freq_vector_scale (pyleoclim.utils.wavelet.freq_vector_scale)

pyleoclim.utils.wavelet.freq_vector_scale(ts, dj=0.25, s0=None, j1=None, mother='MORLET', param=None)[source]

Return the frequency vector based on scales for wavelet analysis. This function is adapted from Torrence and Compo

Parameters

ts (numpy.array) – The time axis for the timeseries
dj (float, optional) – The spacing between discrete scales. The default is 0.25. A smaller number will give better scale resolution, but be slower to plot.
s0 (float, optional) – the smallest scale of the wavelet. The default is None, representing 2*dT.
j1 (float, optional) – the number of scales minus one. Scales range from S0 up to S0*2**(J1*DJ), to give a total of (J1+1) scales. The default is None, which represents (LOG2(N DT/S0))/DJ.
mother (string, optional) – the mother wavelet function. The default is ‘MORLET’. Options are: ‘MORLET’, ‘PAUL’, or ‘DOG’
param (flaot, optional) –
the mother wavelet parameter. The default is None since it varies for each mother
- For ‘MORLET’ this is k0 (wavenumber), default is 6.
- For ‘PAUL’ this is m (order), default is 4.
- For ‘DOG’ this is m (m-th derivative), default is 2.

Returns

freq – the frequency vector

Return type

array