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Ve=iF x 403KQ, and
Ve=iE x 260K2 x Ra(Re+22K)+(Ra+260K).
f
The tracking error amplifier is the difference between the E |-V amplifier ouput and the F -V amplifier
output, this output is (E-F).
Vre=(Ve-VF) X 3.2
=(iE-iF) x 1290K 2
MIRROR CIRCUIT
This circuit, after amplifying the RF! signal, holds its bottom and peak. The peak hold is done with a time
constant able to track down a 30kHz traverse and the bottom hold. This is done with a time constant able
to track down envelope fluctuations in the revolving cycle.
MIRROR HOLD AMP
MIRROR
COMPARATOR
(PEAK HOLD)
a
<<
a
oY
|
S
feiva
(BOTTOM HOLD)
J
Ky
(MIRROR HOLD)
MIRR
With the differential amplification of these peak and bottom hold signals, H and |, the envelope signal J
(demodulated to DC) is obtained. Two-thirds of the peak value of this signal J is held with a large time
constant for the signal K. When K is compared with J, a mirror output is obtained. That is, the mirror output
gives "L" on the disc track, "H" between tracks (mirror section) and also "H" in the defect detection. The
time constant for the mirror hold must be sufficiently larger than that of the traverse signal.
—16-
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