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Discussion of precise time and frequency measurement

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Re: [time-nuts] FRSC problem

CD
Corby Dawson
Sat, Oct 18, 2008 12:24 AM

Bob,

Use a 50 ohm termination on the counters input and use a 1 second gate
time.

Power up from a cold start (off at least 1/2 hour) and watch the
frequency or the control voltage. The frequency should vary about 50 hz
or more as the control voltage sweeps about 15 volts. As it warms up it
should start sweeping across the center frequency of 10Mhz. If it stops
sweeping after 8 or so minutes it is most likely locking.
Depending on how the lock pin is configured it could be open collector
(useing a DVM on the ohms semiconductor position with the + lead on the
lock pin and the other to ground, will read open until locked and then
read a low value when locked.) or it could be wired to give a TTL level
output when locked. Lamp voltage shopuld be > 8VDC. Hope this helps.

Corby Dawson


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Bob, Use a 50 ohm termination on the counters input and use a 1 second gate time. Power up from a cold start (off at least 1/2 hour) and watch the frequency or the control voltage. The frequency should vary about 50 hz or more as the control voltage sweeps about 15 volts. As it warms up it should start sweeping across the center frequency of 10Mhz. If it stops sweeping after 8 or so minutes it is most likely locking. Depending on how the lock pin is configured it could be open collector (useing a DVM on the ohms semiconductor position with the + lead on the lock pin and the other to ground, will read open until locked and then read a low value when locked.) or it could be wired to give a TTL level output when locked. Lamp voltage shopuld be > 8VDC. Hope this helps. Corby Dawson ____________________________________________________________ Click here for free information on nursing degrees, up to $150/hour http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3nEnlcpvqS5yN8Pn4HQn1rAgSMADmL8Phsl5T7J0H4fUn3TD/