[Discuss-gnuradio] Filter bank and massive “DDD” messages

[Luis Grajales]

Hi,

I'm trying to filter 14 frequency bands (channels), which are dispersing within spectrum of 25 MHz (from 2 MHz - 27 MHz to be more specific) and each band has a different bandwidth. For example:  1th channel with 198 KHz (bandwidth), 2nd channel with 360 kHz, 3. channel with 650 kHz, and so on.

 

Until now, I have tried 3 scenarios on GRC in order to get these 14 channels and verify that the first step of my project (filtering) is working.  For testing, I used just 4 of the 14 channels to see its functionality and CPU requirement.

 

General configuration:

USRP N200 ----------- channelizer --- [ch1]           -----GUI FFT Sink

                                                ----[ch2 - ch4]   ---- Null Sink

USRP setup ->  samp_rate= 25 MHz, and Center Freq = 14,2 MHz.

Scenario 1: channelizer = 4 band pass filters.

Scenario 2: channelizer = 4 Xlating FIR filters.

Scenario 3: channelizer = Polyphase channelizer,  5 equal channels of 5 MHz.

 

For the 3 configurations I got massive “DDDDD..” at the console output. Moreover:

Scenario 1:  CPU 100% and stop the application.

Scenario 2:  CPU between 75 % and 95 %.

Scenario 3:  CPU between 53 % and 95 %

 

Therefore, I really appreciate if you could give me some tips to avoid this massive “DDD” messages or alternatives to optimize the resource consumption for the filter bank, due to the results showed that the band pass filter (scenario 1) will not be a good option for me, or maybe I did something wrong.

 

In the attached files you will find the 3 different GRC configurations.

Thanks in advance, 

Luis Grajales

bandpass_filters_25Mhz.grc
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PAF_25Mhz.grc
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XFilter_25Mhz.grc
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