Multibit amplitude and phase modulation transceiver for LAN
First Claim
1. A transceiver for communicating multiple bits per signal element between a plurality of nodes interconnected by a communication medium of a LAN, comprising:
- transmitter means receptive of a multiple bit digital input value originating at the node, and operative for converting the digital input value into an analog signal having an amplitude and a phase which is defined by a predetermined correlation code to the bit pattern of the digital input value, said transmitter means further transmitting the analog signal over the medium to other nodes of the LAN; and
receiver means responsive to each received analog signal transmitted by another node over the medium, and operative for converting the amplitude and phase of the received analog signal into a multiple bit digital output value which has a bit pattern that corresponds to the bit pattern of the digital input value, said receiver means using the predetermined correlation code to make the conversion, said receiver means further comprising;
means receptive of the received analog signal and operative for supplying a primary signal having an amplitude related in a predetermined manner to the amplitude of the received analog signal;
means responsive to the characteristics of the primary signal for generating a sample clock signal which defines the point at which the amplitude of the primary signal is to be converted to the digital output value; and
means responsive to the sample clock signal for converting the amplitude of the primary signal to the digital output value.
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Accused Products
Abstract
A transceiver for a LAN is capable of communicating multiple bits per signal element to increase the data throughput of the LAN. The transceiver includes a transmitter which receives a multiple bit digital input value originating at a node of the LAN at which the transceiver is present. The transmitter converts the multiple bit digital input signal into a pulse-like analog signal which is amplitude and phase modulated. A receiver of a transceiver at a receiving node the transmitted analog signal converts its amplitude and phase into a corresponding multiple bit digital output value. A time-domain filter of the receiver creates a primary signal from the received analog signal. To sample the primary signal at its maximum amplitude point, a derivative of the primary signal waveform is used to establish the zero derivative point at which the primary signal attains its maximum amplitude, and to establish a fixed sampling point for subsequent signals. The sampling point is synchronized in phase with the stream of received analog signals. The residual intersymbol interference (ISI) effect of preceding signals on the LAN medium is eliminated prior to converting the primary signal to the digital value. To adjust and compensate for attenuation and amplification created by the LAN medium, the signal values are normalized.
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Citations
56 Claims
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1. A transceiver for communicating multiple bits per signal element between a plurality of nodes interconnected by a communication medium of a LAN, comprising:
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transmitter means receptive of a multiple bit digital input value originating at the node, and operative for converting the digital input value into an analog signal having an amplitude and a phase which is defined by a predetermined correlation code to the bit pattern of the digital input value, said transmitter means further transmitting the analog signal over the medium to other nodes of the LAN; and receiver means responsive to each received analog signal transmitted by another node over the medium, and operative for converting the amplitude and phase of the received analog signal into a multiple bit digital output value which has a bit pattern that corresponds to the bit pattern of the digital input value, said receiver means using the predetermined correlation code to make the conversion, said receiver means further comprising; means receptive of the received analog signal and operative for supplying a primary signal having an amplitude related in a predetermined manner to the amplitude of the received analog signal; means responsive to the characteristics of the primary signal for generating a sample clock signal which defines the point at which the amplitude of the primary signal is to be converted to the digital output value; and means responsive to the sample clock signal for converting the amplitude of the primary signal to the digital output value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A transceiver for communicating multiple bits per signal element between a plurality of nodes interconnected by a communication medium of a LAN, comprising:
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transmitter means receptive of a multiple bit digital input value originating at the node, and operative for converting the digital input value into an analog signal having an amplitude and a phase which is defined by a predetermined correlation code to the bit pattern of the digital input value, said transmitter means further transmitting the analog signal over the medium to other nodes of the LAN; and receiver means responsive to each received analog signal transmitted by another node over the medium, and operative for converting the amplitude and phase of the received analog signal into a multiple bit digital output value which has a bit pattern that corresponds to the bit pattern of the digital input value, said receiver means using the predetermined correlation code to make the conversion, said receiver means further comprising; means receptive of the received analog signal and operative for creating a derivative waveform corresponding to the mathematical derivative of the waveform of the analog signal; means for supplying a derivative waveform which is a mathematical derivative of the primary signal; means for converting the amplitude of the analog signal into a digital value; and means responsive to the derivative waveform for establishing the point at which the converting means converts the amplitude of the analog signal into the digital value. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 41)
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33. A transceiver for communicating multiple bits per signal element between a plurality of nodes interconnected by a communication medium of a LAN, comprising:
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transmitter means receptive of a multiple bit digital input value originating at the node, and operative for converting the digital input value into an analog signal having an amplitude and a phase which is defined by a predetermined correlation code to the bit pattern of the digital input value, said transmitter means further transmitting the analog signal over the medium to other nodes of the LAN; and receiver means responsive to each received analog signal transmitted by another node over the medium, and operative for converting the amplitude and phase of the received analog signal into a multiple bit digital output value which has a bit pattern that corresponds to the bit pattern of the digital input value, said receiver means using the predetermined correlation code to make the conversion;
said receiver means further comprising;means for determining the amount of residual signal effect created by one preceding received analog signal which is periodically inserted by the transmitter means in a stream of analog signals transmitted; and means for eliminating the residual signal effect during the conversion of each of a plurality of subsequently received analog signals to the digital output value, based on the amount of residual signal effect determined from said one analog signal. - View Dependent Claims (34, 35, 36)
