| 摘要 |
This invention is for a reference generator and demodulator for recovering information which has been phase, modulated on (or encoded on) a carrier. The inventive concepts described herein include a novel reference measurement circuit including a sampler and phase measurement circuit to measure the carrier reference's phase and/or frequency relative to a discrete time sampling phase and frequency, and a demodulator reference signal generator to generate properly phased reference signals for use by the phase demodulator circuit. The invention is particularly useful for decoding chroma difference signals of PAL and NTSC television video signals. It is suited to be implemented in digital form, operating on digitized signals thereby deriving all of the benefits normally expected of digital signal processing, including precision, freedom from drift and freedom from alignment. The invention is also particularly well suited to implementation by integrated circuit.
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