[Arny Krueger]

"William Sommerwerck" wrote in message
. ..
The automatic adjustment looks at phase difference between
the channels and drives a motor which adjusts the head.

Actually, that isn't the way it works. As the phase between the channels
of
a stereo recording has no necessary standard or fixed relationship, it's
not
a useful way to set azimuth.

In the Nakamichi, the outermost track (the one closest to the tape edge)
is
split into two head gaps, each with its own amplification. The head block
is
moved until the HF output of these heads peaks. (Or is it that the phase
difference is minimized?) Anyhow...

I'd put my money on nulling based on minimizing the phase difference. It is
going to work well with less regard for program material HF content.

We had circuits like this in the missile systems I worked on in the Army.
They did a really good job of getting missiles to collide with airplanes,
radar receivers to ignore ground clutter, and transmitters to have minimal
RF noise on their carrier.