Re: [Discuss-gnuradio] io_type configuration for uhd.single_usrp_source

[Nick Foster]

On Thu, 2011-07-21 at 11:28 -0400, Yan Nie wrote:
> > well, sizeof(complex<short>) == sizeof(float), which means gnuradio will
> > let you connect those blocks, but that definitively wont work.
> > 
> > For the UHD source, use COMPLEX_FLOAT32. For the FIR filter, use complex
> > input.
> > 
> > gnuradio-companion might help you a lot:
> > http://en.wikipedia.org/wiki/GNU_Radio_Companion
> 
> I appreciate your reply. I changed the io type for UHD source and type of the 
> input for FIR filter, and got them matched, which leads the final result to 
> the right direction, but still not quite right. It is just a simple trial to 
> detect a 100kHz sinusoid signal and down convert the frequency to 1kHz. I am 
> expecting a 1kHz sinusoid wave from plotting, but it only gave some irregular 
> oscillation at the beginning. I am still confused that what could be the 
> problem here?
> 
> u2=uhd.single_usrp_source(device_addr="addr=192.168.10.2",io_type=uhd.io_type_t.COMPLEX_FLOAT32,num_channels=1)
> u2.set_samp_rate(250e3)
> treq = uhd.tune_request(freq)
> tr = u2.set_center_freq(self.treq)
> decim_coeffs = gr.firdes.low_pass(1.0,
>                               5e3,     #sampling frequency
>                               2e3,        #cutoff frequency
>                               .1e3,
>                               gr.firdes.WIN_BLACKMAN)
> decim_filter = gr.fir_filter_ccf(1,decim_coeffs)
> dst = gr.file_sink(gr.sizeof_gr_complex,filename)
> connect(self._u2, self.decim_filter,self.dst)

Yan,

Why is your filter sampling frequency 5kHz, when your USRP sample rate
is 250kHz?

--n

> 
> 
> Thank you so much for your help
> 
> with thanks,
> Yan
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio