Sony Cyber-shot PRO DSC-D700, Service Manual

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4-7 DSC-D700 (UC,CE)
.
Camera head amplifier
The CCD output signal from IC204 is input through buffer amplifier Q201 to the
PIN and DIN pins of IC205 (CXA2096N). In IC201, the signal is reduced in
noise by correlative double sampling and output to the later stage by a gain of
approximately 6 dB. Moreover, the signal is clamped during CCD blank feeding
and then input to the gain control amplifier. In this unit, the ISO sensitivity (100,
200, or 400) is altered by changing the voltage at the AGCCONT pin (to 1.5 V
through 3.0 V) and controlling the gain.
The signal is also clamped in an A/D sample-and-hold circuit and CCD black
level block and then output from the DRVOUT pin to IC202 (ADS933) after the
DC potential is replaced with a VRB voltage using a blanking switch.
The DC offset of a DRVOUT signal is controlled by applying a voltage to the
OFFSET pin.
VRT and VRB voltages are supplied to the VRT and VRB pins of IC202 using a
(10-bit A/D) reference voltage driver for IC202. (VRT = 2.4 V and VRB = 1.4 V)
.
D/A converter
The D/A converter converts the data signal from IC301 (HD64F3437TF16) on the
CA-33 board by IC206 (MB88347LPFV) and produces an offset/AGC control
signal.
.
10-bit A/D converter
The signal from IC205 is converted into a 10-bit digital signal by IC202. The
reference signal input for
T
Vref (VRT - VRB = approx. 1 V) is approximately
300 mV. A D range of 300 % is secured in this case.
.
Camera signal processing display
A 10-bit digital signal is input from IC202 to pins AD0 through AD9 and output
from pins D0Y0 through D0Y7 and D0C0 through D0C7 to the FM-63 board
according to the Y/UV 4:2:2 format. IC203 is controlled by the MCK clock from
IC201, the XCAMHRO/XCAMFRO sync signal from the FM-63 board, and the
serial control signal from a camera microcomputer on the CA-33 board.
The major functions of IC203 are as follows:
. Variable gamma circuit
.
Hue correction circuit
.
Contour correction circuit
.
AE/AWB detection circuit
. Automatic CCD fault detection and correction circuit
. Sync signal generator circuit (FRO, HRO, MFRO, and MHRO signals)