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Dick · April 10th 07, 04:32 PM posted to rec.radio.amateur.equipment

On 10 Apr 2007 04:11:25 GMT, (Michael Black)
wrote:

pltrgyst ) writes:
On 9 Apr 2007 18:53:01 GMT, (Michael Black) wrote:

A Q-multiplier is a regenerative stage.

It's prime was in the days of the 455KHz IF, where the improved selectivity
would actually make a difference. At a higher frequency, it would still
increase the selectivity of the tuned circuit, but not enough to narrow
the passband for voice or CW.

So what about audio Q-multipliers? Do they function on the same principle?

-- Larry

Originally yes, though I've seen "audio Q-multipliers" described in
construction articles that are more strictly average audio filters.

They may even come out of the same place. The selectoject was described
in QST in the late forties, by O. G. Villard, and it uses the principle
of regneration to get better selectivity at audio. And O. G. Villard is
the name I'd associate with the use of the Q-Multiplier for better
reception of AM (there are references to a QST article by him on that topic
in an early ARRL SSB manual). But I've never seen a specific link between
the selectoject and the Q-Multiplier at the IF of a receiver, so I don't know
if he came up with the IF Q-multiplier as we know it, or someone else did.
Certainly O. G. Villard, who died only three years ago, came up with
quite a few things important to amateur radio, including a lot of work
in SSB in the early days.

Michael VE2BVW

Interestingly, this month's QST in the 50 Years Ago column lists a
variable band width Q-Multiplier by Ronald Ives (April 1957.) The
article references the original Villard article in the April 1952
issue of "Electronics" magazine.

Dick - W6CCD

--
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