Sanyo VPC-S120DB, Руководство по обслуживанию

Страница: 5 / 47

– 5 –
1-2. CP1 CIRCUIT DESCRIPTION
1. Circuit Description
1-1. Signal processor
1. Gamma correction circuit
This circuit performs (gamma) correction in order to maintain
a linear relationship between the light input to the camera
and the light output from the picture screen.
2. Color generation circuit
This circuit converts the CCD data into RGB signals.
3. Matrix circuit
This circuit generates the Y signals, R-Y signals and B-Y sig-
nals from the RGB signals.
4. Horizontal and vertical aperture circuit
This circuit is used gemerate the aperture signal.
1-2. AE/AWB and AF computing circuit
The AE/AWB carries out computation based on a 64-seg-
ment screen, and the AF carries out computations based on
a 6-segment screen.
1-3. SDRAM controller
This circuit outputs address, RAS, CAS and AS data for con-
trolling the SDRAM. It also refreshes the SDRAM.
1-4. PIO/PWM/SIO for LCD
It possible to switch be-tween individual input/output and PWM
input/output.
1-5. TG/SG
Timing generated for 12 million pixel CCD control.
1-6. Digital encoder
It generates chroma signal from color difference signal.
2. Outline of Operation
When the shutter opens, the ASIC starts shooting operation.
When the TG/SG drives the CCD, picture data passes through
the A/D and CDS, and is then input to the ASIC as the LVDS.
The AF, AE, AWB, shutter, and AGC value are computed from
this data, and three exposures are made to obtain the opti-
mum picture. The data which has already been stored in the
SDRAM is read by the CPU and color generation is carried
out. At this time, correction of the lens distortion which is a
characteristic of wide-angle lenses is carried out.
After AWB and g processing are carried out, a matrix is gen-
erated and aperture correction is carried out for the Y signal,
and the data is then compressed by JPEG and is then writ-
ten to card memory (SD card).
When the data is to be output to an external device, it is taken
data from the memory and output via the USB. When played
back on the LCD and monitor, data is transferred from memery
to the SDRAM, and the image is then elongated so that it is
displayed over the SDRAM display area.
3. LCD Block
The LCD display circuit is located on the CP1 board, and
consists of components such as a power circuit.
The signals from the ASIC are 8-bit digital signals, that is
input to the LCD directly. The 8-bit digital signals are con-
verted to RGB signals inside the LCD driver circuit.
The LCD is input signals from ASIC directly to the LCD, and
function such as image quality are controlled.
In addition, the timing pulses for signals other than the video
signals are also input from the ASIC directory to the LCD.