[time-nuts] RE: phase locking Rb to GPS

[Magnus Danielson]

From: "Christopher Hoover" <ch at murgatroid.com>
Subject: [time-nuts] RE: phase locking Rb to GPS (was time-nuts Digest, Vol 14, Issue 30)
Date: Sun, 18 Sep 2005 11:40:36 -0700
Message-ID: <20050918184006.D6ACEA00031 at mail.murgatroid.com>

> 
> On 9/18 "Tom Clark, W3IWI" <w3iwi at toad.net> wrote:
> 
>    The frequency knob that you tweak to correct the Rb frequency
>    passes some tens of ma thru a coil surrounding the RF interaction
>    region. If you try to phase lock a Rb to GPS, you need to develop
>    a current source error signal.
> 
> Hmmm ... can you say more about this current source error signal?    
> 
> I've been thinking of locking my Rb standard to GPS.  I was simply going to
> use the same circuit (1 pps, 10 MHz in; analog EFC voltage out) that I have
> running with my OXCO but with different filter and EFC DAC coefficients.
> 
> So is this not sufficient to phase lock GPS to a Rb standard?

In practice you usually see a voltage input on Rb standard. I have one on mine,
it is directly converted into current which drives the C-field coil.

Cheers,
Magnus