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4. Lens drive block
4-1. Focus drive
The focus motor is a stepping motor which is microstep-driven
by IC951. The 4 MHz clock signal (OSCIN) of the control sig-
nals (3-wire serial control (SDATA, SCLK, SENAB), VD) and
SUB CPU that are output from the ASIC (IC101) port is input
to IC951 so that IC951 can microstep control the focus motor.
Detection of the standard focusing motor position is carried
out by means of photointerruptor sensor inside the lens.
4-2. Zoom drive
The zoom motor is a stepping motor which is microstep-driven
by IC951. The 4 MHz clock signal (OSCIN) of the control sig-
nals (3-wire serial control (SDATA, SCLK, SENAB), VD) and
SUB CPU that are output from the ASIC (IC101) port is input
to IC951 so that IC951 can microstep control the zoom motor.
Detection of the standard zoom motor position is carried out
by means of photointerruptor sensor inside the lens.
4-3. ND filter
ND filter control is carried out by the control signals (ND ON
and ND OFF) that are output from the ASIC (IC101) port and
input to IC951 so that IC951 can drive the ND filter.
The 4 MHz clock signals (OSCIN) of the 3-wire serial control
signals (SDATA, SCLK, SENAB) and SUB CPU allow IC951 to
operate.
4-4. Iris drive
The drive method is a galvanometer type without braking coil.
The aperture opening amout is controlled as follows: the out-
put from the Hall sensor inside the lens is amplified by the Hall
amplifier circuit inside the IC971 lens drive IC, and the differ-
ence between the current and target aperture determined by
the resulting output and the exposure amout output from the
ASIC (IC101) is input to the servo amplifier circuit (IC971) to
keep the aperture automatically controlled to the target aper-
ture. The lens aperture control signal is output from IC971 and
is input to lens drive IN6B of IC951. IC951 functions as the
driver for driving the lens.
The 4 MHz clock signals (OSCIN) of the 3-wire serial control
signals (SDATA, SCLK, SENAB) and SUB CPU allow IC951 to
operate.
4-5. Shutter drive
Reverse voltage is applied to the above aperture coil to oper-
ate the shutter. With normal operation, the OC_EN and
OC_CONT signals that are output from the ASIC (IC101) are
maintained at a low level and when the shutter operates, the
OC_EN and OC_CONT signals switch to high, and after that
the SHUTTER + signal that is output from the ASIC (IC101)
becomes high and the shutter operates.
It is input to lens drive IN6B of IC951 with low level. IC951
functions as the driver for driving the lens.
The 4 MHz clock signals (OSCIN) of the 3-wire serial control
signals (SDATA, SCLK, SENAB) and SUB CPU allow IC951 to
operate.
5. Video clip recording and playback
5-1. Recording
The signals from the camera block are input to the ASIC where
they are processed, and the image data that is stored in the
SDRAM of IC103 is input to the IC102 MPEG4 CODEC LSI.
The CODEC LSI converts this data to encoded MPEG4 data,
after which it is returned to the ASIC as streaming data, and
the data is then written in sequence onto the SD card. At this
time, the audio signals that are input to the built-in microphone
are converted into digital data by the audio CODEC IC of IC183,
and they are then input via the ASIC to IC102 (MPEG4
CODEC). The audio data is then encoded (AAC) by IC102,
and then it is returned to the ASIC as streaming data and is
then written in sequence onto the SD card together with the
image signals described above.
5-2. Playback
The data is read from the SD card and input to IC102 as stream-
ing data. The encoded data is decoded into image data by
IC102 and then returned to the ASIC where it is displayed by
the LCD or on a TV monitor. At this time, the audio data is also
decoded by IC102, and it passes through the ASIC and is in-
put to IC183 as digital data. D/A conversion is carried out at
IC183, and the sound is then output to the speaker or to the
LINE OUT terminal.
6. Audio CODEC circuit (IC183)
The audio signals from the microphone are converted into 16-
bit digital data. AD conversion is carried out at a maximum
sampling frequency of 48 kHz.
During audio playback, the 16-bit digital data is converted into
analog signals and these drive the speaker or line out system.
DA conversion is carried out at a maximum sampling frequency
of 48 kHz.
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