AV timing measurement and correction for digital television

摘要

An invention for measuring, maintaining and correcting synchronization between signals which suffer varying relative delays during transmission and/or storage is shown. The present invention teaches measuring the relative delay between a plurality of signals which have suffered differing delays due to transmission, storage or other processing. The preferred embodiment of the invention includes the use of a marker which is generated in response to a second signal and combined with a first signal in a manner which ensures that the marker will not be lost in the expected processing of the first signal. Subsequently a first delayed marker is generated in response to the marker associated with or recovered from the first signal, and a second delayed marker is generated from the second signal. The first delayed marker and second delayed marker are compared to determine a measure of the relative timing or delay between said first signal and said second signal at said subsequent time.

主权项

1. An apparatus for generating a first set of markers in response to a relatively undelayed or delayed plurality of channels audio signal which is part of a high definition television program which first set of markers are intended to be utilized with a second set of markers generated in response to a delayed or undelayed version respectively of the audio signal, said apparatus including:
a) an input circuit responsive to a digital audio portion of a high definition television program, said input circuit including combining a plurality of channels of said digital audio portion to provide a first digital output signal capable of carrying energy in a range of audio frequencies; b) an input filter circuit comprised of at least two digital filters, each responsive to said first digital output signal, each having a different amplitude response characteristic and each operative to provide a digital filter output signal having an amplitude which is responsive to one or more characteristic of said digital output signal; c) a marker generator circuit responsive to said digital filter output signals and in response thereto generating a sequential plurality of first markers wherein the sequence of said sequential plurality of first markers is generated in response to the timing of frames of video of said high definition television program.