Calculates low frequency power spectrum of vocalic interval of speech signal. Following method of Tilsen & Johnson (2008)
fft_spectrum(signal, f, f_out = 80, padding = 512)Returns a matrix with columns `freq` (frequency in Hz) and `pwr` (spectral power).
a speech signal
sampling frequency
output sampling frequency. Signal will be lowpass filtered at f_out/2
length to zero pad signal to. If signal is longer than padding, this will be increased.
Tilsen, S., & Johnson, K. (2008). Low-frequency Fourier analysis of speech rhythm. The Journal of the Acoustical Society of America, 124(2), EL34–EL39. doi:10.1121/1.2947626
fft_spectro