Chebyshev1FilterModel
creates a lowpass Chebyshev type 1 filter of order n.
Chebyshev1FilterModel[{n,ωc}]
uses the cutoff frequency ωc.
Chebyshev1FilterModel[{"type",spec}]
creates a filter of a given "type" using the specified parameters spec.
Chebyshev1FilterModel[{"type",spec},var]
expresses the model in terms of the variable var.
Details
- Chebyshev1FilterModel returns the filter as a TransferFunctionModel.
- Chebyshev1FilterModel[{n,ω}] returns a lowpass filter with attenuation of (approximately 3 dB) at frequency ω.
- Chebyshev1FilterModel[n] uses the cutoff frequency of 1.
- Lowpass filter specification {"type",spec} can be any of the following:
-
{"Lowpass",n} lowpass filter of order n and cutoff frequency 1 {"Lowpass",n,ωp} use cutoff frequency ωp {"Lowpass",{ωp,ωs},{ap,as}} use full filter specification giving passband and stopband frequencies and attenuations - Highpass filter specifications:
-
{"Highpass",n} highpass filter with cutoff frequency 1 {"Highpass",n,ωp} use cutoff frequency ωp {"Highpass",{ωs,ωp},{as,ap}} full filter specification - Bandpass filter specifications:
-
{"Bandpass",n,{ωp1,ωp2}} bandpass filter with passband frequencies ωp1 and ωp2 {"Bandpass",n,{{ω,q}}} use center frequency ω and quality factor q {"Bandpass",{ωs1,ωp1,ωp2,ωs2},{as,ap}} full filter specification - Bandstop filter specifications:
-
{"Bandstop",n,{ωp1,ωp2}} bandstop filter with passband frequencies ωp1 and ωp2 {"Bandstop",n,{{ω,q}}} use center frequency ω and quality factor q {"Bandstop",{ωp1,ωs1,ωs2,ωp2},{ap,as}} full filter specification - Frequency values should be given in an ascending order.
- Values ap and as are respectively absolute values of passband and stopband attenuations.
- Given a gain fraction , the attenuation is .
- The quality factor q is defined as , with ω being the center frequency of a bandpass or bandstop filter. Higher values of q give narrower filters.
Examples
open allclose allBasic Examples (2)
Scope (8)
Create a symbolic Chebyshev type 1 filter model:
Exact computation of the model:
Computation of the model with precision 24:
Create a filter model using the variable s:
Create a lowpass Chebyshev type 1 filter model with a cutoff frequency of 10:
Create a lowpass Chebyshev type 1 filter using the full specification:
Create a highpass Chebyshev type 1 filter:
Create a bandpass filter with passband frequencies 1 and 10 and attenuation of order 3:
Use center frequency 1 and quality factor 1/3:
Create a bandpass Chebyshev type 1 filter using the full specification:
Applications (6)
Create a lowpass Chebyshev type 1 filter:
Filter out high-frequency noise from a sinusoidal signal:
Chebyshev type 1 filter phase shifts the response by Arg[tf[ω ]], where ω is the frequency of the input sinusoid:
Create a highpass Chebyshev type 1 filter from the lowpass prototype:
Filter out low-frequency sinusoid from the input:
Design a digital FIR lowpass filter using the Chebyshev 1 approximation that satisfies the following passband and stopband frequencies and attenuations:
Obtain the equivalent analog frequencies assuming a sampling period of 1:
Compute the analog Chebyshev 1 transfer function:
Convert to discrete-time model:
Create an FIR approximation of a discrete-time Chebyshev 1 IIR filter.
Implement a lowpass digital Chebyshev type 1 filter:
Obtain the desired number of FIR samples from the impulse response of the discrete-time Chebyshev filter:
Smooth financial data using an FIR approximation of a Chebyshev filter:
Filter an image using a discrete-time lowpass Chebyshev type 1 filter:
Properties & Relations (8)
Stopband attenuation increases as order n increases:
Passband width of "Bandpass" filter decreases with increasing quality factor q:
Phase response of a third-order "Lowpass" type 1 Chebyshev filter:
Compare phase responses for different filter orders:
Phase response of a "Bandpass" filter for several quality factors:
Compare Chebyshev type 1 and type 2 lowpass filters:
Extract the order of the Chebyshev type 1 polynomial:
Find the poles of a Chebyshev type 1 filter:
Plot poles of the Butterworth filter:
Implement a lowpass digital Chebyshev type 1 filter:
Text
Wolfram Research (2012), Chebyshev1FilterModel, Wolfram Language function, https://reference.wolfram.com/language/ref/Chebyshev1FilterModel.html (updated 2016).
CMS
Wolfram Language. 2012. "Chebyshev1FilterModel." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/Chebyshev1FilterModel.html.
APA
Wolfram Language. (2012). Chebyshev1FilterModel. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Chebyshev1FilterModel.html