| 摘要 |
A method and apparatus for synchronizing a plurality of signals to a desired signal. The present invention provides real time synchronization of similar audio and any associated sequence of images, either on video or on film, without the need for a separate reference or carrier frequency to be added to both signals. A slave input is synchronized to a master input signal. The slave and master signals are filtered and selected frequencies are analyzed. The resulting output provides signature information about the signals. Thus signature information is digitized into a relatively low number of bits so that comparison of the master and slave signals can be done in real time. In the preferred embodiment of the present invention, three methods of analysis are used on the inputted signals, a bandpass method, a mathematical method and an envelope method. The outputs of the three methods of analysis are inputted to a cross correlation processor which compares the respective analysis outputs for the master and slave inputs. A host computer is utilized for controlling the analysis process, displaying the spectral frame and timing data, and for communicating with the cross-correlator board to determine the amount of speed variation to be done. The computer then outputs a speed control signal, usually to a variable SMPTE generator, which drives a transport control synchronizer to change the speed of the player of the slave signal to keep it in synchronization with the master signal.
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