TRANSMISSION SYSTEM WITH WIDEBAND VIRTUAL CHANNEL

摘要

A method is described for transmitting signals having a bit-rate higher than the bit rate of the base rate channels in a digital data transmission system normally providing discrete base rate data channels. The method comprises allocating a group of n+l predetermined bit-rate data channels as a virtual channel for the transmission of the high bit-rate signals. One of the n+l channels is designated as an overhead channel and the remaining n channels are designated as data channels. The high bit-rate signals are divided into n sub-signals having a bit-rate equal to or less than the predetermined bit-rate, and transmitted over the n data channels. Delay calibration signals are transmitted at intervals over the overhead and data channels, the delay calibration signals being transmitted in the data channels in slots normally allocated for data, said data slots being transmitted over said overhead channel while the calibration signals are transmitted in their place. At the far end the delay calibration signals are used to reassemble the n subsignals into the original high bit-rate data signal.