Re: [Discuss-gnuradio] Specify taps for 'FFT_Filter' using function call to 'GLFSR Source'

[Cinaed Simson]

On 09/27/2017 12:07 AM, Marcus Müller wrote:
> Hi Cinaed,
> 
> interestingly, period() gives me 0b(degree ones) all the time, so I'm
> not sure we don't see a bug there.

I looped over degree in range(1,33)

  src=digital.glfsr_source_f(degree,True,mask,seed)
  src=digital.glfsr_source_b(degree,True,mask,seed)

and I consistently get a period of degree**2-1 both float and byte types.

But I did notice running the GLFSR source in a flow graph with type Byte
generates an asymmetric frequency spectrum about the center frequency.

There are persistent dips in the amplitude at roughly -1.27 Hz and -2.58
Hz which aren't present in the positive frequencies - and are not
present in the spectrum for type Float.

-- Cinaed


> 
> Best regards,
> 
> Marcus
> 
> 
> On 09/27/2017 12:01 AM, Cinaed Simson wrote:
>> Try
>>
>>   from gnuradio import digital as digital
>>   src=digital.glfsr_source_f(13,False,0x0000100D,0xA5A5)
>>   src.period()
>>
>> src has type <gr_block glfsr_source_f (0)>
>>
>> Unfortunately, I don't know enough to be able to convert to an array of
>> floats need for filter taps.
>>
>> -- Cinaed
>>
>>
>> On 09/26/2017 05:45 PM, Chad Spooner wrote:
>>> All:
>>>
>>> I've got a working signal generator in GRC that uses the FFT Filter
>>> block. In the Taps
>>> field of this block, I've hand-entered a length-31 sequence that is an
>>> MLSR sequence.
>>> These sequences can be generated using the GRC block GLFRS Source as well.
>>>
>>> What I would like to do is call GLFSR from within  the FFT Filter Taps
>>> field with arguments
>>> that depend on a Parameter. Specifically, the Degree parameter of GLFSR
>>> would
>>> be tied to a Parameter in the flowgraph.
>>>
>>> I've been searching around the web for a way to do this, but I can't
>>> seem to find how
>>> to call things like GLFSR as opposed to using the GLFSR block in GRC. My
>>> Google
>>> searches do not seem to contain the correct keywords to get me to the
>>> help I need.
>>>
>>> I'd appreciate any hints, especially links to explanations on the web.
>>>
>>> Thanks!
>>>
>>> Chad
>>>
>>> -- 
>>> Chad M. Spooner
>>> NorthWest Research Associates
>>> 301 Webster Street
>>> Monterey, CA 93940
>>> address@hidden
>>> 831 582 4904
>>> cyclostationary.blog
>>>
>>>
>>>
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>>
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