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6-3-2. Clock Function
The main controller contains a built-in clock function. The
clock is provided with its own crystal oscillator (32.768 kHz).
The time and date are read and displayed by reading the
data from this clock.
This clock is designed to continue operating from the
backup lithium battery even when the main battery of the
unit is removed.
For details on setting the clock and date and on the display
method, refer to the "Instruction Manual."
6-3-3. Linear Tape Counter
The amount of tape travel (recording time) is calculated
from the rotation of the capstan motor and is displayed on
the tape counter. Thus the counter advances even for
unrecorded sections of the tape.
The tape counter is operated by means of the COUNTER
RESET key and the COUNTER MEMORY key.
6-3-4. Camera Preset Dlsplay
7 different modes (preset modes) can be set to suit the
filming conditions. The PRESET switch is read by means of
matrix input, and the reading is sent to the camera circuit by
a serial bus, while at the same time an icon is displayed in
the viewfinder.
For more information on the PRESET mode, refer to the
"Instruction Manual."
LITHIUM
UN REG +
CAMERA
VTR
DDC
5 V
VOLTAGE
REGULATOR
SWITCH
CONTROL
IC335
VTR POWER ON
DDC
Fig. 6-3. Power Control Circuit
In addition, AUTO/MANUAL focus and blackback screen
information for the camera is also transmitted to the camera
by a serial bus.
6-4. VIDEO AND AUDIO CIRCUIT CONTROL
The mode select signal and the timing switchover control
signal are sent to the video and audio circuits.
These are in most cases synchronised with the rotation of
the drum motor. When the FADE mode is selected, the
PWM waveform (FADE) which is output by the main
controller is converted to a voltage value by a low-pass filter
by means of OP AMP, after which it is sent to the video and
audio circuits as the fade-in and fade-out signal at the
beginning and end of recording respectively.
6-5. POWER CONTROL
For details on the power system of the whole deck, refer to
the block diagram.
The following is a description of the power startup and
switching-off processing.
UN REG voltage or the regulated ALWAYS +5 V voltage is
supplied to the system control circuit and the servo circuit
directly from the battery.
r
- SWITCH
-
-
BATT OFF
POWER SW
- 4-34 -
-
-,
-
-
-
-
- -
L l + ALS
Vee
IC351
CXP80724
MAIN
CONTROLLER
CAMERA ON
SIS 5
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