Multiplex communications – Pulse width modulation
Patent
1995-03-14
1998-06-30
Marcelo, Melvin
Multiplex communications
Pulse width modulation
375208, 375238, 4551541, H04H 500
Patent
active
057744521
ABSTRACT:
A method and apparatus encodes and decodes machine readable signals in audio signals for producing humanly perceived audio transmissions. The encoding device includes circuitry for identifying portions of the audio signal having relatively low energy in a given band and relatively high energy in a band proximally below the given band. The machine readable signals are then inserted into the identified portions of the audio signal. According to another embodiment, the machine readable signals are encoded as a spread-spectrum signal which is added to the original audio signal. The spread-spectrum signal is scaled using a unique technique referred to as Common Mode Scaling.
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Aris Technologies, Inc.
Marcelo Melvin
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