Patent ID: 7463670

Claim:
An apparatus for encoding a data signal, comprising: a spreading code generator for outputting a spreading code, wherein the spreading code contains a direct current (DC) component; an encoder coupling to the spreading code generator, for encoding the spreading code and outputting an encoded spreading code, wherein the encoded spreading code is a first DC-balanced signal; and a spreader coupled to the encoder, for spreading the data signal according to the encoded spreading code, and outputting an output transmission signal to be transmitted through a communications medium to a receiver, wherein the output transmission signal is a second DC-balanced signal, wherein the spreading code is a Barker code, and the sequence of the Barker code is {1,1,1,0,0,0,1,0,0,1,0}, and wherein the encoded spreading code comprises an encoded Barker code, and the encoded Barker code is obtained by deleting one of the fourth, fifth, sixth, eighth, ninth, or eleventh bits of the Barker code.