obspy.signal.cpxtrace.normalized_envelope

normalized_envelope(data, fs, smoothie, fk)[source]

Normalized envelope of a signal.

Computes the normalized envelope of the given data which can be windowed or not. In order to obtain a normalized measure of the signal envelope the instantaneous bandwidth of the smoothed envelope is normalized by the Nyquist frequency and is integrated afterwards.

The time derivative of the normalized envelope is returned if input data are windowed only.

Parameters:

  • data (ndarray) – Data to make normalized envelope of.

  • fs – Sampling frequency.

  • smoothie – Window length for moving average.

  • fk – Coefficients for calculating time derivatives (calculated via central difference).

Returns:

Anorm[, dAnorm] - Normalized envelope of input data, Time derivative of normalized envelope (windowed only).