From: Winfield Hill
Subject: Re: Querry, Kick Starting Crystal Oscilator.
Date: 10 Nov 2002 04:47:24 -0800
Organization: Rowland Institute
References: <3DCA905A.59FD928B@mmm.com.DELETETHIS> <3DCC9A71.7DF3C3A9@mfi.net> <3DCE1CDD.544A@Spam.Bots>
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>Winfield Hill wrote:
>> Like most crystals, those have a Q of 60,000 to 90,000 which
>> means they'll take to 2 to 3 seconds to reach 50% of the full
>> oscillation energy. That's the way it goes; the energy cannot
>> simply be kick-started into the crystal.
> One company, Transat Corp., claims to have found a solution to
> the slow response time when measuring low frequency crystals:
> [ snip ]
> "Since the parameter evaluation requires at least two measurements
> at different frequencies, the total measurement time is at least
> 20 seconds. Transat's CNA-LF Network Analyzer is based on
> proprietary transmission method that reduces the total measurement
> time for all crystals in the 25-200kHz range to less then 2
> It would seem in order to measure the motional parameters, the
> crystal must be in motion. But with such high Q, it's difficult to
> see how they can get the crystal to settle in such a short time.
> Any ideas how they manage to do this?
They "told" us, a proprietary transmission method. :-) Some of
the crystal parameters are quickly measured by conventional means.
For the rest, I suppose they could get oscillation started (at a
reduced level), then turn off all crystal drive and measure the