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Visualising voltage modulation amplitude vs phase shift between 2 sources

Dear AWR Users,

Can anybody please advise how to visualise correctly the voltage modulation amplitude Vac dependance on the phase shift between 2 AC voltage sources ACVS? I expect to see the periodicity of the resulting Vac signal by sweeping the AC voltage angle of source 1 from 0 to 360 deg (full period). I did the simulations at two AC frequencies 100 and 1000Hz. I would like to understand what is wrong in my measurements. The details of the experiments can be found in the attached project.

Thank you!

Kind regards

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Re: Visualising voltage modulation amplitude vs phase shift between 2 sources

Hello,

   I took a quick look at your project and I have some suggestions you can try.

1.  Don't place ports at your ACVS sources.  This is equivalent to putting a 50 ohm resistor to ground right at your source.

2.  For the sweep, don't see the sweep units, that will just confuse things. 

3.  I would first plot the Vtime measurement at the two sources and then at the output port.   This will get a feel for the waveforms.   When they are 180 degrees out of phase, the output voltage should be 0 since they will be cancelling each other out.   

4.  Once you are comfortable with the Vtime measurements, you the can use Vcomp measurement to measure tone 1 at the port for magnitude or phase.  This will give you the magnitude and phase of the fundamental harmonic of the output signal (since the network is linear, there will only be signals in the fundamental).   I am mostly sure the Vac measurements will do the same thing but you really don't need to use AC analysis since you are using a linear network. 

Anyway, I hope these get you moving along. 

AWR Support.

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Re: Visualising voltage modulation amplitude vs phase shift between 2 sources

Hello,

Thank you for your detailed explanation!

I realized myself that the main problem was the units of the Angle sweep. You are right that I should not select the "Degree". Although I was able to measure the effect of the phase difference between my ACVS sources on the voltage of the output port using AC analysis, thanks to your reply I have learned now how to do it using non-linear measurementsSmiley Wink And how to select different harmonics (tones) for example. You are also right that the measurements for Vac (using APLAC AC simulator) and Vcomp (using APLAC HB simulator) at the output port are identical!

I have a general question on understanding the difference between the simulators. Would you be so kind to explain why the Im and Re components of the complex Voltage signal obtained with the different simulators (in my case APLAC AC vs APLAC HB) look different whilst the magnitude (modulus) of the Voltage is the same and Phase of the Voltage signal is just shifted by the constant on the Y-axis?

Best regards

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Re: Visualising voltage modulation amplitude vs phase shift between 2 sources

If you compare the output phase to the input phase (or phase of the gain Vout/Vin), the phase change is identical from all simulators.  HB stimuli and measurements are generally cosine based.  However, in order to match transient/SPICE simulation, the sources for nonlinear analysis need to be sine based.  The sources are all shifted by 90deg so that the output voltage will look the same from HB and transient/SPICE simulations at steady state.

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