Filter

Model RF Filter

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Library:
RF Blockset / Circuit Envelope / Elements

Description

The Filter block models RF filters of three designs:

Butterworth: Butterworth filters have a magnitude response that is maximally flat in the passband and monotonic overall. This smoothness comes at the price of decreased roll-off steepness.
Chebyshev: Chebyshev Type I filters have ripples of equal magnitude in the passband and monotonic in the stopband.
Inverse Chebyshev: Chebyshev Type II filters have ripples of equal magnitude in the stopband and monotonic in the passband.
Ideal: Ideal filters perfectly allow frequencies in the passband and completely reject frequencies in the stopband.

Parameters

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Main

`Design method` — Simulation type
`Butterworth` (default) | `Chebyshev` | `Inverse Chebyshev` | `Ideal`

Simulation type, specified as one of the following:

Ideal
Simulates an ideal filter of the type specified in Filter type and the model specified in Implementation.
Butterworth
Simulates a Butterworth filter of the type specified in Filter type and the model specified in Implementation.
Chebyshev
Simulates a Chebyshev filter of the type specified in Filter type and the model specified in Implementation.
Inverse Chebyshev
Simulates a inverse Chebyshev filter of the type specified in Filter type and the Transfer function model specified in Implementation.

`Filter type` — Filter type
`Lowpass` (default) | `Highpass` | `Bandpass` | `Bandstop`

Filter type, specified as one of the following:

Lowpass: Simulates a lowpass filter type of the design specified in Design method.
Highpass: Simulates a highpass filter type of the design specified in Design method.
Bandpass: Simulates a bandpass filter type of the design specified in Design method.
Bandstop: Simulates a bandstop filter type of the design specified in Design method.

`Implementation` — Implementation
`LC Tee` | `LC Pi` | `Transfer function` | `Constant per carrier` | `Frequency Domain`

Implementation, specified as one of the following:

LC Tee: Model an analog filter with an LC lumped Tee structure when the Design method is Butterworth or Chebyshev.
LC Pi: Model an analog filter with an LC lumped Pi structure when the Design method is Butterworth or Chebyshev.
Transfer Function: Model an analog filter using two-port S-parameters when the Design method is Butterworth or Chebyshev.
Constant per carrier: Model a filter with either full transmission or full reflection set as constant throughout the entire envelope band around each carrier.The Design method is specified as ideal.
Frequency Domain: Model a filter using convolution with an impulse response. The Design method is specified as ideal. The impulse response is computed independently for each carrier frequency to capture the ideal filtering response. When a transition between full transmission and full reflection of the ideal filter occurs within the envelope band around a carrier, the frequency-domain implementation captures this transition correctly up to a frequency resolution specified in Impulse response duration.

By default, the Implementation is Constant per carrier for an ideal filter and LC Tee for Butterworth or Chebyshev.

Note

Due to causality, a delay of half the impulse response duration is included for both reflected and transmitted signals. This delay will impair the filter performance when the source and load resistances differ from the values specified as filter parameters.

`Passband edge frequency` — Passband edge frequency
`1 GHz` (default) | scalar

Passband edge frequency, specified as a scalar in Hz, kHz, MHz, or GHz.

Dependencies

To enable this parameter, set Design method to Ideal.

`Implement using filter order` — Implement using filter order
`off` (default) | `on`

Select this parameter to implement the filter order manually.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev.

`Filter order` — Filter order
`3` (default) | scalar

Filter order, specified as a scalar. This order is the number of lumped storage elements in lowpass or highpass. In bandpass or bandstop, the number of lumped storage elements are twice the value.

Note

For even order Chebyshev filters, the resistance ratio $\frac{R_{load}}{R_{source}} > R_{ratio}$ for Tee network implementation and $\frac{R_{load}}{R_{source}} < \frac{1}{R_{ratio}}$ for Pi network implementation.

$R_{ratio} = \frac{\sqrt{1 + ε^{2}} + ε}{\sqrt{1 + ε^{2}} - ε}$

where:

$ε = \sqrt{10^{(0.1 R_{p})} - 1}$

R_p is the passband ripple in dB.

Dependencies

To enable this parameter, select Implement using filter order.

`Passband frequency` — Passband frequency for lowpass and highpass filters
scalar

Passband frequency for lowpass and highpass filters, specified as a scalar in Hz, kHz, MHz, or GHz. The default value is 1 GHz for Lowpass filters and 2 GHz for Highpass filters.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev and Filter type to Lowpass or Highpass.

