公开(公告)号：EP0753226A4

公开(公告)日：2000-08-16

申请号：EP95914900

申请日：1995-03-27

申请人： ARBITRON CO

发明人： JENSEN JAMES M ,  LYNCH WENDELL D ,  PERELSHTEYN MICHAEL M ,  GRAYBILL ROBERT B ,  HASSAN SAYED ,  SABIN WAYNE

IPC分类号： H04N5/38 ,  G10L19/00 ,  G11B20/10 ,  H04H20/31 ,  H04H60/13 ,  H04H60/17 ,  H04H60/37 ,  H04H60/40 ,  H04H60/44 ,  H04H60/45 ,  H04H60/58 ,  H04H60/63 ,  H04H60/66 ,  H04M11/06 ,  H04N5/60 ,  H04H9/00 ,  H04N7/08

CPC分类号： H04H20/31 ,  H04H20/14 ,  H04H60/13 ,  H04H60/17 ,  H04H60/37 ,  H04H60/40 ,  H04H60/44 ,  H04H60/45 ,  H04H60/58 ,  H04H60/63 ,  H04H60/66 ,  H04K1/02 ,  H04L27/10 ,  H04L27/30

摘要： Apparatus and methods for including a code (68) having at least one code frequency component in an audio signal (60) are provided. The abilities of various frequency components in the audio signal to mask the code frequency component to human hearing are evaluated (64), and based on these evaluations an amplitude (76) is assigned to the code frequency component. Methods and apparatus for detecting a code in an encoded audio signal are also provided. A code frequency component in the encoded audio signal is detected based on an expected code amplitude or on a noise amplitude within a range of audio frequencies including the frequency of the code component.