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### Topic: HELP WITH THE LIBRARY FFT (Read 1 time)previous topic - next topic

#### boganazhapa

##### Sep 05, 2013, 09:48 pm
Hello world arduino

I'm in a project is to demonstrate and plot the spectral diagram of an analog signal and not to start.? ..... =(

First of all I read about arduino Seller FFT and see that is the only option to apply, but my problem is, as I can use it and do not know how?? .... =(.

I would like some help or some examples of how to use and get the amplitude and phase of each analog signal with this program because I need to extract all the amplitudes and phases of all the harmonics existing one signal and calculate the THD.

Thank you thank you

#### Erdin

#1
##### Sep 06, 2013, 12:24 pm
A link to the library ?
What is your sketch ?

When you also post the question in another language, you could add a link to it.

#### boganazhapa

#2
##### Sep 15, 2013, 05:26 am
Hi, I'm new to programming in arduino

This is the library:

https://code.google.com/p/neuroelec/downloads/detail?name=ffft_Library.zip&can=2&q=

I do not know how to use the code,

I want to acquire analog 6-channel, and the code provided below is valid for 6 analog channels:

ISR(ADC_vect)
{
if (position >= FFT_N)
return;

capture[position] = ADC + zero;
if (capture[position] == -1 || capture[position] == 1)
capture[position] = 0;

position++;
}

also
void adcCalb(){
Serial.println("Start to calc zero");
long midl = 0;
// get 2 meashurment at 2 sec
// on ADC input must be NO SIGNAL!!!
for (byte i = 0; i < 2; i++)
{
position = 0;
delay(100);
midl += capture[0];
delay(900);
}
zero = -midl/2;
Serial.println("Done.");
}

And I do not understand if the prescale is activated for all analog ports, or is necessary to activate for each port.

Thanks you

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