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Re: [Discuss-gnuradio] analysis_filterbank problem
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] analysis_filterbank problem |
Date: |
Wed, 7 Jan 2009 10:44:09 -0800 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Wed, Jan 07, 2009 at 01:53:03PM +0200, Sebastiaan Heunis wrote:
> 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
Run gdb to find out where the segfault is occurring.
http://www.gnu.org/software/gnuradio/doc/howto-write-a-block.html#debugging
Are you sure you want the half-band disabled?
You can run decim=16 with it on. The pass band will be flatter.
Eric