Sanyo VPC-E1W Service Manual page 6

4. Lens drive block
4-1. Focus drive
The three control signals (LENS_SD, LENS_CK and
LENS_EN) which are output from the ASIC (IC101) are con-
verted into drive pulses (FOCUS A+, FOCUS A–, FOCUS B+
and FOCUS B–) by the motor driver (IC951), and are then
used to drive micro step the stepping motor for focusing op-
eration.
Detection of the standard focusing positions is carried out by
photointerruptor (F_SENSE) inside the lens block.
4-2. Zoom drive
The three control signals (LENS_SD, LENS_CK and
LENS_EN) which are output from ASIC (IC101) are converted
into drive pulses (ZOOM A+, ZOOM A–, ZOOM B+ and ZOOM
B–) by the motor driver (IC951), and are then used to drive
micro step the stepping motor for zoom operation.
Detection of the standard zooming positions is carried out by
photointerruptor (Z_SENSE) inside the lens block.
4-3. ND filter drive
The ND filter drive signals (NDON and NDOFF) which are out-
put from the ASIC (IC101) are used to drive (ND + and ND –)
by the motor driver (IC951), and then the ND filter is inserted
into and removed from the beam path.
4-4. Iris drive
The drive method is a galvanometer type without braking coil.
The output from the Hall sensor inside the lens is amplified by
the Hall amplifier circuit inside the IC971 lens drive IC, and the
difference 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 ap-
erture. 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.
4-5. Shutter drive
Reverse voltage is applied to the above aperture drive coil to
operate the shutter. When the shutter operates, the OC_EN
and OC_CONT signals are maintained at a high level, it is
input to IN6B of IC951 with low level.
At the same time the SHUTTER + signal that is output from
the ASIC (IC101) becomes high (input to IN6A of IC951) and
the shutter operates. IC951 functions as the driver for driving
the lens.
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
IC102 SDRAM 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 H. 264
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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