Re: [Discuss-gnuradio] UHD example

[Elvis Dowson]

Hi Josh,

On Jul 16, 2010, at 9:09 PM, Josh Blum wrote:

> This is a bug in the wbx reference divider code. It will be fixed soon. What 
> frequency were you requesting?

I was entering 1e6 (1000000 Hz), which was an incorrect value I guess, since 
the WBX cannot receive 1 MHz, which resulted in the following error:

terminate called after throwing an instance of 'std::invalid_argument'
  what():  key not found in dict

I tried with 2e9 (2GHz), and since that was within a valid input range, now it 
gives me the following error:

>>> gr_fir_fff: using SSE
Current recv sock buff size: 50000000 bytes
Current send sock buff size: 50000000 bytes
Using: WBX TX (0x0053)
Using: WBX RX (0x0052)
RX samples per packet: 362
TX samples per packet: 363
Recv pirate num frames: 33967
gr_block_executor: source <gr_block uhd simple source (7)> produced no output.  
We're marking it DONE.

I have attached the GRC file :

usrp2_wfm_rcv.grc
Description: Binary data

Do you have a working GRC example of WFM demodulation? I'm having difficultly 
trying to covert the existing python script to GRC, since the libraries are 
unfamiliar to me at the moment. 

e.g. I don't know which GRC blocks correspond to the following code fragments:

        # channel filter co-efficients
        chan_filt_coeffs = optfir.low_pass (1,           # gain
                                            usrp_rate,   # sampling rate
                                            80e3,        # passband cutoff
                                            115e3,       # stopband cutoff
                                            0.1,         # passband ripple
                                            60)          # stopband attenuation


        chan_filt = gr.fir_filter_ccf (chanfilt_decim, chan_filt_coeffs)


Best regards,

Elvis Dowson