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timeresp

Time response for rational function object

Syntax

[y,t] = timeresp(h,u,ts)

Description

[y,t] = timeresp(h,u,ts) computes the output signal, y, that the rational function object, h, produces in response to the given input signal, u.

The input h is the handle of a rational function object returned by rationalfit. ts is a positive scalar value that specifies the sample time of the input signal.

The output y is the output signal. RF Toolbox™ software computes the value of the signal at the time samples in the vector t using the following equation.

Y(n)=sum(C.*X(nDelay/ts))+D*U(nDelay/ts)

where

X(n+1)=F*X(n)+G*U(n)X(1)=0F=exp(A*ts)G=(F1)./A

and A, C, D, and Delay are properties of the rational function object, h.

Examples

The following example shows you how to compute the time response of the data stored in the file default.s2p by fitting a rational function object to the data and using the timeresp method to compute the time response of the object.

% Define the input signal
SampleTime = 2e-11;
OverSamplingFactor = 25;
TotalSampleNumber = 2^12;
InputTime = double((1:TotalSampleNumber)')*SampleTime;
InputSignal = sign(randn(1, ...
              ceil(TotalSampleNumber/OverSamplingFactor)));
InputSignal = repmat(InputSignal, [OverSamplingFactor, 1]);
InputSignal = InputSignal(:);

% Create a rational function object
orig_data=read(rfdata.data,'default.s2p');
freq=orig_data.Freq;
data=orig_data.S_Parameters(2,1,:);
fit_data=rationalfit(freq,data);

% Compute the time response
[y,t]=timeresp(fit_data,InputSignal,SampleTime);

Introduced in R2007a

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