`Passband frequencies` — Passband frequencies for bandpass filters
`[2 3] GHz` (default) | 2-tuple vector

Passband frequencies for bandpass filters, specified as a 2-tuple vector in Hz, kHz, MHz, or GHz. This option is not available for bandstop filters.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev and Filter type to Bandpass.

`Passband attenuation (dB)` — Passband attenuation
`10*log10(2)` (default) | scalar

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

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev.

`Stopband frequencies` — Stopband frequencies for bandstop filters
`[2.1 2.9] GHz` (default) | 2-tuple vector

Stopband frequencies for bandstop filters, specified as a 2-tuple vector in Hz, kHz, MHz, or GHz. This option is not available for bandpass filters.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev and Filter type to Bandstop.

`Stopband attenuation (dB)` — Stopband attenuation
`40` (default) | scalar

Stopband attenuation, specified as a scalar dB. For bandstop filters, this value is applied equally to both edges of the stopband.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev and Filter type to Bandstop.

`Source impedance (Ohm)` — Input source resistance
`50` (default) | scalar

Input source resistance, specified as a scalar in ohms.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev.

`Load impedance (Ohm)` — Output load resistance
`50` (default) | scalar

Output load resistance, specified as a scalar in ohms.

Dependencies

To enable this parameter, set Design method to Butterworth or Chebyshev.

`Ground and hide negative terminals` — Ground RF circuit terminals
`on` (default) | `off`

Select to internally ground and hide the negative terminals. Clear to expose the negative terminals. When the terminals are exposed, you can connect them to other parts of your model.

`Export` — Save filter design to a file
button (default)

Use this button to save filter design to a file. Valid file types are .mat and .txt.

Visualization

`Parameter 1` — Type of plots on y-axis
`Voltage transfer` (default) | `Phase delay` | `Group delay`

Type of plots, specified as Voltage transfer, Phase delay, or Group delay.

`Parameter 2` — Type of plots
`None` (default) | `Voltage transfer` | `Phase delay` | `Group delay`

Type of plots, specified as None, Voltage transfer, Phase delay, or Group delay.

`Format 1` — Scaling of y-axis
`Magnitude (decibels)` (default) | `Magnitude (linear)` | `Angle (degrees)` | `Real` | `Imaginary`

Scaling of y-axis, specified as,

Magnitude(decibels), Magnitude(linear) or Angle(degrees), Real, or Imaginary for Voltage transfer parameters.
Magnitude(decibels) or Magnitude(linear) for Phase delay or Group delay parameters.

`Format 2` — Scaling of y-axis
`Magnitude (decibels)` (default) | `Magnitude (linear)` | `Angle (degrees)` | `Real` | `Imaginary`

Scaling of y-axis, specified as,

Magnitude(decibels), Magnitude(linear) or Angle(degrees), Real, or Imaginary for Voltage transfer parameters.
Magnitude(decibels) or Magnitude(linear) for Phase delay or Group delay parameters.

`Frequency points` — Frequency points to plot on x-axis
`logspace(0,10,101) Hz` (default) | vector

Frequency points to plot on x-axis, specified as a vector with each element units in Hz, kHz, MHz, or GHz.

`X-axis scale` — X-axis scale
`Linear` (default) | `Logarithmic`

X-axis scale, specified as Linear or Logarithmic.

`Y-axis scale` — Y-axis scale
`Linear` (default) | `Logarithmic`

Y-axis scale, specified as Linear or Logarithmic.

Model Examples

Frequency Response of Lowpass Chebyshev Filter

Example for Filter; lowpass Chebyshev

More About

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Frequency Responses

Filter Type	Frequency Response
Lowpass
Highpass
Bandpass
Bandstop

Frequency response of typical lowpass even and odd order Chebyshev filters:

Frequency response of typical inverse low pass even and odd order Chebyshev filters:

Parameters To Define Filter and Design Tips

This table shows all the parameters required to design each filter correctly:

Additional Design Tips

Some additional design tips:

References

[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.

