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Feb 20th, 2020, 9:22pm
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Squelching a crystal filter (Read 592 times)
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Squelching a crystal filter
Dec 01st, 2017, 8:36am
I am looking to receive pulsed signals through a narrow crystal filter.
The filter design itself is relatively easy, and I have a design that gives me the bandwidth I need, but when the pulse stops, the filter rings for a relatively long time.

I am experimenting in LTSpice but I wonder if there is maybe already work done on "squelching" a filter using FETs or analog switches to stop the crystals.  Seems like something radar designers might have done.

I know how long the pulse will be, so I can squelch the filter at the appropriate moment, and then release it to be ready for the next pulse.

My test filter uses 3.579 MHz crystals that I have very good data on, and the spice predictions for the basic filter are tracking nicely with the real hardware.

I'm wondering if anyone here knows of implementations like this that I could look at.
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