timeresp

Time response for rational object and rationalfit 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.

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

where

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

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

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);