Author Topic: mistery oscillator  (Read 4639 times)

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Offline geo999Topic starter

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mistery oscillator
« on: February 03, 2015, 08:41:31 pm »
Hello community !

I've just found the oscillator in the picture attached on a pile of junk.

I think it's an oven controlled / temperature controlled oscillator at 26 MHz, not a particularly useful frequency, nonetheless would like to use it ...

Tried to find the specs but looks like "Tele quarz group" doesn't exist anymore ...
Does anyone happen to have some specs / application note / pinout / any info on this part ?

Thanks,
George

 

Offline Alex Eisenhut

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Re: mistery oscillator
« Reply #1 on: February 03, 2015, 09:36:24 pm »
Nope, but I know which is the ground pin... :-DD

(Yeah, I know, don't quit my day job, etc)
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Offline geo999Topic starter

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Re: mistery oscillator
« Reply #2 on: February 03, 2015, 09:39:44 pm »
good one !  :-DD
 


Offline babysitter

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Re: mistery oscillator
« Reply #4 on: February 04, 2015, 06:05:23 am »
What looks like a solder trace between the bottom part and the cap is a solder trace.
[X] You can take it apart, show pics here, learn about it and probably put it together working.
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Offline geo999Topic starter

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Re: mistery oscillator
« Reply #5 on: February 06, 2015, 08:07:48 pm »
Hello,

after some digging I managed to get it running.

The pinout is somehow similar to this one  :  http://www.euroquartz.co.uk/Portals/0/oc31t12a.pdf

Still I do not know what is the purpose for the 3 remaining pins, do I really need to use them ?

The output signal is somehow clipped sine ( please see attached picture )

Does anyone have any idea how to get a clean sine out of this signal ?, use a band pass ( 26 MHz centered ) filter to cut the harmonics ?

Thanks,
George
 

Offline amc184

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Re: mistery oscillator
« Reply #6 on: February 06, 2015, 08:55:56 pm »
Two of those pins are probably for frequency adjustment.  You'd connect one of the 5V pins to one end of a trimmer, ground to the other end and the adjust pin (probably the 2.6V pin) to the wiper.  Adjusting the trimmer will vary the output by a few PPM.

The other 5V pin might be an enable pin with an internal pull up, and might shut off the oven if pulled low.

Just guesses though, you'll have to experiment carefully to find out for sure.
 

Offline jwm_

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Re: mistery oscillator
« Reply #7 on: February 07, 2015, 01:06:22 am »
Does anyone have any idea how to get a clean sine out of this signal ?, use a band pass ( 26 MHz centered ) filter to cut the harmonics ?

Don't know if it is the best way but when I had to do something similar to get a clean 50 ohm sine from an OCXO I took the output and fed it into one gate of a 74AC14 then took the output of that gate and fed it to the other 5 in parallel, combining all the outputs through resistors to give a 50 ohm impedance on the output. This gave a very clean square wave which I fed through a bog standard LC band pass filter. Beautiful sine wave output.

Offline dannyf

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Re: mistery oscillator
« Reply #8 on: February 07, 2015, 01:18:28 am »
Quote
Still I do not know what is the purpose for the 3 remaining pins, do I really need to use them ?

It is easy to tell if they are output or input pins: load them with a small-ish load (from 100ohm - 1k).

Quote
Does anyone have any idea how to get a clean sine out of this signal ?

Do you really need "clean sine" output?

It is going to be difficult. A "clean" way would be to use that to drive a DDS that generates a clean sine output.

Quote
, use a band pass ( 26 MHz centered ) filter to cut the harmonics ?

Yeah, not exactly "clean" however.
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Offline Vgkid

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Re: mistery oscillator
« Reply #9 on: February 07, 2015, 03:36:20 am »
I would monitor those 5v pins. One is probably an oven alarm, with the othèr a v-tune.
looking through my c-mac catalog, see if the indented pin changes states after a while, oven alarm.
« Last Edit: February 07, 2015, 03:44:09 am by Vgkid »
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