| 摘要 |
PURPOSE:To make the titled device with comparatively small scale suitable for any broadcast system by using a reference clock being an integral number of multiple of a horizontal synchronizing frequency to apply A/D conversion directly to a video signal and multiplying chrominance carrier signal digital data by subcarrier digital data. CONSTITUTION:A a reference clock being an integral number of multiple of a horizontal synchronizing frequency fH is used to apply direct A/D conversion to an analog video signal and reference sine wave data for subcarrier is stored in memories 1, 2. DATA 10 from the memory 1 and DATA 11 from a phase inverter are fed to a control circuit CNT. The control circuit CNT supplies SIN wave data in matching with each system to a multiplier 1 as a phase comparison reference signal DATA 12. DATA 1, 10 and the DATA 11 are multiplied respectively by multipliers 2, 3 to apply phase detection and to output DATA 14, 15. The data are converted into a digital color difference signal by digital LPFs 2, 3 to form DATA 16, 17. Thus, the titled device is applied to any system without being limited by the chrominance subcarrier frequency fSC.
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