Patent ID: 6510183
Filing Date: 2003-01-21
Classification: G11B,H04B,H04N

Abstract:
A method of superimposing and of detecting an additional information signal comprising the steps of:producing a first code synchronized with a synchronous signal included in a main information signal; producing a low-level wide band additional information signal from said additional information signal using said first code; producing a superimposed main information signal by superimposing said low-level wide-band additional information signal on said main information signal; producing a second code equal to said first code synchronized with said synchronous signal included in said superimposed main information signal; obtaining an accumulated value by sequentially adding a sample value of said superimposed main information signal to said accumulated value when a corresponding chip value of said second code is a first predetermined value, and sequentially subtracting said sample value of said superimposed main information signal from said accumulated value when said corresponding chip value of said second code is a second predetermined value for all chips of said second code until said accumulated value is greater or equal to a threshold value; and detecting said additional information signal in said superimposed main information signal by determining whether said accumulated value has exceeded said threshold value.