DOT CLOCK REPRODUCING DEVICE

• Main Authors: YAMAGATA TAKATSUGU, ABE HIDEKI
• Format: Patent
• Language: English
• Published: 08.01.2004
• Edition: 7
• Subjects: ADVERTISING; ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION; CRYPTOGRAPHY; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DISPLAY; EDUCATION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; SEALS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PROBLEM TO BE SOLVED: To provide a dot clock reproducing device capable of automatically adjusting a dot clock frequency with a high precision. SOLUTION: A dot clock DCK is generated on the basis of a synchronizing signal by a PLL circuit 14, and an inputted video signal is sampled in response to the dot clock DCK to obtain sample values by an A/D converter 11. Sample values are successively received, and a plurality of sample points where sample values are changed like pulses in a one-period width of the dot clock, and absolute values of differences between sample values at adjacent sample points constituting pulse-like change in the one-period width are successively accumulated by an accumulation circuit 24. The phase of the dot clock generated by a dot clock generation circuit is controlled by a control circuit 28 on the basis of a ratio of a minimum value to a maximum value of a plurality of accumulation results obtained at intervals of a prescribed period. As a result, the dot clock is controlled to perform control of high precision. COPYRIGHT: (C)2004,JPO