Hi Arv,
"Consider H&P as a PLL design that locks on multiples of the reference frequency.? It?
adjusts slower than a PLL but otherwise many of the PLL design formula can be used."
Its not a PLL, I've designed more than a few.? Its a FLL, the differnce is one your
locked to the phase of a reference signal and the other you measure frequency
and correct.? The latter allow for some latitude depending on count resolution.
My first H&P was a signal generator locked to the LSB of a frequency counter.
Handy gadget.? ?
I would later find a HP sychronizer for the HP603 signal generator and study
how that worked.? That was phase locking to harmonics.? By the early 70s
I was doing full out /n and sampling? PLL systems.
My reference is to some of the simpler circuit used short counters and the amount
of drift tolerable would have the frequency of the VFO bouncing back and forth
depending on the filter RC time constant and the count resolution.? Those would?
drift between finite points and those were defined by the count resolution.
A stable VFO can be enhanced but poor and unstable VFO should be fixed first then?
improved.? Most of the time a frequency readout is needed just to understand the drift.
Allison
