Re: [Discuss-gnuradio] [EXT] Filter error

[Chesir, Aaron M.]

Sneha,

 

You did not present the configuration page of the UHD USRP block.

 

In any case, whenever a complaint refers to a frequency not being at or below half the sample rate, it means that the system thinks that you are attempting to either transmit or receive a signal at a frequency that is not below the Nyquist rate. The Nyquist rate is half the sampling frequency.

 

Huh?

 

It is a fundamental law in digital signal processing that to either transmit or receive a pure tone intact (i.e. not shifting to/from baseband), the sampling rate must meet or exceed twice the frequency of the signal.

 

• Aaron

 

From: Discuss-gnuradio <discuss-gnuradio-bounces+address@hidden> On Behalf Of Sneha vasan
Sent: Wednesday, June 5, 2019 10:34 AM
To: address@hidden
Subject: [EXT] [Discuss-gnuradio] Filter error

 

Hi everyone,

 

Can anybody guide me on this???.. I am using x310 with sampling rate of 1MHz.

 

Traceback (most recent call last):

  File "/home/sneha/My_waveform/past work/transmit.py", line 414, in <module>
    main()
  File "/home/sneha/My_waveform/past work/transmit.py", line 402, in main
    tb = top_block_cls()
  File "/home/sneha/My_waveform/past work/transmit.py", line 250, in __init__
    callback=lambda ok, payload: self.digital_ofdm_demod_0.recv_pkt(ok, payload),
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/digital/ofdm.py", line 223, in __init__
    options.log)
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/digital/ofdm_receiver.py", line 78, in __init__
    filter.firdes.WIN_HAMMING)   # filter type
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/filter/filter_swig.py", line 143, in low_pass
    return _filter_swig.firdes_low_pass(*args, **kwargs)

RuntimeError: firdes check failed: 0 < fa <= sampling_freq / 2

 

 

Regards,

Sneha