cxa2555q Sony Electronics, cxa2555q Datasheet - Page 17

• Manufacturer Part Number: cxa2555q
• Description: Rf Amplifier For Cd Player/cd-rom
• Manufacturer: Sony Electronics

Mirror Circuit
The mirror circuit performs peak and bottom hold after RFI signal has been amplified. The peak hold is
executed with the time constant which follows the traverse signal of 100kHz for L/L mode (both of Pins 23 and
24 are connected to GND) and maximum 600kHz (adjustable with the DC voltage on Pin 17) for L/H, H/L, H/H
modes. The bottom hold is executed with the time constant which follows the rotation cycle envelope
fluctuation.
The mirror signal is output by comparing to the signal K (2/3 level of the J peak value which is peak-held with a
large time constant) where the difference of hold signals H and I is obtained. The mirror output is low for tracks
on the disc and high for the area between tracks (the mirror areas). In addition, a high signal is output when a
defect is detected. The mirror hold time constant must be sufficiently large in comparison with the traverse
signal.
RFO
RFI
(BOTTOM HOLD)
(MIRROR HOLD)
31
(PEAK HOLD)
3.125V
18k
44k
K
J
I
H
MIRR
(RFI)
Vc
RFO
Mirr Amp
G
39k
G
44p
10p
Vc
Vc
MIRR T
17
H
I
Peak &
Bottom
Hold
Open only
for L/L mode
– 17 –
80k
80k
1.3V
80k
Mirr
Dif Amp
80k
J
1.0V
51k
22k
H
L
0V
0V
0V
0V
Mirr
Hold
Amp
Mirr
Comparator
20k
Vcc
MIRR
K
19
18
CP
CXA2555Q
0.33µ
Vc