As I understand it, the Scout controls the frq as follows: When the Scout
is turned on the CPU, working as a frq counter, measures the frq of the
PTO. Using this frq as a reference it attempts to maintain the PTO at this
frq by adjusting the current through a diode that acts as a small capacitor
to change the PTO frq. When the frq change gets out of the range of this
circuit the system resets to the new frq and the control loop is
reinitialized. This is the jump that is noticed. It would also be noticed
if the CPU was over taxed running itself as a keyer at a high keying rate.
This control loop is disabled when the change in frq per unit of time is
greater then a predetermined limit, such as when you turn the dial to set a
new frq. When you stop turning the dial the loop will reset to the new frq
after some fraction of a second. This is a very simple and elegant circuit
and does a very good job, at least on my Scout!
Bill Ames
KB1LG
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