delayseq.py 文件源码

def delayseq(x, delay_sec:float, fs:int):
    """
    x: input 1-D signal
    delay_sec: amount to shift signal [seconds]
    fs: sampling frequency [Hz]

    xs: time-shifted signal
    """

    assert x.ndim == 1, 'only 1-D signals for now'

    delay_samples = delay_sec*fs
    delay_int = round(delay_samples)

    nfft = nextpow2(x.size+delay_int)

    fbins = 2*pi*ifftshift((arange(nfft)-nfft//2))/nfft

    X = fft(x,nfft)
    Xs = ifft(X*exp(-1j*delay_samples*fbins))

    if isreal(x[0]):
        Xs = Xs.real

    xs = zeros_like(x)
    xs[delay_int:] = Xs[delay_int:x.size]

    return xs