Filter
Filter complex RF broadband signals.
blockType: Filter
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Path in the library: |
Description
Block Filter It is a filter of complex radio frequency (RF) broadband signals. To design a filter, you can use the Butterworth, Chebyshev methods, or the Chebyshev inverse method. You can also simulate a filter in the time or frequency domain and plot its characteristics.
Ports
Input
#
IN
—
time-dependent input signal
real scalar | real column | complex scalar | complex column
Details
A time-dependent input signal specified as a real scalar or column, complex scalar or column. The column represents consecutive points in time.
| Data types |
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| Complex numbers support |
Yes |
Output
#
OUT
—
time-dependent output signal
complex scalar | complex column
Details
A time-dependent output signal returned as a complex scalar or column. The time-dependent output signal is equal in size to the time-dependent input signal.
| Data types |
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| Complex numbers support |
Yes |
Parameters
Main
#
Design method —
filter design method
Butterworth | Chebyshev | InverseChebyshev
Details
The filter construction method. Set as:
-
Butterworth -
Chebyshev -
InverseChebyshev
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Filter type —
filter response type
Lowpass | Highpass | Bandpass | Bandstop
Details
The type of filter response. Set as:
-
Lowpass– simulates the type of low-pass filter with the design specified in Design method. -
Highpass– simulates the type of high-pass filter with the method specified in Design method. -
Bandpass– simulates the type of bandpass filter with the method specified in Design method. -
Bandstop– simulates the type of bandpass filter with the method specified in Design method.
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Implement using filter order —
enable the implementation using the filter order
Logical
Details
Check this box to implement the filter order manually.
| Default value |
|
| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Filter order —
filter order
Real number
Details
The filter order, set as an integer, . If for Filter type value selected Lowpass or Highpass, specify the number of single storage items. If for the parameter Filter type value selected Bandpass or Bandstop, specify twice as many elements.
Dependencies
To use this option, check the option box. Implement using filter order.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Passband frequency (Hz) —
bandwidth frequency
Real number
Details
The bandwidth frequency for low-pass, high-pass, and bandpass filters, specified as a positive real scalar or a positive ascending vector of two values. Depending on the filter type, the accepted value types and default values vary.:
| Parameter value Filter type | Value type | Default values (Hz) |
|---|---|---|
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Positive real scalar |
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Positive real scalar |
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A positive increasing vector of two values |
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Dependencies
To use this parameter, set for the parameter Filter type meaning Lowpass, Highpass or Bandpass.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Passband frequency (Hz) —
the description is missing
Real number
Details
The description is missing.
| Default value |
|
| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
# Passband frequencies (Hz) — the description is missing
Details
The description is missing.
| Default value |
|
| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
# Passband frequencies (Hz) — bandwidth attenuation
Details
The attenuation of the filter bandwidth, specified as a positive real scalar. For bandpass filters, this value is applied equally to both edges of the bandwidth.
Dependencies
To use this parameter, set for the parameter Filter type meaning Lowpass, Highpass or Bandpass.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Passband attenuation (dB) —
bandwidth frequencies for bandpass filters
Real number
Details
Bandwidth frequencies for bandpass filters, specified as a positive real scalar or a positive increasing vector of two values. Depending on the parameters Filter type and Implement using filter order The accepted value types and default values differ as follows.
| Parameter value Filter type | Value type | Default values (Hz) | To enable this option |
|---|---|---|---|
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Positive real scalar |
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Install for Filter type meaning |
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Positive real scalar |
|
Install for Filter type meaning |
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A positive increasing vector of two values |
|
Install for Filter type meaning |
|
A positive increasing vector of two values |
|
Install for Filter type meaning |
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Stopband frequency (Hz) —
delay band frequencies for bandpass filters
Real number
Details
The frequencies of the delay band for bandpass filters, specified as a positive real scalar or a positive increasing vector of two values, in Hz.
In the parameters Filter type and Implement using filter order The accepted value types and default values differ as follows.
| Parameter value Filter type | Value type | Default values (Hz) | To enable this option |
|---|---|---|---|
|
Positive real scalar |
|
Install for Filter type meaning |
|
Positive real scalar |
|
Install for Filter type meaning |
|
A positive increasing vector of two values |
|
Install for Filter type meaning |
|
A positive increasing vector of two values |
|
Install for Filter type meaning |
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Stopband frequency (Hz) —
the description is missing
Real number
Details
The description is missing.
| Default value |
|
| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
# Stopband frequencies (Hz) — the description is missing
Details
The description is missing.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
# Stopband frequencies (Hz) — the description is missing
Details
The description is missing.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
Stopband attenuation (dB) —
attenuation in the delay band
Real number
Details
The attenuation in the delay band, specified as a positive real scalar greater than the value of the parameter Passband attenuation (dB), in dB.
Dependencies
To use this parameter:
-
Set for the parameter Filter type meaning
Lowpass,HighpassorBandpassand uncheck the box Implement using filter order. -
Install Filter type meaning `Bandstop`and check the box Implement using filter order.
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
#
RF frequency (Hz) —
the center of the frequency band of the signal
Real number
Details
The center of the frequency band of the signal relative to the transfer function of the filter is given as a positive real scalar, in Hz.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
Main
#
Modeling domain —
the field of modeling
Time (Fixed step) | Frequency (Digital filter)
Details
The field of modeling. Set as:
-
Time (Fixed step)– simulation using fixed-step solvers (NDF2,Trapezoidal,Backward Euler) -
Frequency (Digital filter)– simulation using a 1-D digital filter.
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
Solver —
time domain solvers
NDF2 | Trapezoidal | Backward Euler
Details
Fixed-step solvers. Set as:
-
NDF2– a balance of narrowband and broadband accuracy. This solver is suitable for situations where the frequency content of the signals in the system is unknown relative to the Nyquist frequency. -
Trapezoidal– performs narrow-band modeling. The frequency distortion and lack of damping effect make this method unsuitable for most broadband simulations. -
Backward Euler– modeling of the largest class of systems and signals. The damping effects make this solver suitable for broadband modeling, but the overall accuracy is low.
| Values |
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| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
No |
#
FIR filter length —
Length of 1-D digital filter
Real number
Details
The length of a 1-D digital filter or the pulse response duration, set as a positive integer.
Dependencies
To use this parameter, set for the parameter Modeling domain meaning Frequency (Digital filter).
| Default value |
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| Program usage name |
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| Tunable |
No |
| Evaluatable |
Yes |
Additional information
Algorithms
Determination of FIR filter coefficients
The program calculates the coefficients of a discrete FIR filter using the parameters RF frequency (Hz) and FIR filter length, as well as the transfer function specified using the obtained poles and zeros of the filter.
To determine the coefficients of the direct form of the Discrete FIR Filter block, the following steps are performed:
-
Determines the frequency points located in the bandwidth centered around the carrier frequency using this formula.
Where
-
– carrier frequency, in Hz.
-
– the length of the FIR filter.
-
– time step of the filter.
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Determines the values of the transfer functions for the frequency points specified in step 1 using this formula.
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Determines the coefficients of a discrete FIR filter using this formula