comnum.fourth_power_foe#

comnum.fourth_power_foe(x, fs, *, m=4, refined=True)#

Frequency offset of an m-fold symmetric signal by its m-th power spectrum (OptiCommPy fourthPowerFOE with refined=False).

Parameters:

  • x (array_like) – signal at one sample per symbol.

  • fs (float) – its sampling rate (Hz).

  • m (int) – the symmetry (4 for QAM).

  • refined (bool) – refine the periodogram peak by a golden-section search between the neighbouring bins (the default, as the foe block); otherwise the estimate is on the FFT grid, as OptiCommPy’s.

Returns:

the corrected signal and the offset (Hz).

Return type:

tuple[numpy.ndarray, float]

Raises:

ValueError – for an invalid parameter or input (the message names it).