HP 4192A finding resonance

[Adam_Stouffer]

Hello all. I'm using this attached VI to run frequency sweeps on a HP 4192A imedpance analyzer. What I'm trying to do is have it also display the resonant point of the device being measured. It corresponds to the phase being at 0 or the impedance being the highest. That also means know at what frequency it occurs. All I need is a display that shows when the phase is closest to 0 and what frequency it occured at. Any ideas how to go about this? Thanks for your help.

Adam

[Brian_Beal]

I've never used the 4192A, but have done quite a bit with the 4194A.  You should be able to query these values from the analyzer somehow.  If that is not possible, just use the array min/max function on the impedance array.  This will give you the indices that you need, then just take these values and use them to index the impedance array.  I'm not sure what material you are testing, but resonance usually occurs at minimum impedance.

[Adam_Stouffer]

The array min/max looks like a good starting point. Both graphs show frequency on the X axis but I can't figure out how its generated or calculated. Putting probes on all the lines doesn't turn up anything. Take a look at this sample image. All we really need to know is what frequency that spike occurs at. Maybe theres a VI for something like this?


Adam

[Brian_Beal]

You know the start frequency and the step size.  From the data array, you know how many points there are, and at what frequency the points are(increment whatever the array size is from the start freqency by the step frequency).  You can put this into a for loop to produce an array of the frequencies that is the same size as your impedance array.  Then you can use min/max to find the anti-resonance(high peak) index.  Then select that index from the frequency array to get the actual frequency.