Simultaneous analog and digital communication
First Claim
1. A modem comprising:
- a first mapper responsive to a digital signal,a second mapper responsive to an analog signal,an orthogonal modulator concurrently responsive to output signals of the first mapper added to output signals of the second mapper to develop an output signal,a hybrid having a first port that receives the output signal developed by the orthogonal modulator, said hybrid communicating substantially all of the signals received at the first port to a second port of the hybrid,an echo canceller coupled to a third port of the hybrid, for subtracting from the third port a portion of the signal applied to said first port of the hybrid,a demodulator responsive to output signals of the echo canceller,a slicer for detecting digital signal components contained in output signals developed by the demodulator,a first de-mapper for forming a stream of digital signals in response to output signals of the slicer,means for subtracting the detected digital signal components from the signals developed by the demodulator, to develop thereby component analog signals, anda second de-mapper for forming analog signal from output signals of the means for subtracting.
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Accused Products
Abstract
A method and apparatus for concurrent communication of analog information and digital information. In general terms, when the communication channel is viewed as a multi-dimensional space, the digital information signal is divided into symbols, and the symbols are mapped onto the signal space with a preset distance between them. The analog signal, generally limited in magnitude to less than the distance separating the symbols, is converted to component signals and added (i.e., vector addition) to the symbols. The sum signal is then transmitted to the receiver where the symbols are detected and subtracted from the received signal to yield the analog signal components. The transmitted analog signal is recreated from those components. Both half-duplex and full-duplex operation is available in accordance with the disclosure.
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Citations
11 Claims
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1. A modem comprising:
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a first mapper responsive to a digital signal, a second mapper responsive to an analog signal, an orthogonal modulator concurrently responsive to output signals of the first mapper added to output signals of the second mapper to develop an output signal, a hybrid having a first port that receives the output signal developed by the orthogonal modulator, said hybrid communicating substantially all of the signals received at the first port to a second port of the hybrid, an echo canceller coupled to a third port of the hybrid, for subtracting from the third port a portion of the signal applied to said first port of the hybrid, a demodulator responsive to output signals of the echo canceller, a slicer for detecting digital signal components contained in output signals developed by the demodulator, a first de-mapper for forming a stream of digital signals in response to output signals of the slicer, means for subtracting the detected digital signal components from the signals developed by the demodulator, to develop thereby component analog signals, and a second de-mapper for forming analog signal from output signals of the means for subtracting. - View Dependent Claims (2, 3, 4, 5)
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6. In a system including a signal space mapper followed by a modulator, where a digital input symbol applied to the mapper is assigned to a constellation point in N-dimension space, and where the modulator modulates the constellation point with N mutually orthogonal carrier signals, an improvement comprises:
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an analog port included in the mapper, for accepting a group of N analog signal samples, said mapper including means for altering the constellation point assignment for the digital input symbol in response to the group of N analog signal samples; and a processor coupled to said analog port for receiving an analog signal and for developing said group of N analog signal samples, wherein said processor encodes said analog signal to develop an encoded signal having a dynamic range that is smaller than the dynamic range of the analog signal. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification