[time-nuts] Help ID 5 MHz Distribution Box

[Bruce Griffiths]

Ed

A simple 3 transistor (2N3904) injection locked divider could be used to
produce +20dBm @ 5MHz in a 50 ohm load.
The 3 transistors combine the  VCO, phase detector and filter functions.
With high level injection the loop bandwidth is very high and the 5MHz
output phase noise will closely track the input signal phase noise
albeit a few dB below the input source phase noise.

An emitter coupled differential pair oscillator with 10MHz modulation of
the tail current source should work well.

This technique can be used effectively at frequencies for which no
digital divider is available.

It is important to choose an appropriate oscillator topology.
The above oscillator topology works well for frequency division by an
even integer.
Dividing by an odd integer requires a different oscillator topology

Bruce

Ed Palmer wrote:
>    So, the output levels looked good?  Then you were luckier than me.
>    I think I tried a fast and dirty divider off of a 10 MHz signal and it
>    worked very nicely.  I wasn't trying for 'time-nuts' quality, just
>    confirming basic functionality.  I used a 'scope in X-Y mode to view
>    both signals.  It's nice to see a Lissajous figure that doesn't make
>    you dizzy. :-)
>    Do you have a mixer kicking around?  Mix a 10 MHz and 15 MHz signal and
>    dump the results into the ref input.  I don't know if the output will
>    be at a high enough level, but it can't hurt!
>    Ed
>    Richard W. Solomon wrote:
>
> After numerous diversions, I got back to the box and got it working.
> Just as an experiment I stuck 10 MHz in the Reference Input, nada.
>
> So, I need to find a divider to get 5 MHz. I got lots of 10 MHz signals,
> even a 15 MHz but no 5 MHz. I really don't want another project just to
> build a divider. I'll look around.
>
> As she stands, it is pretty stable. But it would be nice to lock it to
> a GPDSO.
>
> Thanks again for the help,
>
> 73, Dick, W1KSZ
>
> -----Original Message-----
>
>
> From: Ed Palmer [1]<ed_palmer at sasktel.net>
> Sent: May 14, 2009 8:49 PM
> To: Discussion of precise time and frequency measurement [2]<time-nuts at febo.com>
> Subject: Re: [time-nuts] Help ID 5 MHz Distribution Box
>
>   Pinout is as follows - I think - remember that this is a work in
>   progress
>   1 - no connection
>   2 - alarm output - High = alarm, low = normal  (TTL)
>   3 - probably 'reference fail' - High = fail, low = normal (TTL)
>   4 - EFC okay - High if  4V8 < EFC < 7V5 else low (TTL)
>   5 - no connection
>   6 - buffered EFC voltage for oscillator
>   7 - no connection
>   8 - +10V reference output from oscillator - doesn't seem to be used for
>   anything
>   9 - +5V supply (input)
>   10 - External EFC input - only used when reference fails
>   11 - ground
>   12 -    "
>   13 -    "
>   14 - +24V supply (input) for oscillator
>   15 - +15V supply (input)
>   You talked about BNC.  Did you mean TNC?  My unit has TNC and SMA
>   connectors.  The SMA connectors are all outputs from the oscillator.
>   J3 (TNC) is the input from an external 5 MHz reference.  J4 (TNC) is
>   another output from the oscillator.  Approximate output levels are as
>   follows:
>   J2 - +7 dbm
>   J4 - 0 dbm
>   J5 - 0 dbm
>   J6 - +7 dbm
>   The purpose of the box is to discipline the internal oscillator to an
>   external reference and then distribute the oscillator's signal to four
>   outputs.  The level of the external reference can vary over an unknown
>   range because there's an internal AGC circuit.  I haven't figured out
>   the parameters of the low pass filter used on the output of the phase
>   detector.  Just for laughs I took the 10 MHz output of a Navsync CW-12
>   GPS board, divided it by 2, and fed it into the reference input.  The
>   result wasn't pretty.  Obviously, the circuit wants a smoother source.
>   On mine, the oscillator was defective.  I had to hack into it to fix a
>   broken wire on the output transformer.  I started a message thread a
>   few months back about how to hack into an oscillator - check the
>   archive if you need to.
>   Remember Engineering Rule #1 - Tune for minimum smoke!
>   Ed
>   Richard W. Solomon wrote:
>
> Was it that good a deal ?? I'll share my secret, I use Gixen to snipe
> on e-Pay. Sometimes it works, sometimes not.
>
> Do you know the connections for the DB-15 connector ? Then I can do the
> smoke test !!
> Also what are the BNC and SMA connectors for ? Basically, I know nothing
> but would appreciate any help. I will likewise share my findings.
>
> 73, Dick, W1KSZ
>
> -----Original Message-----
>
>
> From: Ed Palmer [1][3]<ed_palmer at sasktel.net>
> Sent: May 14, 2009 1:10 PM
> To: Discussion of precise time and frequency measurement [2][4]<time-nuts at febo.c
> om>
> Subject: Re: [time-nuts] Help ID 5 MHz Distribution Box
>
> Since you beat me by *THREE SECONDS* I shouldn't help you, but I have
> one of these boxes and have partially figured it out.  What do you want
> to know?
>
> Ed
>
> Richard W. Solomon wrote:
>
> I picked up a box from "over there" that says ..."5 MH REF DISTRIB"... ,
> which I assume stands for 5 MHz Reference Distribution. It was made
> by Satellite Transmission Systems of Hauppagge, NY. 2 BNC connectors
> on one end, 3 SMA's a Red LED Alarm light and a DB-15 connector.
>
> A real long shot, I know, but on the off-chance, does anyone know
> anything about this ? Anyone know if the company still exists ?
>
> Thanks, Dick, W1KSZ
>
>