Engee documentation

Filter CE

The RF filter model.

blockType: SubSystem

filter ce

Path in the library:

/RF/Circuit Envelope/Elements/Filter CE

Description

Block Filter CE simulates two types of RF filters:

  • Butterworth filters have the most flat amplitude—frequency response (frequency response) in the passband and are monotonous in general; this smoothness is achieved by reducing the steepness of the decline;

  • Chebyshev filters — Chebyshev filters of the first kind have frequency response pulsations of the same magnitude in the passband and monotonic in the delay band.

To filter complex RF broadband signals in Engee, use the block Filter.

Ports

Conserving

# 1 — electrical port
electricity

Details

The electrical port.

Program usage name

1

# 2 — electrical port
electricity

Details

The electrical port.

Program usage name

2

Parameters

Main group

# Design method: — filter design method
Butterworth | Chebyshev

Details

The filter modeling method, defined as:

  • Butterworth — simulates a Butterworth filter with the type specified in the parameter Filter type:, and the model specified in the parameter Implementation:;

  • Chebyshev — simulates a Chebyshev filter with the type specified in the parameter Filter type:, and the model specified in the parameter Implementation:.

Values

Butterworth | Chebyshev
Default value

Butterworth
Program usage name

filterDesign
Tunable

No
Evaluatable

Yes

# Filter type: — filter response type
Lowpass | Highpass | Bandpass | Bandstop

Details

The type of filter response, set as:

  • Lowpass — simulates a low-pass filter, the design method of which is specified in the parameter Design method:;

  • Highpass — simulates a high-pass filter, the design method of which is specified in the parameter Design method:;

  • Bandpass — simulates a bandpass filter, the design method of which is specified in the parameter Design method:;

  • Bandstop — simulates a notch filter, the design method of which is specified in the parameter Design method:.

Values

Lowpass | Highpass | Bandpass | Bandstop
Default value

Lowpass
Program usage name

filterType
Tunable

No
Evaluatable

Yes

# Implementation: — realization
LC Tee | LC Pi

Details

The implementation specified as:

  • LC Tee — simulation of an analog filter using a concentrated LC Tee structure, if for the parameter Design method: the value is set Butterworth or Chebyshev;

  • LC Pi — simulation of an analog filter using a concentrated LC Pi structure, if for the parameter Design method: the value is set Butterworth or Chebyshev.

By default for the parameter Implementation: the value is set LC Tee for the Butterworth or Chebyshev filter.

Due to causal relationships, a delay equal to half the duration of the pulse response is taken into account for both reflected and transmitted signals. This delay will degrade the filter performance if the source and load resistances differ from the values specified in the filter parameters.
Values

LC Tee | LC Pi
Default value

LC Tee
Program usage name

implementation
Tunable

No
Evaluatable

Yes

# Implement using filter order — enable implementation using filter order

Details

Check this box to implement the filter order manually.

Default value

true (switched on)
Program usage name

isOrder
Tunable

No
Evaluatable

Yes

# Filter order: — filter order

Details

The filter order, set as a scalar in the range [2, 60]. If for the parameter Filter type: value selected Lowpass or Highpass, specify the number of concentrated reactive elements. If for the parameter Filter type: value selected Bandpass or Bandstop, specify twice as many elements (L and C).

For Chebyshev filters of even order, the resistance ratio is to implement the Tee network and to implement the Pi network.

where

  • — uneven bandwidth in dB.

Dependencies

To use this option, check the box Implement using filter order.

Default value

3
Program usage name

filterOrder
Tunable

No
Evaluatable

Yes

# Passband frequency: — bandwidth frequency of low- and high-pass filters

Details

The bandwidth frequency for low- and high-pass filters, set as a scalar in Hz. The default value of this parameter depends on the selected parameter value. Filter type:. The default values are shown in this table.

Filter type: Default bandwidth frequency value

Lowpass

1 GHz

Highpass

2 GHz

Dependencies

To use this parameter, set for the parameter Filter type: meaning Lowpass or Highpass.

Default value

1.0e9
Program usage name

passFreq_lp
Tunable

No
Evaluatable

Yes

# Passband attenuation (dB): — bandwidth attenuation

Details

Bandwidth attenuation, specified as a scalar in dB. For bandpass filters, this value is applied equally to both edges of the bandwidth.

