Frequency magnitude. CD Bode. State Space

[MSQ]

Hello everyone,

Kindly, I have a simple model that gives me a Bode phase and magnitude, using the block "CD Bode". As i know, this block takes the state space representation and evaluates the frequency and magnitude of the system.

Can I change the value of the Bode Magnitude or Phase? by mean changing the Input signal that bode uses to evaluate the response of the state space ?

Remark: The input I mean here is the value of the sine signal that the Bode uses to give the phase and magnitude of the State Space. 

Thanks

[Barp · Accepted solution]

The CD Bode functions works like a 'sweep' of all frequencies and present that to you. The algorithm is not a controlled frequency, it just give the whole spectrum back. You can't just obtain one specific frequency. however, if you use the fuction "CD Evaluate at Frequency", you can provide the model and the specific frequency and this will give you the specific Mag/Phase for that frequency. This example shows how to perform this operation in LabVIEW:

C:\Program Files (x86)\National Instruments\LabVIEW 2014\examples\Control and Simulation\Control Design\Time Analysis\CDEx Lin Simulation and Steady State.vi

Now, if you want to 'shape' your frequency, then you can create another model, connect them together and try to modify the output frequency. This example shows how to perform this operation:

C:\Program Files (x86)\National Instruments\LabVIEW 2014\examples\Control and Simulation\Control Design\Frequency Analysis\CDEx Frequency Analysis.vi

If you want just to 'simulate' the response of the signal to a specific sinewave, then you need to you another function in the time domain palette called "CD Linear Simulation". With this, you can generate a specific sinewave and you can see its behavior in the time domain. Here is an example:

C:\Program Files (x86)\National Instruments\LabVIEW 2014\examples\Control and Simulation\Control Design\Time Analysis\CDEx Sinewave with Mathscript.vi

Hope this helps,