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4. IC911 (CDS, AGC Circuit and A/D Converter)
The video signal which is output from the CCD is input to Pin
(29) of IC911. There are inside the sampling hold block, AGC
block and A/D converter block.
The setting of sampling phase and AGC amplifier is carried
out by serial data at Pin (37) of IC911. The video signal is
carried out A/D converter, and is output by 12-bit.
2~36 dB
CDS
PxGA
CCDIN
CLAMP
INTERNAL
CLOCKS
PRECISION
RG
HORIZONTAL
4
TIMING
DRIVERS
H1-H4
CORE
SYNC
GENERATOR
HD
Fig. 1-2. IC911 Block Diagram
VRB
VRT
VREF
12
DOUT
VGA
ADC
CLAMP
CLPOB
CLPDM
PBLK
CLI
INTERNAL
REGISTERS
VD
SL
SCK
SDATA
5. Lens drive block
5-1. Iris and shutter drive
When the drive signals (IRSTB, ICW, IOEB and ICLK) which
are output from the ASIC, the stepping motor is sine-wave
driven by the micro-step motor driver (IC952), and are then
used to drive the iris steps and open/close the shutter.
5-2. Focus drive
When the drive signals (FRSTB, FCW, FOEB and FCLK) which
are output from the ASIC, the focus stepping motor is sine-
wave driven by the micro-step motor driver (IC951). Detection
of the standard focusing positions is carried out by means of
the photointerruptor (FOCUS PI) inside the lens block.
5-3. Iris drive
The zoom stepping motor drive signals (ZIN1, ZIN2, ZIN3 and
ZIN4) which are output from the ASIC are used to drive by the
motor driver (IC953). Detection of the zoom positions is car-
ried out by means of photointerruptor (ZOOM PI) inside the
lens block.
– 3 –
I
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