Transfer function in a circuit in Simulink?

Hey guys. I have simulated a simple filter and I want to see the transfer function graph (bode plot) of it and I can't use the transfer function. I thought that the wise thing to do would be to use the "PS Divide" block and divide the output and input voltages of the circuit, but that didn't work. Could anyone tell me what I need to do?

This is what I tried:

http://i1226.photobucket.com/albums/ee410/jean28x/bode1.jpg

This is the graph I got (obviously wrong):

http://i1226.photobucket.com/albums/ee410/jean28x/bode2.jpg

Answer 1

[Cedrik]

It look like the voltage you are measuring is about the same, so the ratio is around 0 (with the scale on the y-axis, it is tough to say).

The other aspect is: you are looking at a time domain signal while the bode plot "is a graph of the transfer function of a linear, time-invariant system versus frequency, plotted with a log-frequency axis, to show the system's frequency response[1]." You have to process the signal to obtain a Bode Plot.

I would suggest you use a Controlled Voltage Source as input with a S-PS block to convert the input from Simulink into Simscape and than a Voltage Sensor as output with a PS-S block. In the Simulink Control Design Library, you will find the Bode Plot that you are looking for.

[1] http://en.wikipedia.org/wiki/Bode_plot