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Crystal Filter Simulation #ubitx #filters

Jonathan Kayne, KM4CFT
 

Hi all,
I am in the process of trying to run some LTspice simulations of the crystal filters.
I am aware that one can model a quartz crystal using a series combination of a resistor, inductor and capacitor all in parallel with another capacitor. 
What I want to know is if there is a way to find out the motion parameters of a crystal given a datasheet, or if there is a set of "typical" values I can use. 
Please keep in mind that this is a simulation, and I am not looking for an exact replica. (I expect the values to be different from what is measured)

The point of this is purely for educational purposes, as I want to learn about how these filters work and how to possibly design them in the future.

73,
-Jonathan, KM4CFT

Curt
 

Jonathan

I appreciate your interest.  Start with this article, let me know if you have any issues getting it --

https://www.arrl.org/files/file/QEX_Next_Issue/Nov-Dec_2009/QEX_Nov-Dec_09_Feature.pdf

These parameters typically are not listed on a datasheet.  The article describes a 4915 kHz crystal - widely used by hams to build CW narrow filters.  Also in some designs varactors are placed between the crystals to allow variable bandwidth, but a caution this also moves the center frequency (so a receiver may use an oscillator after the crystal filter to compensate for this - the K2 does this). 

in practice these parameters have to be measured - and some hams have made simple test equipment to make these measurements - or maybe suitable gear maybe there at your university. 

my email is listed at qrz.com.  glad to dialog further - and maybe I can help you with some crystals for your project.  I can also share that I once worked with some specialists who learned to make these things - they are called bulk acoustic wave - onto a chip - they are inside your cell phone!  I can share other info via email. 

73 Curt wb8yyy