scipy.signal.decimate¶

scipy.signal.
decimate
(x, q, n=None, ftype='iir', axis=1, zero_phase=None)[source]¶ Downsample the signal after applying an antialiasing filter.
By default, an order 8 Chebyshev type I filter is used. A 30 point FIR filter with Hamming window is used if ftype is ‘fir’.
Parameters: x : ndarray
The signal to be downsampled, as an Ndimensional array.
q : int
The downsampling factor. For downsampling factors higher than 13, it is recommended to call
decimate
multiple times.n : int, optional
The order of the filter (1 less than the length for ‘fir’). Defaults to 8 for ‘iir’ and 30 for ‘fir’.
ftype : str {‘iir’, ‘fir’} or
dlti
instance, optionalIf ‘iir’ or ‘fir’, specifies the type of lowpass filter. If an instance of an
dlti
object, uses that object to filter before downsampling.axis : int, optional
The axis along which to decimate.
zero_phase : bool, optional
Prevent phase shift by filtering with
filtfilt
instead oflfilter
when using an IIR filter, and shifting the outputs back by the filter’s group delay when using an FIR filter. A value ofTrue
is recommended, since a phase shift is generally not desired. UsingNone
defaults toFalse
for backwards compatibility. This default will change toTrue
in a future release, so it is best to set this argument explicitly.New in version 0.18.0.
Returns: y : ndarray
The downsampled signal.
See also
resample
 Resample up or down using the FFT method.
resample_poly
 Resample using polyphase filtering and an FIR filter.
Notes
The
zero_phase
keyword was added in 0.18.0. The possibility to use instances ofdlti
asftype
was added in 0.18.0.