[time-nuts] 10MHz to 32MHz?

Bruce Lane kyrrin at bluefeathertech.com
Sun Apr 22 12:05:46 EDT 2007


Good day,

*********** REPLY SEPARATOR  ***********

On 22-Apr-07 at 21:11 Lester Veenstra M0YCM K1YCM wrote:

>And if the 32 mhz source is a sealed unit, I suspect you will find that
>once
>you mechanically set it as close as practical, that varying the Vcc will
>allow you to use it as a narrow VCO.

	Fair enough. However, I need some clarification. Magnus used some terms that are utterly unfamiliar to me. See below.

	<snippety>

>The most straight-forward fashion is naturally to lock it through a PLL.
>
>Highest common comparator frequency is 2 MHz, so divide 10 MHz by 5 and 32
>by
>16, compare with SR-gate, use either a passive lag or better yeat, and
>active loop. Three digital ICs and an op-amp. If the 32 MHz reference is a crystal
>then hooking into the caps for a varicap is easy enought for most hams.

	I suspect a full-blown design engineer would have no trouble following this, Magnus, and I thank you for your post, but I'm afraid you lost me on a couple of things.

	What is meant by 'passive lag?'

	Likewise: 'active loop?'

	On the IC's: I can guess at two of the digital side (divide-by-5 and divide-by-16 counters), but what would the third one be?

	The op-amp I can guess at -- probably high frequency/high slew rate, I'm thinking something in the LF series. And I'm also guessing that it would be used to compare the two divided-down signals, and produce a difference voltage if they're out of phase?

	The part about "hooking into the caps for a varicap" means nothing to me in its current form. Are you trying to say I'd need a varactor effect for the 32MHz source? (That's the only idea that makes sense to me).

	Thanks much.


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Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
kyrrin (at) bluefeathertech do/t c=o=m
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