[time-nuts] 10 MHz -> 16 MHz

Bruce Griffiths bruce.griffiths at xtra.co.nz
Wed Oct 3 13:51:03 EDT 2018


Brian
There are 2 parallel feedback paths one tuned to 6MHz and the other tuned to 16MHz.
They can either share the same amp or use separate amplifiers. There's a NIST paper on using them to divide by factors other than 2 (e.g. 3, 5 etc).
https://tf.nist.gov/general/pdf/1890.pdf

Bruce
> On 04 October 2018 at 00:54 "Brian, WA1ZMS" <wa1zms at att.net> wrote:
> 
> 
> Bruce-
> 
> Does such a dual conjugate regen divider use a single mixer with the BPFs in parallel?   Or are there multiple loops?  I'm trying to visualize the topology.
> 
> I've built a few divide-by-2 regen dividers (both worked very well) but nothing else.
> 
> -Brian
> 
> 
> > On Sep 30, 2018, at 4:25 PM, Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:
> > 
> > A low phase noise method is to use a dual conjugate regenerative divider with 6MHz and 16Mhz bandpass filters in the feedback loop to produce 16Mhz output.
> > 
> > For 12MHz output use 2MHz and 12MHz bandpass filters in the feedback loop. 
> > 
> > Bruce
> >> On 01 October 2018 at 09:05 Bob kb8tq <kb8tq at n1k.org> wrote:
> >> 
> >> 
> >> Hi
> >> 
> >> If (as originally specified) noise and jitter are not a big deal - there are a lot 
> >> of chips out there like the ICS570. They are designed to do weird ratio frequency
> >> conversions so 10 to 12 or 10 to 16 are trivial for them. The Clockblock board was
> >> one way to get it all put together. 
> >> 
> >> Bob
> >> 
> >>> On Sep 30, 2018, at 12:05 PM, Gerhard Hoffmann <dk4xp at arcor.de> wrote:
> >>> 
> >>> 
> >>>> Am 30.09.2018 um 16:49 schrieb Attila Kinali:
> >>>> 
> >>>> The simplest way I can think of is the following:
> >>>> Use a 74LV8154 to divide the 10MHz down to 152.587890625Hz.
> >>>> Use the capture timer unit of the uC to measure the phase of the
> >>>> pulse. Use any kind of DAC (internal, external, PWM,...) to steer
> >>>> the 16MHz VCO. Depending on how fast the timer unit runs, this
> >>>> will give you something in the order of 10-200ns dead-band.
> >>>> By choosing the right frequency for the timer unit, one can
> >>>> get it to "dither" a bit and then use averaging.
> >>>> 
> >>>> For lower jitter, use one half of a Nutt interpolator
> >>>> to get the timing difference between the 152Hz signal
> >>>> and the 16MHz (ie similar to what the SRS FS740 does).
> >>>> Use something akin Nick Sayer's time-to-amplitude converter
> >>>> for the fine measurement.
> >>>> 
> >>>> Same works equally well for 12MHz.
> >>>> 
> >>>> 
> 
> 
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