Patent ID: 7286495

Claim:
A digital subscriber line transmission method for transmitting downstream data from a device on an office side to a device on a subscriber side and upstream data from the device on the subscriber side to the device on the office side over a single line by switching between these data transmissions in time-division fashion, dividing data of one symbol, modulating carrier waves having different frequencies by each item of divided data and frequency-multiplexing the modulated signals, and transmitting the frequency-multiplexed signals in bursts a few symbols at a time, wherein the bursts are contiguous transmit burst symbol sequences, said method comprising the steps of: generating a pilot-tone signal with which synchronous processing of the symbol sequences is executed; making the length of an interval between the contiguous transmit burst symbol sequences, in which no frequency-multiplexed signals are transmitted, a whole-number multiple of the cycle of the pilot-tone signal; and assuring continuity of sample data in the contiguous transmit burst symbol sequences by executing processing of the symbol sequences in sync with the pilot-tone signal.