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37. A transceiver for communicating multiple bits per signal element between a plurality of nodes interconnected by a communication medium of a LAN, comprising:
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transmitter means receptive of a multiple bit digital input value originating at the node, and operative for converting the digital input value into an analog signal having an amplitude and a phase which is defined by a predetermined correlation code to the bit pattern of the digital input value, said transmitter means further transmitting the analog signal over the medium to other nodes of the LAN; and receiver means responsive to each received analog signal transmitted by another node over the medium, and operative for converting the amplitude and phase of the received analog signal into a multiple bit digital output value which has a bit pattern that corresponds to the bit pattern of the digital input value, said receiver means using the predetermined correlation code to make the conversion, said receiver means further comprising; means for supplying a normalized value representative of the received analog signal relative to a predetermined value representative of the signal attenuation or signal amplification by the medium between a transmitting node and a receiving node. - View Dependent Claims (38)
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39. A transceiver for communicating multiple bits per signal element between a plurality of nodes interconnected by a communication medium of a LAN, comprising:
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transmitter means receptive of a multiple bit digital input value originating at the node, and operative for converting the digital input value into an analog signal having an amplitude and a phase which is defined by a predetermined correlation code to the bit pattern of the digital input value, said transmitter means further transmitting the analog signal over the medium to other nodes of the LAN; and receiver means responsive to each received analog signal transmitted by another node over the medium, and operative for converting the amplitude and phase of the received analog signal into a multiple bit digital output value which has a bit pattern that corresponds to the bit pattern of the digital input value, said receiver means using the predetermined correlation code to make the conversion, said receiver means further comprising; time-domain filter means receptive of the received analog signal and operative for supplying a primary signal having an amplitude related in a predetermined manner to the amplitude of the received analog signal. - View Dependent Claims (40, 42, 43)
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44. A transceiver for transmitting and receiving amplitude modulated analog signals occurring at a predetermined transmit frequency on a communication medium which interconnects a plurality of nodes of a LAN, at least some of the analog signals transmitted being calibration signals having a predetermined amplitude, the calibration signals having periodically inserted in a stream of data analog signals, said transceiver comprising an improved receiver means for receiving analog signals from the medium, comprising:
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means responsive to the calibration signal received from the medium and operative for generating an asynchronous signal occurring in a predetermined time relationship to the calibration signal, the synchronous signal generating means generating the asynchronous signal in response to a predetermined analog characteristic of a single received calibration signal; synchronizer means responsive to the asynchronous signal and operative for supplying a sample clock signal substantially at the predetermined transmit frequency and in a substantially fixed phase relationship relative to the received analog signals, the synchronizer means establishing the fixed phase relationship in response to the asynchronous signal; and conversion means responsive to the sample clock signal for sampling the amplitude of a signal relative to the received analog signal at a point established by the sample clock signal. - View Dependent Claims (45, 46, 47, 48, 49, 50)
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51. A transceiver for transmitting and receiving amplitude modulated analog signals occurring at a predetermined transmit frequency on a communication medium which interconnects a plurality of nodes of a LAN, at least some of the analog signals transmitted being calibration signals having a predetermined amplitude, the calibration signals being periodically inserted in a stream of data analog signals, said transceiver comprising an improved receiver means for receiving analog signals from the medium, comprising:
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means responsive to the received calibration signal for generating an asynchronous signal in a predetermined relationship to the calibration signal; synchronizer means responsive to the asynchronous signal and operative for supplying a sample clock signal substantially at the predetermined transmit frequency and in a substantially fixed phase relationship relative to the received analog signals, the synchronizer means establishing the fixed phase relationship in response to the asynchronous signal; and conversion means responsive to the sample clock signal for sampling the amplitude of a signal related to the received analog signal at a point established by the sample clock signal; and
wherein;said conversion means responds to the sample clock signal to convert the maximum amplitude and phase of a primary signal representative of each received analog signal into an initial digital value; and
further comprising;adjusting means responsive to the sample clock signal for adjusting the initial digital value to a different digital output value by substantially eliminating the effect of gain or attenuation from the medium. - View Dependent Claims (52, 53)
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54. A transceiver for transmitting and receiving amplitude modulated analog signals occurring at a predetermined transmit frequency on a communication medium which interconnects a plurality of nodes of a LAN, at least some of the analog signals transmitted being calibration signals having a predetermined amplitude, the calibration signals being periodically inserted in a stream of data analog signals, said transceiver comprising an improved receiver means for receiving analog signals from the medium, comprising:
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means responsive to the received calibration signal for generating an asynchronous signal in a predetermined relationship to the calibration signal; synchronizer means responsive to the asynchronous signal and operative for supplying a sample clock signal substantially at the predetermined transmit frequency and in a substantially fixed phase relationship relative to the received analog signals, the synchronizer means establishing the fixed phase relationship in response to the asynchronous signal; conversion means responsive to the sample clock signal for sampling the amplitude of a signal related to the received analog signal at a point established by the sample clock signal; conversion means responsive to the sample clock signal for converting the maximum amplitude and phase of each received analog signal into an initial digital value; and adjusting means responsive to the sample clock signal for adjusting the initial digital value to a different digital output value by substantially eliminating the effect of intersymbol interference (ISI). - View Dependent Claims (55, 56)
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Specification