Re: [Discuss-gnuradio] Using WBFM block

[Tom Rondeau]

On Thu, Jun 5, 2014 at 4:37 AM, jason sam <address@hidden> wrote:

ok.Then how can i achieve FM for greater deviation.i.e. in MHz range in GRC?

What you're seeing is a result of the Remez algorithm in the optfir module not properly converging. Why isn't always clear; you can either tighten up or loosen the demands on the filter being built to try and fix it. You could also go into the code and replace the optfir call with firdes. The resulting filter might not be as good as you want and more taps, but it will at least always build.

Tom

 

On Thu, Jun 5, 2014 at 1:18 PM, Marcus Müller <address@hidden> wrote:

Given your question, I think you already know the answer. 2MHz is far from audio. Please refer to the wbfm example in GNU Radio, which has sane parameters.

Greetings,
Marcus

On 05.06.2014 09:58, jason sam wrote:

Hi All,
I am doing simple wide band FM..The flowgraph is as attached..When i
execute it i am getting following error:

gr_remez: insufficient extremals -- cannot continue
Traceback (most recent call last):
  File "/home/ali/Desktop/top_block.py", line 109, in <module>
    tb = top_block()
  File "/home/ali/Desktop/top_block.py", line 75, in __init__
    max_dev=4000000,
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/analog/wfm_tx.py",
line 69, in __init__
    40)              # stopband atten dB
  File "/usr/local/lib/python2.7/dist-packages/gnuradio/filter/optfir.py",
line 55, in low_pass
    taps = filter.pm_remez (n + nextra_taps, fo, ao, w, "bandpass")
  File
"/usr/local/lib/python2.7/dist-packages/gnuradio/filter/filter_swig.py",
line 466, in pm_remez
    return _filter_swig.pm_remez(*args, **kwargs)
RuntimeError: gr_remez: insufficient extremals -- cannot continue

Is the quadrature rate and audio rate are high?

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