# [time-nuts] M12T and M12M

Magnus Danielson cfmd at bredband.net
Thu Jun 15 04:18:11 EDT 2006

```From: "Matt Ettus" <boyscout at gmail.com>
Subject: Re: [time-nuts] M12T and M12M
Date: Wed, 14 Jun 2006 16:48:30 -0700

> Is there logic (that I'm missing) to what seems like such an odd frequency?

Hint: 16 x 1023000 = 16368000 Hz

1,023 MHz match the chipping rate of C/A code. Perfect match is not the end of
the world since you need to compensate for doppler and deviations.

The actual frequency 16367000 is however a bit strange since it is
2*2*2*5*5*5*13*1259.

Cheers,
Magnus

> Matt
>
> On 6/14/06, Randy Warner <Randy at synergy-gps.com> wrote:
> > Tom,
> >
> > You're close. The M12 series actually has a 16.367 MHz crystal (TCXO in
> > the M12M). What enables the M12 to get down to +/-12 ns is that it can
> > place the 1PPS on both the rising and falling edges of the clock.
> >
> > Randy
> >
> > ________________________________________________________________________
> > ________________________________
> >
> > -----Original Message-----
> > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> > Behalf Of Tom Van Baak
> > Sent: Wednesday, June 14, 2006 2:39 PM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] M12T and M12M
> >
> > > Can somebody tell me the master clock frequency of the M12T and M12M
> > >
> > > Thanks,
> > > Matt
> >
> > The old Oncore VP used a 9.54 MHz oscillator and had sawtooth error of
> > about 104 ns (+/- 52 ns). The
> > M12 has jitter closer to 25 ns (+/- 12 ns) which would imply a clock
> > frequency of approximately 40 MHz.
> >
> > http://www.leapsecond.com/pages/m12/sawtooth.htm
> >
> > /tvb
> >
> >
> >
> > _______________________________________________
> > time-nuts mailing list
> > time-nuts at febo.com
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >
> > _______________________________________________
> > time-nuts mailing list
> > time-nuts at febo.com
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >
>
> _______________________________________________
> time-nuts mailing list
> time-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>

```