"The correct method to determine crystal
      cut is a spectrum analyzer with tracking
      generator"

There are app notes out there showing the use of a small
fixture, a vector voltmeter and signal generator.

With a proper jig (fixture) a particular crystal's *full*
characteristics may be measured.

A spectrum analuzer and tracking gen will fail to
accurately show/allow the accurate mesurement of some
important parameters ... parameters requiring the
knowledge of *the phase change* versus frequency as
the crystal is tuned though resonance thereby requiring
the use of a phase (and not just amplitude) measuring
device such as a vector voltmeter or vector network
analyzer.

Jim



----- Original Message -----
From: "Peter L. Peres" <plp@ACTCOM.CO.IL>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, June 15, 2002 2:43 AM
Subject: Re: [PIC]: Will an unprogrammed chip oscillate?


> On Fri, 14 Jun 2002, Lawrence Lile wrote:
>
> >Series cut .. Parallel cut - How does one figure out which applies to the
> >crystal in question.  I just looked at EVERY crystal in Digikey, and NONE
> >(i.e. diddlysquat, Nada, Nichts, Nyet, Zip, Zilcho) specify whether the
> >crystal is parallel or serial cut.  Now there are a few that allude to
> >"When run in parallel mode.."  "Effective series resistance"  And one has
a
> >whole paragraph of rubber language which basically says "Your Mileage May
> >Vary" when run in parallel or series mode, but none of them just come
right
> >out and say one or the other.
> >
> >I guess the correct method is to use a CRYSTAL ball.  <Groan>
>
> Last time I checked Mouser specified both cut and required capacitance.
>
> The correct method to determine crystal cut is a spectrum analyzer with
> tracking generator (or a noise box) which will tell you what you want to
> know immediately. You can substitute a VXO for the specan using the same
> crystal (buy two) and a RF signal meter. When you use the VXO the second
> crystal will be between it and the signal meter. You will have one peak
> and one trough. The peak is the serial f. and the trough the parallel f.
> Make sure that the reactive crystal load does not pull the VXO (use a
> buffer). A counter will tell you exactly where you are. Note that you are
> doing exactly what the specan is doing. Some grid dip meters will work as
> VXO if you fit a crystal. Mine does not ...
>
> hope this helps,
>
> Peter
>

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