stepresp

Step-signal response for rational object and rationalfit function object

Description

example

[outputsignal,tout] = stepresp(h,ts,n,trise) computes the time domain response of a rational function object, h, to a step signal based on the number of samples, n and the rise time, trise.

Examples

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Calculate the step response of a rational function object from the file passive.s2p. Read passive.s2p.

S = sparameters('passive.s2p');
freq = S.Frequencies;

Get S11 and convert to a TDR transfer function.

s11 = rfparam(S,1,1);
Vin = 1;
tdrfreqdata = Vin*(s11+1)/2;

Fit to a rational function object.

tdrfit = rationalfit(freq,tdrfreqdata);

Define parameters for a step signal. Define parameters for a step signal

Ts = 1.0e-11;
N = 10000;
Trise = 1.0e-10;

Calculate the step response for TDR and plot it

[tdr,t1] = stepresp(tdrfit,Ts,N,Trise);
figure
plot(t1*1e9,tdr)
ylabel('TDR')
xlabel('Time (ns)') Input Arguments

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Rational function object, specified as a rationalfit object handle.

Example:

Data Types: double
Complex Number Support: Yes

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

Example:

Data Types: double

Number of samples, specified as a positive scalar integer.

Example:

Data Types: double

Time taken for step signal to reach maximum value, specified as a positive scalar integer in seconds.

Example:

Data Types: double

Output Arguments

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Output signal,

Example:

Data Types: double
Complex Number Support: Yes

Sample time of the output signal, returned as a positive scalar integer in seconds.

Example:

Data Types: double

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Step Signal Equation

RF Toolbox™ uses the following equation to for the step signal:

$\left\{\begin{array}{l}U\left(k{t}_{s}\right)=k{t}_{s}/{t}_{rise},\\ U\left(k{t}_{s}\right)=1,\end{array}\text{ }\text{ }\begin{array}{c}0\le k<\left({t}_{rise}/{t}_{s}\right)\\ \left({t}_{rise}/{t}_{s}\right)\le k\le N\end{array}$

The following figure illustrates the construction of this signal. 