Crate spectrum_analyzer

An easy to use and fast no_std library (with alloc) to get the frequency spectrum of a digital signal (e.g. audio) using FFT.

Examples

Scaling via dynamic closure

use spectrum_analyzer::{samples_fft_to_spectrum, FrequencyLimit};
// get data from audio source
let samples = vec![0.0, 1.1, 5.5, -5.5];
let res = samples_fft_to_spectrum(
        &samples,
        44100,
        FrequencyLimit::All,
        Some(&|val, info| val - info.min),
);

Scaling via static function

use spectrum_analyzer::{samples_fft_to_spectrum, FrequencyLimit};
use spectrum_analyzer::scaling::divide_by_N_sqrt;
// get data from audio source
let samples = vec![0.0, 1.1, 5.5, -5.5];
let res = samples_fft_to_spectrum(
        &samples,
        44100,
        FrequencyLimit::All,
        // Recommended scaling/normalization by `rustfft`.
        Some(&divide_by_N_sqrt),
);

Modules

error

Errors related to the spectrum analysis via FFT. Most probably, the errors will result in wrong input data, before the actual calculation has begun.

scaling

This module contains convenient public transform functions that you can use as parameters in samples_fft_to_spectrum for scaling the frequency value (the FFT result).

windows

Several window functions which you can apply before doing the FFT. For more information:

Structs

FrequencySpectrum

Convenient wrapper around the processed FFT result which describes each frequency and its value/amplitude from the analyzed samples.

Enums

FrequencyLimit

Can be used to specify a desired frequency limit.

FrequencyLimitError

Possible errors when creating a FrequencyLimit-object.

Functions

samples_fft_to_spectrum

Takes an array of samples (length must be a power of 2), e.g. 2048, applies an FFT (using the specified FFT implementation) on it and returns all frequencies with their volume/magnitude.

Type Aliases

Frequency

A frequency in Hertz. A convenient wrapper type around f32.

FrequencyValue

The value of a Frequency in a frequency spectrum. Also called the magnitude.