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#Post#: 92--------------------------------------------------
10 MHz Crystal Model
DIR By: Robert
Date: March 17, 2025, 7:17 pm
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Based on the well known equivalent circuit of a quartz crystal,
I am missing the typical series AND parallel resonances in the
simulation for a 10 MHz crystal. Please change the extension of
the file in the attachment from txt to cir.
Any comments are welcome.
Robert
#Post#: 93--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: MC12
Date: March 19, 2025, 3:30 am
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Does this help?:
HTML https://www.electronics-tutorials.ws/oscillator/crystal.html
#Post#: 94--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: Robert
Date: March 19, 2025, 8:02 am
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I am missing the pronounced series and parallel resonances in
the simulation.
Other than that I am familiar with quartz crystal oscillators,
etc.
Thanks for the link.
Robert
#Post#: 95--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: MC12
Date: March 19, 2025, 1:37 pm
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I'm not in a position to run MC12 at the moment, it would help
if you posted images of your actual circuit and simulation
results.
#Post#: 96--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: Robert
Date: March 19, 2025, 2:35 pm
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I attached 2 screenshots.
#Post#: 97--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: MC12
Date: March 19, 2025, 3:22 pm
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I don't understand. On the first step, when R4 = R2, why
doesn't the pale blue plot match the red plot?
It seems to me X1 is doing what it is supposed to do, but X2
isn't. Have you modified X2?
#Post#: 98--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: Robert
Date: March 19, 2025, 6:20 pm
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I did not modify X2. That's what bugging me too.
For the case R2 = R4 = 50 Ohm, the plots should be the same.
When I disable the stepping, the two plots (red and green) are
identical.
Also, when I have only X2 displayed with stepping, the curve for
R4 = 50 Ohm is the same as though it would be the circuit with
X1.
In other words, for the case when R2 = R4 = 50 Ohm, the plots
coinside, but only the green curve is visible (with stepping).
All in al,l I think there is no real issue with the simulation.
Thank you for dealing with my posting.
Regards,
Robert
P.S.: I wish there would be a macro showing the components (with
values) of the crystal equivalent circuit.
#Post#: 99--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: MC12
Date: March 19, 2025, 7:59 pm
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Without an explanation for this behaviour, it seems to be a bug.
#Post#: 100--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: MC12
Date: March 20, 2025, 6:39 am
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What if you actually insert the equivalent network?
#Post#: 101--------------------------------------------------
Re: 10 MHz Crystal Model
DIR By: Robert
Date: March 20, 2025, 8:47 am
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I don't know the equivalent network.
As I mentioned in my previous post:
"P.S.: I wish there would be a macro showing the components
(with values) of the crystal equivalent circuit."
What I would need is: Ls, Cs, Rs and Cp of the crystal.
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