Default value

3.010299956639812
Program usage name

passAttenuation
Tunable

No
Evaluatable

Yes

# Source impedance (Ohm): — input resistance of the source

Details

The input resistance of the source, set as a scalar in ohms.

Default value

50
Program usage name

sourceImp
Tunable

No
Evaluatable

Yes

# Load impedance (Ohm): — output load resistance

Details

The output load resistance, set as a scalar in ohms.

Default value

50
Program usage name

loadImp
Tunable

No
Evaluatable

Yes

# Passband frequencies: — bandwidth frequencies for bandpass filters

+

Details

The bandwidth frequencies for bandpass filters, specified as a two-element vector in Hz. This option is not available for notch filters.

Dependencies

To use this parameter, set for the parameter Filter type: meaning Bandpass.

Default value

[2.0e9, 3.0e9]
A name for programmatic use

passFreq_bp

# Stopband frequency: — the frequency of the delay band of the low and high pass filters

+

Details

The frequency of the delay band for low- and high-pass filters, set as a scalar in Hz. The default value of this parameter depends on the selected parameter value. Filter type:. The default values are shown in this table.

Filter type: Default delay band frequency value

Lowpass

2 GHz

Highpass

1 GHz

Dependencies

To use this option, uncheck the box. Implement using filter order and set for the parameter Filter type: meaning Lowpass or Highpass.

Default value

2.0e9
A name for programmatic use

stopFreq_lp

# Stopband frequencies: — delay band frequencies for notch filters

+

Details

The delay band frequencies for bandpass filters, set as a two-element vector in Hz. This option is not available for bandpass filters.

Dependencies

To use this parameter, set for the parameter Filter type: meaning Bandstop.

Default value

[2.1e9, 2.9e9]
A name for programmatic use

stopFreq_bs

# Stopband attenuation (dB): — attenuation in the delay band

Details

Attenuation in the delay band, set as a scalar in dB. For notch filters, this value is applied equally to both edges of the delay band.

Dependencies

To use this parameter, set for the parameter Filter type: meaning Bandstop.

Default value

40
A name for programmatic use

stopAttenuation

Additional Info

Frequency characteristics

Details
Filter type: Frequency response Designations

Lowpass

filter ce 1 en

— bandwidth frequency

— frequency of the delay band

— bandwidth attenuation @

— attenuation in the delay band @

Highpass

filter ce 2 en

Bandpass

filter ce 3 en

— bandwidth frequencies

— frequency of the delay band

— attenuation in the bandwidth at specified bandwidth frequencies

— attenuation in the delay band at the specified frequencies of the delay band

Bandstop

filter ce 4 en

filter ce 5 en

Filter definition parameters and design tips

Details

The table shows all the parameters necessary for the correct design of each filter.

Lowpass Highpass Bandpass Bandstop

Butterworth

Order, ,

Order, ,

Order, ,

Order, ,

, , ,

, , ,

, , ,

, , ,

Chebyshev

Order, ,

Order, ,

Order, ,

Order, ,

, , ,

, , ,

, , ,

, , ,

The following designations are used in this table:

  • — bandwidth frequency;

  • — attenuation in the bandwidth / unevenness in the bandwidth;

  • — frequency of the delay band;

  • — attenuation in the delay band / unevenness in the delay band.

The unevenness (ripple) in the bandwidth or delay is analyzed as attenuation in the bandwidth or delay, respectively.

Additional design tips

Details

Additional design tips.

Lowpass Highpass Bandpass Bandstop

Butterworth

Order, , Auxiliary (numerator polynomial 21)

Order, , Auxiliary (numerator polynomial 21, Wx)

Order, , Auxiliary (Wx)

Chebyshev

Order, , Auxiliary (numerator polynomial 21)

Order, , Auxiliary (fourth power of the numerator 21, Wx)

Literature

  1. Kendall Su, Analog Filters, Second Edition.

  2. Louis Weinberg, Network Analysis and Synthesis, Huntington, New York: Robert E. Krieger Publishing Company, 1975.

  3. Larry D. Paarmann, Design and Analysis of Analog Filters, A Signal Processing Perspective with MATLAB® Examples, Kluwer Academic Publishers, 2001.

  4. Michael G. Ellis, SR., Electronic Filter Analysis and Synthesis, Norwood, MA: Artech House, 1994.

  5. Anatol I. Zverev, Handbook of Filter Synthesis, Hoboken, NJ: John Wiley & Sons, 2005.