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SSC-M370/M370CE
@ SYNC Signal Generation
Inputting the CL signal makes
the IC406 generate the
various timing signals necessary for making the video
signals.
e SYNC
: Composite SYNC signal
e HD, VD:
Horizontal or Vertical SYNC signal
e BLK ~ : Blanking signal
© VCO for External Synchronism
The LC-31 board generates the 28 MHz basic clock necessary
for external synchronism, and it has the following input
and output.
e Oscillation ON/OFF control input
e Oscillation frequency contro! input
e 28 Mt basic clock output
© External Synchronism
The followings make the signals necessary for external
synchronism; 0408, 0409, 0410,0411, 0413, 0414, 1C411,
1C412, 1C413 and1C415.
The 0408, 0409, 0410, 0411, 0413 and 0414 execute the
synchronizing separation of the external SYNC signal, and
the 1C412 and1IC413 produce the VD and HD pulses. The VD
pulse resets the SYNC signal generator (IC406), and the HD
pulse executes the phase comparison at the HD output of
the SYNC signal generator (IC406) and the IC411.
The phase comparison output is smoothed by the LPF and
becomes the oscillation frequency control input of the LC-
31 board.
@ External Synchronism Horizontal Phase Adjustment
The IC 412 and1C416 adjust the horizontal phase at external
synchronism.
The microcomputer
on the FC-30
board
executes the adjustment operated by the SW701
and
SW702 onthe
CB-31 board.
V SUB Voltage Supply / CCD IRIS Circuit
This circuit supplies the specified voltage to the overflow
drain ofthe CCD imager. The Q401 and 0402 are regulators
whose standard voltage is V SUB control voltage.
The 12 Ch D/A converter (1C504) output on the FC-30 board
sets the V SUB control voltage so that the overflow drain
voltage of the CCD imager is the standard voltage. The
1C408 produces the charge discard pulse for shutter speed
control from the CCD IRIS control signal produced by the
FC-30
board and from the X SUB signal output by the
IC405.
© IRIS/AGC
The output for the IRIS detection is output from the IC401
4 PIN to the H-30 board as the video signal (No SYNC
signal).
The circuit centering on the Q405 is the AGC detection
circuit, and composes the AGC group with the operational
amplifier inside the 1C401.
3-2
3-3. PR-32 BOARD
The luminance signal (Y output) and the clamp pulse (CLP
3) from the TG-31 board gothrough the DC restorers of the
Q303
and
Q304,
and
the
signal
undergoes
gamma
compensation at the 0301, 0302, and IC301 (1/2). The
RV301 is a variable resistor for gamma adjustment. Next,
they go through the trap circuit of 14 [MHz] (CT301 is a
variable capacitor for 14 [MHz] trap adjustment) andIC301
(2/2), and are input to the IC330 (encoder) @3 PIN.
Then they go through the delay line FL301 to make the
aperture compensation signal, and are input to the
@ PIN.
The level of this signal is adjusted by the voltage of the
1C330 @6 PIN. For a low luminance subject, the voltage of
the @8 PIN is raised by the AGC CONT voltage to decrease
the H aperture compensation signal and noise.
The blanking signal and the sync signal are supplied to the
1C330. Also, the voltage of the AGC CONT, Y ievel (IC330
@0 PIN), and the setup (IC330 @ PIN) are in the memory of
the IC505/FC-30 board.
The !C330 @ PIN is the output of the composite video
signal and is supplied and output to the IC360.
3-4. FC-30 BOARD
This board deal with the function system
@ Electronic Shutter/CCD IRIS Circuit
In the electronic shutter circuit, the microcomputer IC505
reads the setting of the SW501 (10 position rotary switch),
and outputs the EDO, ED1, ED2 and SMD2 signals to the
1C405 on the TG-31 board through the MB-31 board.
Inthe CCD IRIS circuit, the microcomputer IC505 changes
the
electronic-shutter
speed
automatically
and
successively according to the subject illumination. The
1C508, IC509, 1C510, Q509 and Q510 produce a saw-tooth
wave of 1 field period. On the other hand, the |C505 of TG-
31 board produces the shutter-speed-control voltage based
on the IRIS signal of the 1C401 of TG-31 board. The IC502
compares the both signals, produces the SWND
signal
whose pulse length accords with the subject illumination,
and outputs it to the TG-31 board.
@ Microcomputer Circuit
The microcomputer circuit deals with the adjustment of
the signal process system in addition to the above @ and
@ functions.
The IC504 is the 12Ch D/A converters (Electronic volumes),
and output the 12Ch analog voltage respectively according
to the data set by the IC505. The IC505 is connected with
the adjustment fixture by the CN502, then the data specified
by the fixture is set into the IC504 through the IC505 so that
they output the analog voltage for adjustment.
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