Engee documentation

Analog Filter Design

Design and implementation of analog filters.

blockType: AnalogFilterDesign

analog filter design

Path in the library:

/Signal Operations/Filters/Filter Designs/Analog Filter Design

Description

Block Analog Filter Design designs and implements Butterworth filters, Chebyshev filters of the first kind, Chebyshev filters of the second kind, Bessel filters or elliptical filters for different types of frequency response: high-pass filters, low-pass filters, bandpass filters or notch filters.

In the parameters Design method and Filter type It is necessary to specify the filter design and the type of frequency response. For each combination of the filter design and the type of frequency response, the corresponding parameter group is displayed. For more information, see The combination table of the filter design and the type of frequency response.

Block Analog Filter Design uses a representation of the filter in the state space and applies the filter using a block State-Space.

Ports

Input

# IN_1 — Input signal
scalar

Details

The input signal for the block, specified as a real scalar in a sample format, is continuous in real time.

Data types

Float64
Complex numbers support

I don’t

Output

# OUT_1 — Output signal
scalar

Details

The filtered output signal returned as a scalar.

Data types

Float64
Complex numbers support

I don’t

Parameters

Main

# Design method — filter design
Butterworth | Chebyshev I | Chebyshev II | Elliptic | Bessel

Details

The filter design methods are as follows:

  • Butterworth — the amplitude-frequency response of the Butterworth filter has a maximally flat bandwidth and is generally monotonous.

  • Chebyshev I — the amplitude-frequency response of the Chebyshev filter of the first kind has uniform pulsations in the passband and is monotonous in the delay band.

  • Chebyshev II — the amplitude-frequency response of the Chebyshev filter of the second kind is monotonous in the passband and has uniform pulsations in the delay band.

  • Elliptic — the amplitude-frequency response of the elliptical filter has uniform ripples in both the passband and the delay band.

  • Bessel — the amplitude-frequency response of the Bessel filter has a maximally flat bandwidth and is generally monotonous. The filter has a maximally flat linear phase-frequency response.

Values

Butterworth | Chebyshev I | Chebyshev II | Elliptic | Bessel
Default value

Butterworth
Program usage name

DesignMethod
Tunable

No
Evaluatable

No

# Filter type — type of frequency response
Lowpass | Highpass | Bandpass | Bandstop

Details

Frequency response type, options to choose from:

  • Lowpass — low pass filter.

  • Highpass — high-pass filter.

  • Bandpass — bandpass filter.

  • Bandstop — a notch filter.

Values

Lowpass | Highpass | Bandpass | Bandstop
Default value

Lowpass
Program usage name

FilterType
Tunable

No
Evaluatable

No

# Filter order — filter order
Int64 integer

Details

The order of the filter, if for the parameter Filter type the value is set:

  • Lowpass;

  • Highpass.

The order of the generated filter is twice the set value if for the parameter Filter type the value is set:

  • Bandpass;

  • Bandstop.

Default value

8
Program usage name

FilterOrder
Tunable

No
Evaluatable

Yes

# Passband edge frequency, rad/s — the cutoff frequency that determines the bandwidth
Float64 real number

Details

The cutoff frequency that determines the bandwidth. The unit of measurement is rad/sec.

Dependencies

To use this parameter, set for the parameter Design method meaning Butterworth, Chebyshev I, Elliptic or Bessel, and for the parameter Filter type meaning Lowpass or Highpass.

Default value

30.0
Program usage name

PassEdgeFreq
Tunable

No
Evaluatable

Yes

# Lower passband edge frequency, rad/s — the frequency of the lower limit of the bandwidth
Float64 real number

Details

The frequency of the lower limit of the bandwidth. The unit of measurement is rad/sec.

Dependencies

To use this parameter, set for the parameter Design method meaning Butterworth, Chebyshev I, Elliptic or Bessel, and for the parameter Filter type meaning Bandpass or Bandstop.

