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Dynamic Signal Analyzer

version 1.0 (10.5 KB) by

Frequency response signal analyzer for simulation control loops and dynamic systems



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Frequency response signal analyzer for linear and non-linear control loops and dynamic systems. Simulink model. Sine sweep based similar to dynamic signal analyzers for physical systems. User specifies: freq limits, freq decrement, averages, phase criteria for moving to next frequency, start time, input amplitude. Output variable, freq_resp, with freq(rad/sec), closed loop magn, closed loop phase, open loop magn, open loop phase, time at each frequency. Performs 1/(T^-1 - 1) to convert closed loop Transfer function to open loop.

Comments and Ratings (6)

Jim Royalty

Dear Chang,
You are correct. With such a wide error bound (x57.3 too high) for moving to the next frequency excitation, I still never saw an issue. Now I ask, with the correction (lowering the error bound by 57.3), will the next frequency in the sine sweep ever be invoked? Eventually I will be able to answer this.

Chang Duan

Hi, Jim,

    This is a useful tool. I got one question about the phase stable criterior though. Shouldn't the output from atan2 function has the unit of radians? However it is compared with the user input which is in degrees.


Jim Royalty

The design as it is only allows decrementing the excitation frequency. You may update the model and resubmit it. Best regards,


Hi Jim - this simulink block is extrememly useful to my system analysis. It would be useful to me to start the system at a lower frequency, and then increase to a high frequency. I realize that this cannot be done with this block? Is there a way that I achieve this?

Karthik ST

There are errors in frequency saturation block.
and by the way how do take output from this mdl???!!!!

Erdal Bizkevelci

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MATLAB 7 (R14)

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