EMRFD Message Archive 1431
Message Date From Subject 1431 2008-02-17 08:16:27 wk0qkr1 HuffPuff circuit to control a crystal oscillator I have done a search of the web (how complete well that is a guess
anyway) I have not found any good reference to control a crystal
oscillator with a HuffPuff. All of the discussion I have found has
been then design of the HuffPuff itself but incorporating it with other
circuits seem to be left to the experimenter.
Working with LC oscillators seems to be the most common interface.
Now, I would like to explore other options.
Has anyone done this, any suggested circuits, or anyone willing to
work with me on test circuits?
1432 2008-02-17 09:09:02 Henk Fidder Re: HuffPuff circuit to control a crystal oscillator -Hi Bill,
I have been thinking about locking a vxco to my (surplus :-)) King avionics Rubidium
standard for QRSS use....
Henk/PA0DSD-- In firstname.lastname@example.org, "wk0qkr1"
> I have done a search of the web (how complete well that is a guess
> anyway) I have not found any good reference to control a crystal
> oscillator with a HuffPuff. All of the discussion I have found has
> been then design of the HuffPuff itself but incorporating it with other
> circuits seem to be left to the experimenter.
> Working with LC oscillators seems to be the most common interface.
> Now, I would like to explore other options.
> Has anyone done this, any suggested circuits, or anyone willing to
> work with me on test circuits?
1433 2008-02-17 15:33:02 Johan H. Bodin Re: HuffPuff circuit to control a crystal oscillator Hi Bill,
since you want to control an XTAL oscillator with huff & puff I assume that you
have a reference frequency that is much better than the XTAL osc' itself?
I am using a slightly modified version of W5OJM's design to discipline an 10 MHz
OCXO to the 1Hz output from a GPS receiver (Motorola Oncore UT+). It is not
exactly a huff & puff circuit, rather a P-I servo algorithm in PIC firmware, but
the frequency accuracy is almost "ridiculous". See
Here's a good starting point for exploring huff & puff:
Peter Lawton G7XIH has written a huff & puff simulator. Just input the frequency
division ratios and the VCO/VCXO tuning rate when a solid "logical 1" is input
to the LFP/integrator (Hz/second) and the software will predict the future... :
1434 2008-02-18 06:02:54 Allison Parent Re: HuffPuff circuit to control a crystal oscillator 1435 2008-02-19 05:11:29 w4zcb77 Re: HuffPuff circuit to control a crystal oscillator > Why would you do this? The reason for H&P was to stablize VFOsthe
> to get near crystal stability. Crystal oscillators are very stable
> and any drift is usually directly related to thermal effects on the
> crystal itself. The thermal effects are easily controllable with
> oldest and best but power hungry being an oven at 50-70C. Secondto
> that is TCXO applying temerature compensation via resistanceis
> thermometer and applying a correction to a varicap based on some
> predetermined curve.
> However if you want the ultimate in stability the usual path then
> GPS referenced when the Crystal osc is tuned over a rance on usualyGM Allison. I think the question was as to using a Rhubidium
> less than 100cycles in a PLL system referenced to the very accurate
> GPS time clock. This is usually used when you want 10-8 or better
> stability and accuracy.
standard to discipline a lower accuracy crystal to Rhubidium
standards by slaving it with a Huff n Puff in lieu of a PLL. By the
nature of the Huff n Puff, where the controlled oscillator is never
on frequency (except when passing thru) but always trimmed in the
direction of being on frequency, I too suspect he would be better
served to use a PLL instead. However, in the interest of the
experiment I would like to know the result, (increased jitter in
lieu of increased phase noise?) particularly when using the G7IXH
stabilizer instead of Klaas's circuit. I have one of those built and
functional. (Functional only after Pete steered me to a solder
bridge on my board that was making me unidirectional!) Now all I
need is the Rhubidium standard.
1436 2008-02-19 11:26:16 Jose HF Silva Re: HuffPuff circuit to control a crystal oscillator What about this:
A Simple Frequency Stabiliser, by Olivier F5LVG
73 de Joe / CT1AXG
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