Multiple signal carrier transmission apparatus and method
First Claim
1. A method of transmitting discrete first and second stereo channel signals from a signal source to a receiver for broadcast as first and second stereo channels, the method comprising the steps of:
- forming a sum signal of the first and second stereo channel signals;
forming a difference signal of the first and second stereo channel signals;
developing a first stereo channel signal and a second stereo channel signal from the sum and difference signals;
modulating the first stereo channel signal on a first carrier frequency signal;
modulating the second stereo channel signal on a second carrier frequency signal;
modulating the sum signal on a third carrier frequency signal;
combining the first, second and sum modulated signals and the first, second and third carrier frequency signals to form a composite modulated carrier signal;
transmitting the composite modulated carrier signal;
receiving the composite modulated carrier signal; and
separating the first and second stereo channel signals from the composite modulated carrier signal.
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Accused Products
Abstract
A multiple signal carrier transmission apparatus and method for broadcasting stereo sounds to an audio output device uses three related carrier frequencies on which are modulated the sum of first and second stereo channel signals and the first and second stereo channel signals themselves. The composite multiple carrier frequency signal is transmitted to a receiver which separates the three carrier frequency signals to generate a separate left channel signal, a right channel signal and a composite center channel, monophonic, signal which is the sum of the first and second channel signals. A detector monitors the signal strength of each separate left and right channel signal to detect a decrease in either channel output below a threshold. When a decrease below the threshold is detected, the center sum signal replaces the left and/or right channel signal having the diminished signal strength for output through the appropriate speaker to minimize channel fade out.
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Citations
9 Claims
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1. A method of transmitting discrete first and second stereo channel signals from a signal source to a receiver for broadcast as first and second stereo channels, the method comprising the steps of:
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forming a sum signal of the first and second stereo channel signals;
forming a difference signal of the first and second stereo channel signals;
developing a first stereo channel signal and a second stereo channel signal from the sum and difference signals;
modulating the first stereo channel signal on a first carrier frequency signal;
modulating the second stereo channel signal on a second carrier frequency signal;
modulating the sum signal on a third carrier frequency signal;
combining the first, second and sum modulated signals and the first, second and third carrier frequency signals to form a composite modulated carrier signal;
transmitting the composite modulated carrier signal;
receiving the composite modulated carrier signal; and
separating the first and second stereo channel signals from the composite modulated carrier signal. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for broadcasting first and second stereo channels from a signal source to a receiver for broadcast as first and second channels, the apparatus comprising:
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means for forming a sum signal of a first and a second stereo channel signals;
means for forming a difference signal of the first and second stereo channel signals;
means for developing a first stereo channel signal and a second stereo channel signal from the sum and difference signals;
means for modulating the first stereo channel signal on a first carrier frequency signal;
means for modulating the second stereo channel signal on a second carrier frequency signal;
means for modulating the sum signal on a third carrier frequency signal;
means for combining the first, second and sum modulated signals and the first, second and third carrier frequency signals to form a composite modulated carrier signal;
means for transmitting the composite modulated carrier signal;
means for receiving the composite modulated carrier signal; and
means for separating the first and second stereo channel signals from the composite modulated carrier signal. - View Dependent Claims (7, 8, 9)
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Specification