T4.1 - FFT of raw data from semi-stationary periodic signal

TRNPep

Member
Hi everyone,
I was wondering if any of you could help me find an algorithm for FFT on T4.1 WITHOUT using the audio boad. I need to process a repeating falling exponential wich in time can elong or shorten his time constant (it is a signal from a pulse induction metal detector, feeded to the teensy via an external precision ADC). Since I am deisgning the whole sistem, I am free to set all the parameters as I want. Problem is, i really didn't find any algorithm that allows me to process the FFT from raw data! That's really the only thing I need, a base code or a library that allows me to process those data, I will think about all the parameters setting to fit my specific case.

Beside that, has anyone ever measured the time constant of a falling exponential? Is there any curve-fitting library witch i can use?

Thaks guys!
 
As all FFT work with raw data (whatever "raw" exactly means),"i really didn't find any algorithm that allows me to process the FFT from raw data" translates to "i really cant find code that I can copy and paste and works out the box".

The net is full of FFT in C.
 
Of course there are tons of algorithm for fft, but maybe there was something optimized for the T4.1. Clearly if you're asking me if the audio library is any good this means that i misanderstood something. I thought that to use that library i nedeed the audio board. I will document better on the audio library, thank you
 
I thought that to use that library i nedeed the audio board.
Somehow you have to get the data into Teensy. Your ADC will most likely use I2S, TDM or similar. All supported by audio board.
Also check the FFT in the audio library for an example, if you write everything from scratch.
 
ince I am deisgning the whole sistem, I am free to set all the parameters as I want.
maybe there was something optimized for the T4.1.
So speed is not a criterion. I would suggest getting it working first and optimize later. That's usually the best approach.
 
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