| 摘要 |
<p>PURPOSE: A system is provided for the transmission of data representing a video image and for transmission over an analogue transmission link. CONSTITUTION: A transmitter having means to encode an input signal to form coded data, each element of said coded data having one of at least two discrete signal magnitude levels, the encoding means including in the coded data a periodic training sequence of data; and a receiver to receive the coded data and, on the basis of the received training sequence, to adapt a threshold or thresholds to allow the discrete levels to be distinguishable from each other are comprised. The receiver is continually allowed to adapt the threshold(s) in dependence on the dynamic conditions of the transmission link between the transmitter and receiver. The training sequence comprises at least two elements, the receiver including means to monitor the effect of at least one of the elements of the training sequence on another of said elements of the training sequence and adapt the threshold(s) accordingly. The receiver generates a look-up-table to store the adapted thresholds.</p> |
