Claims
- 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 channel signal on a first carrier frequency signal; modulating the second 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 signal; receiving the composite signal; and separating the first and second stereo channel signals from the composite signal.
- 2. The method of claim 1 further comprising the steps of:
providing the third carrier frequency signal in the 900 MHz frequency band; and providing the first and second carrier frequency signals at frequencies so that the sum and difference of the first and second frequencies with the third carrier frequency remains in the 900 MHz frequency band.
- 3. The method of claim 1 comprising the step of:
detecting a decrease in the signal strength of one of the received, separated, first and second stereo channel signals below a threshold; substituting a received sum signal for the first and second stereo channel signal exhibiting the decrease below the threshold.
- 4. The method of claim 3 further comprising the step of:
separating the sum signal from the composite signal.
- 5. An apparatus for broadcasting first and second stereo channel signals operating according to the method of claim 1.
- 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:
means for forming a sum signal of the first and 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 channel signal on a first carrier frequency signal; means for modulating the second 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 signal; means for receiving the composite signal; and means for separating the first and second stereo channel signals from the composite signal.
- 7. The apparatus of claim 6 further comprising:
means for providing the third carrier frequency signal in the 900 MHz frequency band; and means for providing the first and second carrier frequency signals at frequencies so that the sum and difference of the first and second frequencies with the third carrier frequency remains in the 900 MHz frequency band.
- 8. The apparatus of claim 6 further comprising:
means for detecting a decrease in the signal strength of one of the received, separated, first and second stereo channel signals below a threshold; means for substituting a received sum signal for the first and second stereo channel signal exhibiting the decrease below the threshold.
- 9. The apparatus of claim 8 further comprising:
means for separating the sum signal from the composite signal.
CROSS-REFERENCE TO CO-PENDING APPLICATION
[0001] This application claims the benefit of the priority date of the co-pending U.S. Provisional Application serial No. 60/304,542, filed Jul. 11, 2001, the entire contents of which are incorporated herein in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60304542 |
Jul 2001 |
US |