Documentation

Filter

Description

Parameters

Main

Design method — Simulation type Butterworth (default) | Chebyshev | Inverse Chebyshev | Ideal

Filter type — Filter type Lowpass (default) | Highpass | Bandpass | Bandstop

Implementation — Implementation LC Tee | LC Pi | Transfer function | Constant per carrier | Frequency Domain

Passband edge frequency — Passband edge frequency 1 GHz (default) | scalar

Dependencies

Implement using filter order — Implement using filter order off (default) | on

Dependencies

Filter order — Filter order 3 (default) | scalar

Dependencies

Passband frequency — Passband frequency for lowpass and highpass filters scalar

Dependencies

Passband frequencies — Passband frequencies for bandpass filters [2 3] GHz (default) | 2-tuple vector

Dependencies

Passband attenuation (dB) — Passband attenuation 10*log10(2) (default) | scalar

Dependencies

Stopband frequencies — Stopband frequencies for bandstop filters [2.1 2.9] GHz (default) | 2-tuple vector

Dependencies

Stopband attenuation (dB) — Stopband attenuation 40 (default) | scalar

Dependencies

Source impedance (Ohm) — Input source resistance 50 (default) | scalar

Dependencies

Load impedance (Ohm) — Output load resistance 50 (default) | scalar

Dependencies

Ground and hide negative terminals — Ground RF circuit terminals on (default) | off

Export — Save filter design to a file button (default)

Visualization

Parameter 1 — Type of plots on y-axis Voltage transfer (default) | Phase delay | Group delay

Parameter 2 — Type of plots None (default) | Voltage transfer | Phase delay | Group delay

Format 1 — Scaling of y-axis Magnitude (decibels) (default) | Magnitude (linear) | Angle (degrees) | Real | Imaginary

Format 2 — Scaling of y-axis Magnitude (decibels) (default) | Magnitude (linear) | Angle (degrees) | Real | Imaginary

Frequency points — Frequency points to plot on x-axis logspace(0,10,101) Hz (default) | vector

X-axis scale — X-axis scale Linear (default) | Logarithmic

Y-axis scale — Y-axis scale Linear (default) | Logarithmic

Model Examples

Frequency Response of Lowpass Chebyshev Filter

More About

Frequency Responses

Parameters To Define Filter and Design Tips

Additional Design Tips

References

See Also

RF Blockset Documentation

Support

`Design method` — Simulation type
`Butterworth` (default) | `Chebyshev` | `Inverse Chebyshev` | `Ideal`

`Filter type` — Filter type
`Lowpass` (default) | `Highpass` | `Bandpass` | `Bandstop`

`Implementation` — Implementation
`LC Tee` | `LC Pi` | `Transfer function` | `Constant per carrier` | `Frequency Domain`

`Passband edge frequency` — Passband edge frequency
`1 GHz` (default) | scalar

`Implement using filter order` — Implement using filter order
`off` (default) | `on`

`Filter order` — Filter order
`3` (default) | scalar

`Passband frequency` — Passband frequency for lowpass and highpass filters
scalar

`Passband frequencies` — Passband frequencies for bandpass filters
`[2 3] GHz` (default) | 2-tuple vector

`Passband attenuation (dB)` — Passband attenuation
`10*log10(2)` (default) | scalar

`Stopband frequencies` — Stopband frequencies for bandstop filters
`[2.1 2.9] GHz` (default) | 2-tuple vector

`Stopband attenuation (dB)` — Stopband attenuation
`40` (default) | scalar

`Source impedance (Ohm)` — Input source resistance
`50` (default) | scalar

`Load impedance (Ohm)` — Output load resistance
`50` (default) | scalar

`Ground and hide negative terminals` — Ground RF circuit terminals
`on` (default) | `off`

`Export` — Save filter design to a file
button (default)

`Parameter 1` — Type of plots on y-axis
`Voltage transfer` (default) | `Phase delay` | `Group delay`

`Parameter 2` — Type of plots
`None` (default) | `Voltage transfer` | `Phase delay` | `Group delay`

`Format 1` — Scaling of y-axis
`Magnitude (decibels)` (default) | `Magnitude (linear)` | `Angle (degrees)` | `Real` | `Imaginary`

`Format 2` — Scaling of y-axis
`Magnitude (decibels)` (default) | `Magnitude (linear)` | `Angle (degrees)` | `Real` | `Imaginary`

`Frequency points` — Frequency points to plot on x-axis
`logspace(0,10,101) Hz` (default) | vector

`X-axis scale` — X-axis scale
`Linear` (default) | `Logarithmic`

`Y-axis scale` — Y-axis scale
`Linear` (default) | `Logarithmic`