FFT Library / arduinoFFT Library / FHT Library

FFT: Fast Fourier Transform 快速傅立葉轉換

介紹 https://www.norwegiancreations.com/2017/08/what-is-fft-and-how-can-you-implement-it-on-an-arduino/

A more recent (and faster) library version is FHT (Fast Fartley Transform) by Open Music Labs: http://wiki.openmusiclabs.com/wiki/ArduinoFHT

Or the FFT library by Open Music Labs: http://wiki.openmusiclabs.com/wiki/ArduinoFFT

Or the official arduinoFFT library which allows seemingly more flexibility: https://www.arduinolibraries.info/libraries/arduino-fft

• 注意，這兩個函式庫的範例使用了cli()與sei()，會影響到arduino的運作時間。