Analog Filter Design
Design and implementation of analogue filters.
Description
The Analog Filter Design block designs and implements Butterworth, Chebyshev of genus I, Chebyshev of genus II, Bessel or elliptic filters for different types of frequency response: high-pass filters, low-pass filters, bandpass filter or bandpass filter.
In the Design method and Filter type parameters you must specify the filter design and the type of frequency response. For each combination of filter design and frequency response type, the corresponding parameter group is displayed. For more details, please refer to the section [Таблица комбинации конструкции фильтра и типа частотной характеристики].
The Analog Filter Design block uses a state-space representation of the filter and applies the filter using the State-Space block .
Parameters
Design method - filter design
Butterworth (by default) | Chebyshev I | Chebyshev II | Elliptic | Bessel
The filter design methods are as follows:
-
Butterworth- The amplitude-frequency response of a Butterworth filter has a maximally flat passband and is generally monotonic. -
Chebyshev I- the amplitude-frequency response of the Chebyshev filter of the first kind has uniform ripples in the pass band and is monotonic in the delay band. -
Chebyshev II- the amplitude-frequency characteristic of Chebyshev filter of the II kind is monotonic in the pass band and has uniform ripples in the delay band. -
Elliptic- the amplitude-frequency response of the elliptic filter has uniform ripples both in the passband and in the delay band. -
Bessel- the amplitude-frequency response of the Bessel filter has a maximally flat passband and is generally monotonic. The filter has a maximally flat linear phase-frequency response.
Filter type - type of frequency response
Lowpass (by default) | Highpass | Bandpass | Bandstop
Frequency response type, options to select:
-
Lowpass- lowpass filter. -
Highpass- high pass filter. -
Bandpass- bandpass filter. -
Bandstop- bandpass filter.
Filter order - filter order
8 (By default) | scalar
Filter order, if Filter type is set to a value:
-
Lowpass; -
Highpass.
The order of the generated filter is twice the specified value if the Filter type parameter is set:
-
Bandpass; -
Bandstop.
Passband edge frequency (rad/s) - the cut-off frequency that defines the passband
30 (By default) | scalar.
The cut-off frequency that defines the passband. The unit of measurement is rad/s.
Dependencies
To use this parameter, set the Design method parameter to Butterworth, Chebyshev I, Elliptic or Bessel and the Filter type parameter to Lowpass or Highpass.
Lower passband edge frequency (rad/s) - the frequency of the lower passband edge frequency
30 (By default) | scalar.
Lower passband edge frequency. The unit of measurement is rad/s.
Dependencies
To use this parameter, set Design method to Butterworth, Chebyshev I, Elliptic or Bessel and Filter type to Bandpass or Bandstop.
Upper passband edge frequency (rad/s) - frequency of the upper passband edge frequency
60 (By default) | scalar.
Upper passband edge frequency. The unit of measurement is rad/s.
Dependencies
To use this parameter, set Design method to Butterworth, Chebyshev I, Elliptic or Bessel and Filter type to Bandpass or Bandstop.
Stopband edge frequency (rad/s) - the cut-off frequency that defines the delay bandwidth
30 (By default) | scalar.
The cutoff frequency that defines the delay band. The unit of measurement is rad/s.
Dependencies
To use this parameter, set the Design method parameter to Chebyshev II and the Filter type parameter to Lowpass or Highpass.
Lower stopband edge frequency (rad/s) - frequency of the lower stopband edge frequency
30 (By default) | scalar
Frequency of the lower boundary of the delay band. The unit of measurement is rad/s.
Dependencies
To use this parameter, set the Design method parameter to Chebyshev II and the Filter type parameter to Bandpass or Bandstop.
Upper stopband edge frequency (rad/s) - frequency of the upper stopband edge frequency
60 (By default) | scalar
Frequency of the upper boundary of the delay band. The unit of measurement is rad/s.
Dependencies
To use this parameter, set the Design method parameter to Chebyshev II and the Filter type parameter to Bandpass or Bandstop.
Passband ripple in dB - ripple in bandwidth
2 (By default) | scalar.
The ripple of the amplitude-frequency response in the passband. The unit of measurement is dB.
Dependencies
To use this parameter, set the Design method parameter to Chebyshev I or Elliptic.
Stopband attenuation in dB - attenuation in delay bandwidth
20 (By default) | scalar.
Attenuation in the delay band. The unit of measurement is dB.
Dependencies
To use this parameter, set the Design method parameter to Chebyshev II or Elliptic.
Table of combination of filter design and frequency response type
This table lists the available parameters for each combination of filter design and frequency response type. For low-pass or high-pass filter configurations, these parameters include:
-
Cutoff frequency, which defines the bandwidth .
-
Cutoff frequency, which defines the passband .
-
Bandwidth ripple .
-
Attenuation in the delay band .
For configurations with bandpass or bandpass filter, these parameters include:
-
Lower and upper bandwidth frequencies and .
-
Frequencies of the lower and upper boundary of the delay band and .
-
Bandwidth ripple .
-
Attenuation in the delay band .
The units of frequency are rad/s and frequency ripple and attenuation are dB.
| Filter Design | Low Pass Filter | High Pass Filter | Bandpass Filter | Regret Filter |
|---|---|---|---|---|
*Butterworth filter. |
Order, |
Order, |
Order, , |
Order, , |
*Chebyshev filter of the first kind. |
Order, , |
Order, , |
Order, , , |
Order, , , |
*Chebyshev filter of genus II * |
Order, , |
Order, , |
Order, , , |
Order, , , |
Elliptical filter |
Order, , , |
Order, , , |
Order, , , , |
Order, , , , |
*Bessel filter |
Order, |
Order, |
Order, , |
Order, , |
References
Antoniou, A. Digital Filters: Analysis, Design, and Applications. 2nd ed. New York, NY: McGraw-Hill, 1993