Use PicoScope as a Phase Locked Loop comparator and VCO?

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sheimend
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Joined: Wed Sep 29, 2021 5:53 pm

Use PicoScope as a Phase Locked Loop comparator and VCO?

Post by sheimend »

Is it possible to use a PicoScope to drive a phase locked loop (PLL)? This is probably wishful thinking, but I suppose it doesn't hurt to ask.

In my application, I'm trying to auto-tune to the resonant frequency of an ultrasonic transducer (around 28kHz) as its resonance changes in response to external conditions, like touching another object. I'd love to use the AWG channel of the PicoScope to generate the source signal and a current clamp on an input channel to measure the phase of the transducer.

Comparing those two signals is trivial via a math channel, but the part that I'm hoping to accomplish via scripting is to make the signal generator behave like a VCO and change the output frequency to minimize the phase difference between voltage and current.

Eventually, I'll snap to using an integrated circuit version of all of this, but for benchtop development and exploration, it would be so cool if I could run and monitor this process in PicoScope.

Any chance that my dreams can come true? Thanks in advance!!

Gerry
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Joined: Mon Aug 11, 2014 11:14 am

Re: Use PicoScope as a Phase Locked Loop comparator and VCO?

Post by Gerry »

Hi sheimend,

You could adjust the Signal Frequency based upon your capture data, but the PicoScope would be more like a stepped VCO, as you would have to capture the data, (a time delay of a capture period) establish a USB connection (delay of anywhere between <10ms to 10's of ms) transfer the data to the PC (USB transfer rate for specific PicoScope, for the amount of data to be transferred) perform the Math Channel and adjust the Setup of the SigGen, and finally, restart the Capture, (another USB connection delay).

Regards,

Gerry
Gerry
Technical Specialist

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