Patent ID: 7099379

Claim:
A method for encoding and extracting a second signal within the transmission of a television video signal comprising the steps of: providing a television video signal; providing said second signal; modulating said second signal utilizing a spread spectrum technique to form a code modulated signal; modulating a carrier signal with said television video signal and said code modulated signal; transmitting said modulated carrier signal; receiving said modulated carrier signal; demodulating said transmitted carrier signal to recover a combination signal including said television video signal and said code modulated signal; and recovering said second signal from said combination signal by despreading said combination signal; wherein the demodulating and recovering steps further comprise the step of synchronizing a reference code used to modulate said second signal with the received modulated carrier signal, comprising the steps of: providing a reference code signal reversing the order of bits in said reference code signal to produce a reversed code signal; performing a transform on said reversed code signal to produce a transformed reversed code signal; performing said transform on said received signal to produce a transformed received signal; processing said transformed reversed code signal and said transformed received signal to produce an intermediate signal; performing an inverse of said transform on said intermediate signal to produce a correlation signal; determining a peak value in said correlation signal; determining a wait value from said peak value, said wait value indicating a time period to wait while receiving said received signal so that said embedded code of said received signal substantially aligns with said reference code signal; and waiting for said time period while receiving said received signal to synchronize the embedded reference code in said received signal with said reference code signal.