Re: how to auto detect peak frequency in QT FFT sink

[Kyle A Logue]

just did a quick test, couldn't be simpler

max_i reports the argmax of the fft, with wrapping

So in the above example:

• 1 kHz -> 1
• 5.5 kHz -> 5
• -1 kHz -> 31
• -8 KHz -> 24

increase from 32 to increase resolution

Kyle

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From: james jordan <james.jordan.999@hotmail.com>
Sent: Monday, November 30, 2020 18:37
To: Kyle A Logue <kyle.a.logue@aero.org>; discuss-gnuradio@gnu.org <Discuss-gnuradio@gnu.org>
Subject: Re: how to auto detect peak frequency in QT FFT sink

 

Hi Kyle,

is there any document for how to use the block in gr-fhss-utils especially for fft peak block. what is the two output of fft peak?

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From: Kyle A Logue <kyle.a.logue@aero.org>
Sent: Friday, November 20, 2020 12:26 AM
To: james jordan <james.jordan.999@hotmail.com>; discuss-gnuradio@gnu.org <Discuss-gnuradio@gnu.org>
Subject: Re: how to auto detect peak frequency in QT FFT sink

 

cmake version is too low so i can not build gr-fhss

gr-fhss has a 3.7 and a 3.8 version if you check the tags on github

how to store max result to a gui label?

qt-number-sink maybe

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From: james jordan <james.jordan.999@hotmail.com>
Sent: Wednesday, November 18, 2020 22:07
To: Kyle A Logue <kyle.a.logue@aero.org>; discuss-gnuradio@gnu.org <Discuss-gnuradio@gnu.org>
Subject: Re: how to auto detect peak frequency in QT FFT sink

 

Hi Kyle,

Thanks. my cmake version is too low so i can not build gr-fhss. i try to use fft->max but how to store max result to a gui label?

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From: Kyle A Logue <kyle.a.logue@aero.org>
Sent: Thursday, November 19, 2020 4:05 AM
To: james jordan <james.jordan.999@hotmail.com>; discuss-gnuradio@gnu.org <Discuss-gnuradio@gnu.org>
Subject: Re: how to auto detect peak frequency in QT FFT sink

 

2 things that come to mind:

1. stream -> fft -> argmax
2. in sandia fhss utilities they have an FFT Peak block that does what you want

https://github.com/sandialabs/gr-fhss_utils

Kyle Logue

Senior Engineering Specialist

⚝ The Aerospace Corporation

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From: Discuss-gnuradio <discuss-gnuradio-bounces+kyle.a.logue=aero.org@gnu.org> on behalf of james jordan <james.jordan.999@hotmail.com>
Sent: Monday, November 16, 2020 19:09
To: discuss-gnuradio@gnu.org <Discuss-gnuradio@gnu.org>
Subject: how to auto detect peak frequency in QT FFT sink

 

Hi all,

i want to see the fft of the signal and also want to detect the peak frequency if there is a peak signal.

how to achieve this?