Method and apparatus for producing high-fidelity images by synchronous phase coherent digital image acquisition

摘要

An apparatus and method for synchronizing sampling of a video signal to a video synchronization signal of the video signal are provided. The frequency-divided output of an oscillator (or other controllable frequency source) is applied as one input to a phase detector, while the other input to the phase detector is supplied by the video synchronizing signals. The error signal voltage output of the phase detector is applied to correct the frequency, and thereby the phase, of the oscillator output through a dynamically-tuned phase-locked loop filter until the phases of the two input signals are in perfect agreement and no error voltage is produced. After a delay for this phase correction, during which time all video amplification is suspended, an output of the oscillator is then applied to sample the image without the presence of phase disparities while video amplification is restored. Full dynamic range digital acquisition then proceeds with extremely high accuracy at any desired resolution. An apparatus and method are provided for achieving such operation.