Sanyo VPC-S6U Service Manual

Also see for VPC-S6: User guide

Contents

– 5 –1-2. CP1 CIRCUIT DESCRIPTION1. Circuit Description1-1. Digital clampThe optical black section of the CCD extracts averaged val-ues from the subsequent data to make the black level of theCCD output data uniform for each line. The optical black sec-tion of the CCD averaged value for each line is taken as thesum of the value for the previous line multiplied by the coeffi-cient k and the value for the current line multiplied by thecoefficient (k-1).1-2. Signal processor1. γ correction circuitThis circuit performs (gamma) correction in order to maintaina linear relationship between the light input to the cameraand the light output from the picture screen.2. Color generation circuitThis circuit converts the CCD data into RGB signals.3. Matrix circuitThis circuit generates the Y signals, R-Y signals and B-Y sig-nals from the RGB signals.4. Horizontal and vertical aperture circuitThis circuit is used gemerate the aperture signal.1-3. AE/AWB and AF computing circuitThe AE/AWB carries out computation based on a 256-seg-ment screen, and the AF carries out computations based ona 11-segment screen.1-4. SDRAM controllerThis circuit outputs address, RAS, CAS and AS data for con-trolling the SDRAM. It also refreshes the SDRAM.1-5. Communication control1. SIOThis is the interface for the 8-bit microprocessor.2. PIO/PWM/SIO for LCD8-bit parallel input and output makes it possible to switch be-tween individual input/output and PWM input/output. It is pre-pared for 16-bit parallel output.1-6. TG/SGTiming generated for 6 million pixel CCD control.1-7. Digital encorderIt generates chroma signal from color difference signal.1-8. JPEG encorder and decorderIt is compressed and elongated the data by JPEG system.2. Outline of OperationWhen the shutter opens, the reset signals and the serial sig-nals (“take a picture” commands) from the 8-bit microproces-sor are input to ASIC (IC101) and operation starts. When theTG/SG drives the CCD, picture data passes through the A/Dand CDS, and is then input to the ASIC as 12-bit data. TheAF, AE, AWB, shutter, and AGC value are computed from thisdata, and three exposures are made to obtain the optimumpicture. The data which has already been stored in the SDRAMis read by the CPU and color generation is carried out. Eachpixel is interpolated from the surrounding data as being ei-ther R, G and B primary color data to produce R, G and Bdata. At this time, correction of the lens distortion which is acharacteristic of wide-angle lenses is carried out. After AWBand γ processing are carried out, a matrix is generated andaperture correction is carried out for the Y signal, and thedata is then compressed by the JPEG method by (JPEG) andis then written to card memory (SD card).When the data is to be output to an external device, it is takendata from the memory and output via the USB. When playedback on the LCD and monitor, data is transferred from memeryto the SDRAM, and the data elongated by JPEG decorder isdisplayed over the SDRAM display area.3. LCD BlockLCD block is in the CP1 board, and it is constructed by VCOMgeneration circuit etc. The video signal from the ASIC are 8-bit digital signal, and input to LCD directly. It is converted intoRGB signals at driver circuit in the LCD.The VCOM (common polar voltage: AC) and the R, G and Bsignals becomes greater, the display becomes darker; if thedifference in potential is smaller, the element opens and theLCD become brighter. And also the timing pulse except thevideo signal is input to LCD directly from ASIC.4. Lens drive block4-1. Shutter driveThe shutter drive signal (SIN1 and SIN2) which is output fromthe ASIC is drived the shutter constant level driver (IC951),and then shutter is opened and closed.4-2. Iris driveThe iris stepping motor drive signals (IIN1 and IIN2) whichare output from the ASIC (IC101) are used to drive by themotor driver (IC951).4-3. Focus driveThe focus stepping motor drive signals (FIN1, FIN2, FIN3 andFIN4) which are output from the ASIC (IC101) are used todrive by the motor driver (IC951). Detection of the standardfocusing positions is carr ied out by means of thephotointerruptor (AFPI) inside the lens block.4-4. Zoom driveThe zoom DC motor drive signals (ZIN1 and ZIN2) which areoutput from the ASIC (IC101) are used to drive by the motordriver (IC951). Detection of the zoom positions is carried outby means of photoreflector (ZMPI) inside the lens block.