
Sebastiaan Heunis
Radar and Remote Sensing Group, University of Cape Town
Tel:  +27 83 305 5667