Default value

30.0
Program usage name

LowPassEdgeFreq
Tunable

No
Evaluatable

Yes

# Upper passband edge frequency, rad/s — the frequency of the upper limit of the bandwidth
Float64 real number

Details

The frequency of the upper limit of the bandwidth. The unit of measurement is rad/sec.

Dependencies

To use this parameter, set for the parameter Design method meaning Butterworth, Chebyshev I, Elliptic or Bessel, and for the parameter Filter type meaning Bandpass or Bandstop.

Default value

60.0
Program usage name

UpPassEdgeFreq
Tunable

No
Evaluatable

Yes

# Stopband edge frequency, rad/s — the cutoff frequency that defines the delay band
Float64 real number

Details

The cutoff frequency that defines the delay band. The unit of measurement is rad/sec.

Dependencies

To use this parameter, set for the parameter Design method meaning Chebyshev II, and for the parameter Filter type meaning Lowpass or Highpass.

Default value

30.0
Program usage name

StopEdgeFreq
Tunable

No
Evaluatable

Yes

# Lower stopband edge frequency, rad/s — frequency of the lower limit of the delay band
Float64 real number

Details

The frequency of the lower limit of the delay band. The unit of measurement is rad/sec.

Dependencies

To use this parameter, set for the parameter Design method meaning Chebyshev II, and for the parameter Filter type meaning Bandpass or Bandstop.

Default value

30.0
Program usage name

LowStopEdgeFreq
Tunable

No
Evaluatable

Yes

# Upper stopband edge frequency, rad/s — frequency of the upper limit of the delay band
Float64 real number

Details

The frequency of the upper limit of the delay band. The unit of measurement is rad/sec.

Dependencies

To use this parameter, set for the parameter Design method meaning Chebyshev II, and for the parameter Filter type meaning Bandpass or Bandstop.

Default value

60.0
Program usage name

UpStopEdgeFreq
Tunable

No
Evaluatable

Yes

# Passband ripple, dB — ripples in the bandwidth
Float64 real number

Details

Ripples of the amplitude-frequency response in the bandwidth. The unit of measurement is dB.

Dependencies

To use this parameter, set for the parameter Design method meaning Chebyshev I or Elliptic.

Default value

2.0
Program usage name

PassRipple
Tunable

No
Evaluatable

Yes

# Stopband attenuation, dB — attenuation in the delay band
Float64 real number

Details

Attenuation in the delay band. The unit of measurement is dB.

Dependencies

To use this parameter, set for the parameter Design method meaning Chebyshev II or Elliptic.

Default value

20.0
Program usage name

StopAttenuation
Tunable

No
Evaluatable

Yes

Additional Info

The combination table of the filter design and the type of frequency response

Details

This table lists the available parameters for each combination of filter design and frequency response type. For configurations with low or high pass filters, these parameters include:

  • The cutoff frequency that determines the bandwidth, ;

  • The cutoff frequency that defines the delay band, ;

  • Ripples in the bandwidth ;

  • Attenuation in the delay band .

For configurations with a bandpass or notch filter, these parameters include:

  • Frequencies of the lower and upper limits of the bandwidth and ;

  • Frequencies of the lower and upper limits of the delay band and ;

  • Ripples in the bandwidth ;

  • Attenuation in the delay band .

The units of frequency measurement are rad/s, and the frequency ripple and attenuation are dB.

Filter design Low Pass filter High-pass filter Bandpass filter Notch filter

Butterworth

Order,

Order,

Order, ,

Order, ,

Chebyshev I

Order, ,

Order, ,

Order, , ,

Order, , ,

Chebyshev II

Order, ,

Order, ,

Order, , ,

Order, , ,

Elliptic

Order, , ,

Order, , ,

Order, , , ,

Order, , , ,

Bessel

Order,

Order,

Order, ,

Order, ,

Literature

  1. Antoniou, A. Digital Filters: Analysis, Design, and Applications. 2nd ed. New York, NY: McGraw-Hill, 1993

Examples