| 主权项 |
1. In a digital television system including a transmit section having i) a first signal which carries an image which is a television image, ii) a second signal which is a single or multi-channel audio signal and which second signal may be carried by or with the first signal or separately and iii) a plurality of markers, each responsive to at least one characteristic of the audio signal, and associated in time with the image carried by the first signal before the first and second signals and the plurality of markers are conveyed via a transmission channel to arrive at a receive section in delayed form, the receive section including an apparatus for determining the relative timing of the first signal and the second signal at said receive section, said apparatus comprising;
a) delayed marker separator circuitry responsive to a plurality of markers associated with a first signal's delayed television image in digital form and providing a first delayed plurality of markers, b) delayed marker generating circuitry responsive to a second signal's delayed audio and generating a second plurality of delayed markers in response to a plurality of characteristic of said second signal in digital form, which characteristics include at least the relationship between a plurality of energy related amplitude characteristics over differing ranges of frequencies of said second signal, c) relative timing comparison circuitry responsive to corresponding pairs of said first plurality of delayed markers of a) and said second plurality of delayed markers of b) thereby indicating which of said first signal and said second signal arrived earliest at said apparatus, d) wherein each of said circuitry of elements a), b) and c) comprises electronic analog and/or digital hardware. |
