Filters

class pathsim.blocks.filters.ButterworthLowpassFilter(Fc=100, n=2)

Bases: StateSpace

Direct implementation of a low pass butterworth filter block.

Follows the same structure as the ‘StateSpace’ block in the ‘pathsim.blocks’ module. The numerator and denominator of the filter transfer function are generated and then the transfer function is realized as a state space model.

Parameters:

• Fc (float) – corner frequency of the filter in [Hz]

• n (int) – filter order

class pathsim.blocks.filters.ButterworthHighpassFilter(Fc=100, n=2)

Bases: StateSpace

Direct implementation of a high pass butterworth filter block.

Follows the same structure as the ‘StateSpace’ block in the ‘pathsim.blocks’ module. The numerator and denominator of the filter transfer function are generated and then the transfer function is realized as a state space model.

Parameters:

• Fc (float) – corner frequency of the filter in [Hz]

• n (int) – filter order

class pathsim.blocks.filters.ButterworthBandpassFilter(Fc=[50, 100], n=2)

Bases: StateSpace

Direct implementation of a bandpass butterworth filter block.

Follows the same structure as the ‘StateSpace’ block in the ‘pathsim.blocks’ module. The numerator and denominator of the filter transfer function are generated and then the transfer function is realized as a state space model.

Parameters:

• Fc (list[float]) – corner frequencies (left, right) of the filter in [Hz]

• n (int) – filter order

class pathsim.blocks.filters.ButterworthBandstopFilter(Fc=[50, 100], n=2)

Bases: StateSpace

Direct implementation of a bandstop butterworth filter block.

Follows the same structure as the ‘StateSpace’ block in the ‘pathsim.blocks’ module. The numerator and denominator of the filter transfer function are generated and then the transfer function is realized as a state space model.

Parameters:

• Fc (tuple[float], list[float]) – corner frequencies (left, right) of the filter in [Hz]

• n (int) – filter order

class pathsim.blocks.filters.AllpassFilter(fs=100, n=1)

Bases: StateSpace

Direct implementation of a first order allpass filter, or a cascade of n 1st order allpass filters

\[H(s) = \frac{s - 2\pi f_s}{s + 2\pi f_s}\]

where f_s is the frequency, where the 1st order allpass has a 90 deg phase shift.

Parameters:

• fs (float) – frequency for 90 deg phase shift of 1st order allpass

• n (int) – number of cascades