Pioneer DVL-909 Service Guide - Page 10

DV-505, DVL-909, DV-S9 2. CIRCUIT DESCRIPTIONS FOR DV-S9 AND DV-09 2.1 VIDEO SIGNAL PROCESSING BLOCK 2.1.1 PD0259A Block The major purposes of the PD0259A block are; (1) Frame-correlative cyclic digital noise reduction (2) Horizontal and vertical contour compensation (3) Y/C timing adjustment (4) Frame freezing (1) Frame-Correlative Cyclic Digital Noise Reduction For eight-bit digital video data input to the PD0259A, noise reduction is performed through subtraction between the data and those of the corresponding points 1 frame before, delayed for the subtraction via a 4-bit DRAM by 1 frame. The noise signal detected as a result is sent to a non-linear circuit. If the difference is larger than a specific value, it is regarded as "a change in picture," and no canceling calculation is made. This function is the same as that which has been performed in conventional laser-disc players. The only difference is that the input video signal here is a DVD digital component signal (4:2:2), while it is an LD digital composite signal in conventional laser-disc players. DATA (3) Y/C-timing Adjustment This function changes the output phase of the Y signal with respect to the Cb and Cr signals in units of the 13.5-MHz clock cycle (approx. 74 ns). (4) Frame Freezing In response to a command sent from the system control computer by serial transmission, data for one frame are frozen, and the frozen picture is output. This function is specific to the DV-S9 and is used only for pictureby-picture reversing by jog/shuttle operation or "Slow 1" playback operation. 2.1.2 M65677FP Block The M65677FP block functions as an NTSC encoder that converts digital component signals to analog Y, C, Cb and Cr signals. While our popular models other than the DV-S9 use the built-in encoder in the MB86371 block, an external NTSC encoder is added to the DVS9, as it performs digital processing in the PD0259A block. Non-linear circuit ON/OFF SW 1-frame delay (2) Horizontal and Vertical Contour Compensations For data after digital noise reduction, horizontal and vertical contour compensations are made only for the Y-signal. Horizontal compensation is performed by detecting edge components from the information of the reference picture elements and those that horizontally proceed and succeed by several pixels, and then generating edge-emphasizing components through non-linear processing of the detected components. Vertical compensation is performed by detecting edge components from information on the reference picture elements and those which vertically proceed and succeed by one line, and then generating edgeemphasizing components through non-linear processing of the detected components. These edge-emphasizing components are added to the main-line digital data to achieve contour compensations. In addition to NTSC encoding, the M65677FP also performs: (1) D.EXT(DV-S9)/BLACK LVL(DV-09) (2) C.LEVEL adjustment (1) D.EXT(DV-S9)/BLACK LVL(DV-09) Setup of -7.5 IRE is added to the Y signal. D.EXT(DV-S9)/BLACK LVL(DV-09) processing using analog signals in conventional laser disc players is achieved by using digital signals. (2) C.LEVEL Adjustments The burst level of the C signal can be varied centering around 40 IRE. Therefore, it is performed for the S-connector and CVBS-connector outputs, but not for the color-difference output. This function is also not available if the connected TV receiver has no AGC circuit. 1H Delay 1H Delay Vertical edge generation HPF Non-linear circuit Delay BPF Non-linear circuit Horizontal edge generation 10