On 06/08/2017 15:27, Chris wrote:
On 08/06/17 12:52, Gareth's Downstairs Computer wrote:
On 06/08/2017 12:24, Chris wrote:
On 08/06/17 10:38, Jeff wrote:

You are making pointless distinctions. A phase locked loop is not
defined by its mechanics but by the nature of its control. The Shortt
clock maintains the relative *phase* of the two clocks by brief
adjustments to the frequency via a spring. This is controlled by
measuring the relative *phase* of the two clocks.


Wrong! It does NOT measure the relative phase, it makes NO measurement
of the phase difference. All it does is detect if there is a phase lag
of any degree. It could be a fraction of a degree or 180 degrees, the
same correction is then applied regardless.

It's that simple. You are just making things more complicated by
talking about the details of how the adjustment works and the time
function of the frequency. NO PLL can keep the two clocks perfectly in
sync.

Calling it open loop is just absurd. The loop is closed because it
*measures* the phase of the clocks and adjusts the phase according to
the measurement. It may be binary, but the adjustment is controlled by
the measurement.

Wrong again it is open loop, there is no measurement, just the same
adjustment regardless of the phase difference.

Jeff



Might be easier to define a set entitled "Locked Oscillators, of which
the phase locked loop, injection locked and hit and miss synchronised
are all members.

Are there other candidates ?...

From pre-war, the Goyder Lock?

Which raises an interesting point; before the 3-tier
coffer-filling fiasco was the spawn of the RSCB, the candidature
for the RAE tended to know all about the history of amateur radio
before getting their licence, but now they seem to know
sweet FA even after getting their licences, such as the
difference between sideband and sidetone.




Hadn't heard of that, so looked it up and found:

http://www.dxmaps.com/discuss/oven.html

Which was an interesting read, but not enlightening.

Some of the early scope timebases, puckle, for example sounded
interesting, but they were effectively injection lock, of course.
I guess a triggered timebase is a variation of the hit and miss model.

Couldn't grok the relevance of the following paragraph above :-)...


It relates to the abysmal lack of technical acumen amongst those
who are today's would-br radio amateurs, most of whom are
really CBers-masquerading-as-radio-hams, identifiable by their
M3 and M6 callsigns past and present.