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

[Josh Blum]

On 07/20/2011 12:24 PM, Yan Nie wrote:
> Dear all,
> 
> I am using USRP N200 +UHD with the LFRX daughter board to detect a
> 100kHz coded sinusoid wave then down convert the signal to baseband
> to see the coding method. The flow graph I am using is:
> 
> u2=uhd.single_usrp_source(device_addr="addr=192.168.10.2",io_type=uhd.io_type_t.COMPLEX_INT16,num_channels=1)
> decim_coeffs = gr.firdes.low_pass(1.0, 60e3,     #sampling frequency 
> 30e3,        #cutoff frequency .1e3, gr.firdes.WIN_BLACKMAN) 
> decim_filter = gr.fir_filter_fcc(1,decim_coeffs) 
> dst=gr.file_sink(gr.sizeof_gr_complex, filename) connect(u2,
> decim_filter,dst)
> 
> I am curious about how to configure the io_type_t for the receiver?
> COMPLEX_INT16 represents complex signed integer, 16-bit integer. I
> found only this io type could match the type provided for the input
> of fir_filter. Do I misunderstand something for this io type
> selection?
> 

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

-josh