Forward error correction coding for hybrid AM in-band on-channel digital audio broadcasting systems
First Claim
1. An AM compatible digital audio broadcasting signal, the signal comprising:
- an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal; and
a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation (CPTCM) including a code mapped to overlapping partitions.
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Abstract
An AM compatible digital audio broadcasting signal comprises an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, and a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions. Time diversity can be included between the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals, and/or between groups of the digitally modulated subcarrier signals. A broadcasting method, and transmitters and receivers and that utilize the signal are also provided.
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Citations
42 Claims
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1. An AM compatible digital audio broadcasting signal, the signal comprising:
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an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal; and
a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation (CPTCM) including a code mapped to overlapping partitions. - View Dependent Claims (2, 3, 4)
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5. A transmitter for broadcasting an AM compatible digital audio broadcasting signal, the transmitter comprising:
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means for producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal;
means for producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions; and
means for broadcasting the analog modulated signal and the plurality of digitally modulated subcarrier signals. - View Dependent Claims (6, 7, 8)
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9. A receiver for receiving an AM compatible digital audio broadcasting signal, the receiver comprising:
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an antenna for receiving a composite signal comprising an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, and a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions; and
means for producing an output in response to the composite signal. - View Dependent Claims (10, 11, 12, 13)
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14. An AM compatible digital audio broadcasting signal, the signal comprising:
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an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal;
a first plurality of subcarrier signals in a first portion of the radio channel and a second plurality of subcarrier signals in a second portion of the radio channel, wherein the first and second pluralities of subcarrier signals are complementary modulated subcarrier signals and have a power spectral density below the analog modulated carrier by a first margin;
a third plurality of subcarrier signals in a third portion of the radio channel and a fourth plurality of subcarrier signals in a fourth portion of the radio channel, wherein the third and fourth pluralities of subcarrier signals are complementary modulated subcarrier signals and have a power spectral density below the analog modulated carrier by a second margin; and
a fifth plurality of subcarrier signals in a fifth portion of the radio channel and a sixth plurality of subcarrier signals in a sixth portion of the radio channel, wherein the fifth and sixth pluralities of subcarrier signals have a power spectral density below the analog modulated carrier by a third margin;
wherein the first, second, third, fourth, fifth and sixth pluralities of subcarrier signals are modulated by one or more digital signals, the first margin is larger than the second margin, and the second margin is larger than the third margin. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A method of broadcasting an AM compatible digital audio broadcasting signal, the method comprising the steps of:
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producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal;
producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation (CPTCM) including a code mapped to overlapping partitions; and
transmitting the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals. - View Dependent Claims (22, 23, 24, 25)
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26. A transmitter for broadcasting an AM compatible digital audio broadcasting signal, the transmitter comprising:
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an analog modulator for producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal;
a digital modulator for producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions; and
an antenna for broadcasting the analog modulated signal and the plurality of digitally modulated subcarrier signals. - View Dependent Claims (27, 28, 29)
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30. A receiver for receiving an AM compatible digital audio broadcasting signal, the receiver comprising:
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an antenna for receiving a composite signal comprising an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, and a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions; and
an output device for producing an output in response to the composite signal. - View Dependent Claims (31, 32, 33, 34)
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35. A method of broadcasting an AM compatible digital audio broadcasting signal, the method comprising the steps of:
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producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal;
producing a first plurality of subcarrier signals in a first portion of the radio channel and a second plurality of subcarrier signals in a second portion of the radio channel, wherein the first and second pluralities of subcarrier signals are complementary modulated subcarrier signals and have a power spectral density below the analog modulated carrier by a first margin;
producing a third plurality of subcarrier signals in a third portion of the radio channel and a fourth plurality of subcarrier signals in a fourth portion of the radio channel, wherein the third and fourth pluralities of subcarrier signals are complementary modulated subcarrier signals and have a power spectral density below the analog modulated carrier by a second margin;
producing a fifth plurality of subcarrier signals in a fifth portion of the radio channel and a sixth plurality of subcarrier signals in a sixth portion of the radio channel, wherein the fifth and sixth pluralities of subcarrier signals have a power spectral density below the analog modulated carrier by a third margin;
wherein the first, second, third, fourth, fifth and sixth pluralities of subcarrier signals are modulated by one or more digital signals, the first margin is larger than the second margin, and the second margin is larger than the third margin; and
transmitting the first, second, third, fourth, fifth and sixth pluralities of subcarrier signals. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42)
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Specification