Crate spectrum_analyzer

source ·
Expand description

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 crate::samples_fft_to_spectrum for scaling the frequency value (the FFT result). They act as “idea/inspiration”. Feel free to either compose them or create your own derivation from them.
  • windows
    Several window functions which you can apply before doing the FFT. For more information:

Structs

Enums

  • FrequencyLimit
    Can be used to specify a desired frequency limit. If you know that you only need frequencies f <= 1000Hz, 1000 <= f <= 6777, or 10000 <= f, then this can help you to accelerate overall computation speed and memory usage.
  • 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 Definitions