1991-12-17
1994-06-07
Knepper, David D.
G10L 300
Patent
active
053197356
ABSTRACT:
A code signal representing a sequence of code symbols carrying digital information is generated with the frequency components of the code signal being essentially confined to a preselected signalling band lying within the bandwidth of an audio signal within which the code signal is to be embedded. The audio signal is continuously frequency analyzed over a frequency band encompassing the signalling band and the code signal is dynamically filtered as a function of the analysis thereby to provide a modified code signal with frequency components which are, at each time instant, essentially a preselected small proportion of the levels of the corresponding audio signal frequency components. Accordingly, the modified code signal can be combined with the audio signal to obtain a composite audio signal which is not readily distinguishable from the original audio signal by listening. Furthermore, the digital information can be recovered from the composite audio signal by a procedure which is essentially the compliment of that used to obtain the composite audio signal.
REFERENCES:
patent: 3004104 (1961-10-01), Hembrooke
patent: 4395600 (1983-07-01), Lundy et al.
patent: 4425661 (1984-01-01), Moses et al.
patent: 4593389 (1986-06-01), Wurzburg et al.
patent: 4775901 (1988-10-01), Nakano
patent: 4777529 (1988-10-01), Schultz et al.
patent: 4903301 (1990-02-01), Kondo et al.
patent: 4943973 (1990-07-01), Werner
patent: 4965680 (1990-10-01), Endoh
patent: 4972471 (1990-11-01), Gross et al.
patent: 4979210 (1990-12-01), Nagata et al.
patent: 5212551 (1993-05-01), Conanan
Bergamo Marcos A.
Derr Alan G.
Gish Herbert
Huggins A. W. F.
Peterson Patrick M.
Bolt Beranek and Newman Inc.
Knepper David D.
Pahl Jr. Henry D.
LandOfFree
Embedded signalling does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Embedded signalling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Embedded signalling will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-800066