Method and system for FM stereo broadcasting
First Claim
1. A method for broadcasting two different audio programs to a frequency modulated (FM) channel, comprising:
- broadcasting a first audio program and a second audio program on an FM carrier, where the first audio program is distinct from the second audio program; and
demodulating the FM carrier to produce stereo audio with a left and a right channel where the first audio program is channeled to the left channel and the second audio program is channeled to the right channel.
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Abstract
This invention provides a system capable of transmitting two different audio programs in one FM channel signal and generate either one of the audio programs through an FM receiver, such as an FM radio or stereo playback device using pre-recorded media. To accomplish this, one program may be transmitted through the left channel of the FM channel signal and a different program in the right channel of the FM channel signal. A switching circuit may be provided either internally or externally for an FM receiver, headset or speakers that can switch between the “left” and “right” audio programs in the FM channel signal so that a listener may select from either audio programs within one FM channel signal.
119 Citations
31 Claims
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1. A method for broadcasting two different audio programs to a frequency modulated (FM) channel, comprising:
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broadcasting a first audio program and a second audio program on an FM carrier, where the first audio program is distinct from the second audio program; and
demodulating the FM carrier to produce stereo audio with a left and a right channel where the first audio program is channeled to the left channel and the second audio program is channeled to the right channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for broadcasting two different audio programs to a frequency modulated (FM) channel, comprising:
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providing a main carrier signal with an associated sub-carrier signal;
providing a first audio program signal and a separate second audio program signal;
providing a pilot tone;
adding the first audio program signal plus the second audio program signal to produce an added signal;
modulating the first audio program signal minus the second audio program signal onto the sub-carrier to produce sidebands;
adding the pilot tone, the sidebands, and the added signal to form a composite signal;
frequency modulating the main carrier signal with the composite signal to produce a composite frequency modulated signal; and
transmitting the composite frequency modulated signal.
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10. A method for broadcasting two different audio programs to an FM channel, comprising:
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providing a first audio program having a first time slot associated with a first program;
providing a second audio program having a second time slot associated with a second program, where the first program is distinct from the second program;
converting the first audio program into a first audio program signal;
converting the second audio program into a second audio program signal; and
transmitting the first and second audio programs through left and right channels of an frequency modulated (FM) channel. - View Dependent Claims (11, 12, 13, 16, 17, 18, 19, 20, 21)
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14. A method for broadcasting two different audio programs to an FM channel, comprising:
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providing a first audio program having a first sub-program that plays at a predetermined time and a first intermediate program which plays at an intermediate time;
providing a second audio program having a second sub-program, distinct from the first audio program that plays at the predetermined time and a second intermediate program which plays at the intermediate time, where the first and second intermediate programs are substantially identical;
converting the first audio program into a first audio program signal;
converting the second audio program into a second audio program signal;
providing a main carrier signal with an associated sub-carrier signal;
providing a pilot tone;
adding the first audio program signal plus the second audio program signal to produce an added signal;
modulating the first audio program signal minus the second audio program signal onto the sub-carrier to produce sidebands;
adding the pilot tone, the sidebands, and the added signal to form a composite signal;
frequency modulating the main carrier signal with the composite signal to produce a composite frequency modulated signal; and
transmitting the composite frequency modulated signal.
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15. An apparatus capable of broadcasting different audio programs to an FM channel, comprising:
a switching circuit having a master switch capable of coupling left and right input terminals to left and right output terminals, where the left and right input terminals are adapted to couple to outputs from left and right channel pre-amplifiers of an FM receiver, respectively, and the left and right output terminals are adapted to left and right speakers, respectively.
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22. A method for producing two different audio programs from one FM channel, comprising:
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broadcasting a first audio program through a left channel in an FM carrier and a second audio program that is distinct from the first audio program through the FM carrier;
receiving the first and second audio programs in the FM carrier; and
generating the first or second audio program from the FM carrier. - View Dependent Claims (23, 25, 26, 27, 29, 30, 31)
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24. A system for providing two different audio programs from one FM channel, comprising:
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a broadcaster transmitting a first audio program and a second audio program through an FM carrier, where the first and second audio programs are distinct from each other; and
a receiver adapted to receive the FM carrier to produce stereo audio with a left channel and a right channel, where the first audio program is channeled to the left channel and the second audio program is channeled to the right channel.
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28. A system for providing two different audio programs from one FM channel, comprising:
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means for broadcasting two distinct audio programs within a certain area;
means for receiving the two distinct audio programs; and
means for selecting between the two distinct audio programs and playing at least one of the two distinct audio programs to a listener.
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Specification