[time-nuts] Crystal from Morion MV89A measured

[Gerhard Hoffmann]

I recently have dissected a defective Morion MV89A oven. Since it is 
hard to get
SC crystals in small amounts, this might be interesting for experimenters.
There are many defective Morions from China.
I have checked the crystal parameters at room temperature
and at the intended temperature.


nominal at room temp.

F = 4999868.18548896
Q = 2058123.87937723
L = 5.31149294399851
C = 1.90768447144417E-16
R = 81.074358418583
C0= 2.8136087840004E-12


B-Mode at room temperature / 27°C

F = 5456268.74855202
Q = 2070228.75819907
L = 5.60406600257822
C = 1.51825777903696E-16
R = 92.8026816958027
C0= 2.50200142407676E-12

fundamental at room temp.

F = 1706530.674
Q =12634
L = 2.882184522
C = 3.017798817E-15
R = 2446.1
C0= 3.400172339E-12




Nominal frequency at 87.8°C

F = 4999977.73472294
Q = 2210624.24356611
L = 5.31056260615351
C = 1.90793506338953E-16
R = 75.4698598161708
C0= 2.67067707950378E-12


B-Mode at 88°C

F = 5445966.6930594
Q = 1559143.3579169
L = 4.56636349264629
C = 1.87033681366853E-16
R = 100.216511187362
C0= 3.02668789364201E-12


Fundamental @ 88°c

F = 1706366.18003318
Q = 7829.11559388434
L = 2.67725816365808
C = 3.24941770179082E-15
R = 3666.31393448872
C0= 3.28464263904697E-12


The fundamental is so weak that it does not deserve a trap. The B-mode
resonance at +9.5% is nearly as good as the nominal frequency. One might
experience frequency hopping if this is not taken care of.

The 88°C was produced with a Steinelt heat gun that was sitting on the
boom of the microscope. I wonder why my low cost DG8SAQ VNWA can
measure this just easily and my R&S ZVB cannot. Simply plug the xtal on 
port 1.
The reference frequency of the VNWA was locked to my LUCENT GPS source.

There are some spurii above the nominal frequency and above the b-mode.
I did not check them in detail. The time for a sweep is half an hour because
of the required settling time and the huge number of measurement points.
And it takes a lot of sweeps until one is on the right spot.
I you zoom in, the spurii look deeper. The 2 attached plots show some 
ringing after
excitation of the resonance, they are taken too fast. They create 
nonphysical results
because it seems that more energy comes back than is sent by the VNA but
it is only energy stored in the crystal.
That does not matter here because I used these plots only for locating the
resonances and not for the crystal estimator.
The Auswahl_005.png plot has some of the experimenting history.

Cheers,

Gerhard


-------------- next part --------------
A non-text attachment was scrubbed...
Name: spurii_above_nominal.png
Type: image/png
Size: 50647 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20200605/4b4041ec/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Spurii_around_bmode.png
Type: image/png
Size: 50737 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20200605/4b4041ec/attachment-0001.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: VNWA setup.png
Type: image/png
Size: 607429 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20200605/4b4041ec/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Auswahl_005.png
Type: image/png
Size: 118475 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20200605/4b4041ec/attachment-0003.png>