[time-nuts] Tracor 527A and 10MHz reference input

David C. Partridge david.partridge at perdrix.co.uk
Sun Jun 25 14:25:14 EDT 2017

Yes, does indeed look like it should be 4K7!

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of David C. Partridge
Sent: 25 June 2017 18:50
To: 'Discussion of precise time and frequency measurement'
Subject: [time-nuts] Tracor 527A and 10MHz reference input

A friend says his Tracor 527A works fine with a 10MHz Ref input even though it doesn't have the divide by 2 circuit from the addendum to the 527E manual applied.

I'm puzzled by this - I can't quite see how the reference input circuit can produce a 5MHz output when fed with 10MHz (unless his reference source has a large 5MHz sub-harmonic).

Am I missing something here?

On a related note, the schematic for the divide by 2 circuit in the front of the 527E manual shows a 4R7 resistor from the base of the 2N3904 to ground - this just feels all wrong!!  Has anyone built this and did they change the resistor to (e.g. 47R or 4K7)?


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