EP0366381A2
Expired / Lapsed
EP
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Signal identification system
Assignee: Central Research Laboratories Ltd
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Filing: 1989-10-23
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Granted: —
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Expires: 2009-10-23
Abstract
Abstract A signal identification system, suitable for producing an identification code on a sound track recording is described. The system includes an encoder 209 effective to eliminate a variable sequence of frequency bands from an audio signal and insert a sequence of code signals into the frequency bands. As the sequence of frequency bands varies throughout the sound track recording, the presence of the code is difficult to detect.
Inventors
- 👤 Stuart John Best
- 👤 Nigel Johnson
- 👤 Adrian Miles Sandford
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 03:49
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/28; H04H20/30; H04H20/31; G; G11; G11B; G11B20/00; G11B20/00086; G11B20/00884; G11B20/00891
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
101 words
A signal identification system comprising: encoding means comprising means for choosing a variable sequence of frequency bands from a plurality of different predetermined frequency bands in the bandwidth of a given signal; means for eliminating the sequence of chosen frequency bands from the given signal to form a sequence of corresponding notches in the given signal; and means for inserting a sequence of code signals into the notches, each code signal comprising frequencies within the bandwidth of the notch or notches into which it is inserted; and decoding means for determining whether the code signal is present in the given signal.
Claim 2
Dependent Claim
101 words
A signal identification system comprising: encoding means comprising means for choosing a variable sequence of frequency bands from a plurality of different predetermined frequency bands in the bandwidth of a given signal; means for eliminating the sequence of chosen frequency bands from the given signal to form a sequence of corresponding notches in the given signal; and means for inserting a sequence of code signals into the notches, each code signal comprising frequencies within the bandwidth of the notch or notches into which it is inserted; and decoding means for determining whether the code signal is present in the given signal.
Claim 3
Dependent Claim
28 words
A system according to Claim 1 in which there are at least three different predetermined frequency bands, each code signal comprising frequencies within two different predetermined frequency bands.
Claim 4
Dependent Claim
25 words
A system according to Claim 2 in which the code signals within each of the two different predetermined frequency values represent respective different binary values.
Claim 5
Independent Claim
31 words
A system according to anyone of the preceding claims in which the decoding system includes means for inspecting all possible combinations of the predetermined frequency bands in a signal substantially simultaneously.
Claim 6
Independent Claim
38 words
A system according to any one of Claims 1 to 4 in which the variable sequence is a predetermined sequence and the decoding system includes means for inspecting predetermined frequency bands in the order of the predetermined sequence.
Claim 7
Dependent Claim
89 words
An encoding system for the coding of a given signal comprising: means for choosing a variable sequence of frequency bands from a plurality of different predetermined frequency bands in the bandwidth of a given signal; means for eliminating the sequence of chosen frequency bands from the given signal to form a sequence of corresponding notches in the given signal; and means for inserting a sequence of code signals into the notches, each code signal comprising frequencies within the bandwidth of the notch or notches into which it is inserted.
Claim 8
Dependent Claim
89 words
An encoding system for the coding of a given signal comprising: means for choosing a variable sequence of frequency bands from a plurality of different predetermined frequency bands in the bandwidth of a given signal; means for eliminating the sequence of chosen frequency bands from the given signal to form a sequence of corresponding notches in the given signal; and means for inserting a sequence of code signals into the notches, each code signal comprising frequencies within the bandwidth of the notch or notches into which it is inserted.
Claim 9
Dependent Claim
28 words
A system according to Claim 6 in which there are at least three different predetermined frequency bands, each code signal comprising frequencies within two different predetermined frequency bands.
Claim 10
Dependent Claim
25 words
A system according to Claim 7 in which the code signals within each of the two different predetermined frequency values represent respective different binary values.
Claim 11
Independent Claim
39 words
A system according to any one of claims 6 to 8 in which the encoding means includes means for inhibiting the insertion of the code signal into the notches where the code signal is not likely to be detectable.
Claim 12
Dependent Claim
42 words
A decoding system for decoding a signal in which a code signal has been incorporated in a variable sequence of predetermined frequency bands in the signal, the decoding system including means for inspecting a plurality of combinations of the predetermined frequency bands.
Claim 13
Dependent Claim
42 words
A decoding system for decoding a signal in which a code signal has been incorporated in a variable sequence of predetermined frequency bands in the signal, the decoding system including means for inspecting a plurality of combinations of the predetermined frequency bands.
References Cited (Backward Citations)
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