Patent ID: 7463682

Claim:
A digital signal transmission method, comprising a process of sending and transferring binary signals generated from binary digit signals “0” and “1” from a transmission side to a reception side, wherein, at the transmission side, the binary signals are expressed as a sequence of pulse groups; the binary signals “0” and “1” are expressed by two pulse groups with two special pulse frequencies and with same defined number of pulses and thus with different duration times; and sending the sequence of pulse groups to a medium; wherein, at the reception side, the sequence of pulse groups is received and divided according to the same defined number; the duration times of the pulse groups in the sequence of pulse groups are measured and the duration time differences of the pulse groups are used to express binary digits “0” and “1”; wherein a synchronous process is included before sending the sequence of pulse groups for synchronizing the data transmission and reception and correctly dividing the sequence of pulse groups into the pulse groups; and wherein the synchronous process is as follows: a mark number, a pre-selected multi bytes binary number, is sent from the transmission side repeatedly, and a received number is received at the signal reception side; if the received number is not the same as the mark number, one pulse is canceled before next time in comparing the received number with the mark number, until the same number is received.