в разделе Software
The FFT operations are done in 16-bit fixed-point. These 128 point FFT processes, applying window, butterfly operations and scalar output, could be executed in real-time (within 7.3 msec). This is pretty fast considering it is processed with only a cheap microcontroller. The spectrum bars are displayed in order of fundamental frequency x 0 (DC component), fundamental frequency x 1, x2, x3, ... from left to right. The sampling frequency is 9.6 kHz and the fundamental frequency (frequency resolution) becomes: 9.6k / 128 = 75Hz.