timeresp

Time response for rational object and rationalfit function object

Syntax

[outputsignal,t] = timeresp(h,inputsignal,ts)

Description

[outputsignal,t] = timeresp(h,inputsignal,ts) computes the output signal that the rational function object produces in response to a give input signal at the specified sample time, ts.

Examples

Time Response

Define the input signal.

SampleTime = 2e-11;
OverSamplingFactor = 25;
TotalSampleNumber = 2^12;
InputSignal = sign(randn(1, ...
              ceil(TotalSampleNumber/OverSamplingFactor)));
InputSignal = repmat(InputSignal, [OverSamplingFactor, 1]);
InputSignal = InputSignal(:);

Create a rational function object.

S = sparameters('default.s2p');
s21 = rfparam(S,2,1);
datafreq = S.Frequencies;
fit_data = rationalfit(datafreq,s21,'Tolerance',-32);

Compute the time response.

[y,t]=timeresp(fit_data,InputSignal,SampleTime);

Input Arguments

inputsignal — Time varying input signal

real finite vector

Time varying input signal, specified as a real finite vector.

Data Types: double

h — Rational function object

rationalfit object

Rational function object, specified as a rationalfit object.

Data Types: double
Complex Number Support: Yes

ts — Sample time of input signal

positive scalar integer

Sample time of the input signal, specified as a positive scalar integer in seconds.

Data Types: double

Output Arguments

outputsignal — Time varying output signal

real finite vector

Time varying output signal, returned as a real finite vector.

Data Types: double

t — Sample time of output signal

nonnegative vector

Sample time of the output signal, returned as a nonnegative vector of time values with discrete step size ts corresponding to the data in outputsignal in seconds.

Data Types: double

More About

Output Signal Equation

timeresp function uses the variant of the following equation to calculate the output signal:

$$Y(n)=sum(C.*X(n-Delay/ts))+D*U(n-Delay/ts)$$

where,

$$\begin{array}{l}X(n+1)=F*X(n)+G*U(n)\\ X(1)=0\\ F=\exp (A*ts)\\ G=(F-1)./A\end{array}$$

A— complex vector of poles of the rational function

C—complex vector of residues of the rational function

D—scalar value specifying direct feedthrough, and

Delay — delay time are properties of the rational function object, h. For more information, see rationalfit function.

Version History

Introduced in R2007a