In article j5M_b.5335$AL.133044@attbi_s03, Harold E. Johnson
writes


What's a "hound dog crystal"?

How to deal with butlers:
http://etext.library.adelaide.edu.au...chapter41.html


Best regards,
Spehro Pefhany



Thanks Spehro. Delightful! I wondered what it had to do with things until
down the page a bit.

Sorry for the lack of definition, I was referring to crystals not
specifically treated to enhance overtone operation. When a manufacturer
makes a crystal for overtone use, he/she treats it to suppress spurious
responses close by the desired overtone so the crystal "likes" to
operate
properly. An untreated crystal often will have those responses and
oscillate
on one or more of them instead of the desired frequency unless the
feedback
and tuned circuit are carefully managed to ignore them. The higher
impedance of Stephensens schematic make that a bit easier to do.


The special techniques were as follows:
Optimise the plating thickness for the overtone and also the electrode
diameter.
Shear mode crystals have a controlled relationship between the resonant
frequency under the electrode and the frequency away from the
electroded region.

Also higher overtones are better polished and more sensitive to
parallelism.

Overtones pull less approx pulling of fundimental/overtone number
squared.



--
ddwyer