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The communication with MAIN CPU (IC101) on MAIN board is
established by the serial signals (RXD_232C, TXD_232C) via CN902.
Also, the communication with CDS&AGC (IC801) and Video DSP (IC803)
is established by the serial signals (CS_CDS, SDI_DSP, SDCLK_DSP,
SDO_DSP, SLD_DSP). At the time of CPU (IC902) program upgrade, it is
set to the upgrade mode by BOOT1 and BOOT2 signal in MAIN CPU
(IC101), and the data is transferred via the serial signals (RXD_232C,
TXD_232C) and written.
The timing synchronization with Video DSP (IC803) is performed by
FV_DSP, EP1_DSP and EP2_DSP. The lens control is performed by
signals including PWM connected to the lens board via CN904.
15.1.2.2. Video Signal Process Block
- CDS (IC801)
Power-supply voltages: 3.3V
Package: 36pin QFP
Performs CDS (Correlate Double Sampling) process for CCD output
signal from CCD board, AGC (Auto Gain Control) process and A/D
conversion (10bit)
CCD output signal is sampled with SP1 and SP2 signal to reduce noise
in CDS circuit. Then, after being adjusted to the specified level in
accordance with the serial signal (CS_CDS, SDI_DSP, SDCLK_DSP)
instruction from CAMERA CPU (IC902) in GCA circuit, it is converted to
10bit, the digital signal with the sampling frequency: 14,31818 MHz of
ADCLK input signal by A/D converter. This output signal is adjusted in
order that OB (Optical Black) on CCD output signal shall be standard
level by OBP signal.
- VIDEO DSP (IC803)
Power-supply voltages: +3.3V
Package: 120pin QFP
Clock frequency: 28.636MHz (X801)
Processes CDS IC (IC801) output signal and outputs Y signal and C
signal. Outputs CCD drive signal.
Writing each setting to this IC and reading of data is performed by the
serial signal (CS_CDS, SDI_DSP, SDCLK_DSP, SDO_DSP, SLD_DSP) in
CAMERA CPU.
<Video signal process>
The signal input from CDS IC (IC801) is composed of luminance signal process and color signal
process.
- Luminance signal process
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