US5050189A — Multibit amplitude and phase modulation transceiv…

Claim 1

Independent Claim 245 words

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.

Claim 2

Dependent Claim 245 words

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.

Claim 3

Dependent Claim 69 words

A transceiver as defined in claim 1 wherein said sample clock signal generating means further comprises: means for creating a derivative waveform corresponding to the mathematical derivative of the waveform of the primary signal; zero detection means responsive to the derivative waveform for supplying a zero crossing signal whenever the derivative waveform is approximately zero; and means responsive to the zero crossing signal for establishing the sample clock signal.

Claim 4

Dependent Claim 50 words

A transceiver as defined in claim 2 wherein said means receptive of the received analog signal further comprises: 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.

Claim 5

Dependent Claim 57 words

A transceiver as defined in claim 3 wherein: the transmitter means transmits each analog signal as a pulse analog signal having predetermined time-domain characteristics; and the time-domain filter means produces a maximum output energy in correspondence to a received pulse analog signal having the predetermined time-domain characteristics and substantially attenuates signals from the medium of other characteristics.

Claim 6

Dependent Claim 26 words

A transceiver as defined in claim 2 wherein the primary signals on the communication medium are each substantially in the form of a sine pulse waveform.

Claim 7

Dependent Claim 78 words

A transceiver as defined in claim 2 wherein said sample clock signal generating means further comprises: threshold detector means responsive to the amplitude of the primary signal and operative for supplying a threshold signal whenever the amplitude of the primary signal exceeds a predetermined threshold value; means for supplying an asynchronous signal upon the simultaneous occurrence of the zero crossing and threshold signals; and synchronizing means for establishing the sample clock signal in response to the asynchronous signal.

Claim 8

Dependent Claim 54 words

A transceiver as defined in claim 6 wherein said transmitter means transmits the analog signals over the medium at a predetermined transmit frequency, and wherein: said synchronizer means supplies the sample clock signal at a frequency which substantially corresponds to the transmit frequency and in a predetermined fixed phase relationship with the primary signals.

Claim 9

Dependent Claim 23 words

A transceiver as defined in claim 7 wherein said synchronizer means establishes the fixed phase relationship in response to a single calibration signal.

Claim 10

Dependent Claim 51 words

A transceiver as defined in claim 7 wherein the one analog signal which establishes the sample clock signal comprises: a calibration signal which is periodically inserted in a serial stream of analog signals transmitted by the transmitter means; and each calibration signal is of a predetermined amplitude and a predetermined phase.

Claim 11

Dependent Claim 104 words

A transceiver as defined in claim 9 wherein each calibration signal is immediately preceded and immediately followed by an interval of silence wherein no analog signal is transmitted, and said receiver means further comprises: means responsive to the calibration signal for determining the amount of residual signal remaining on the medium during the immediately following interval of silence, the residual signal being an intersymbol interference (ISI) effect created by and related by a predetermined fraction to the preceding calibration signal; and means for eliminating the ISI effect during the conversion of each analog signal into the corresponding digital output value of the analog signal.

Claim 12

Dependent Claim 71 words

A transceiver as defined in claim 10 wherein: the ISI effect is a fractional value established by amplitude of the residual signal in the interval following the calibration signal relative to the amplitude of the calibration signal; and said ISI effect elimination means multiplies the ISI fractional value and a value representative of the preceding converted analog signal to establish the amount of ISI effect on a currently received analog signal.

Claim 13

Dependent Claim 36 words

A transceiver as defined in claim 11 wherein: said ISI elimination means further subtracts the amount of the ISI effect from a value representative of a current received analog signal to supply an ISI compensated value.

Claim 14

Dependent Claim 37 words

A transceiver as defined in claim 12 wherein said receiver means further comprises: means for adjusting the gain of the receiver means to compensate for the effects of signal attenuation or signal amplification by the communication medium.

Claim 15

Dependent Claim 46 words

A transceiver as defined in claim 13 wherein said gain adjusting means comprises: means for supplying a normalized value representative of the ISI compensated value relative to a value representative of the full amplitude of the calibration signal, the normalized value establishing the digital output value.

Claim 16

Dependent Claim 32 words

A transceiver as defined in claim 14 wherein: said means for supplying a normalized value operatively divides the ISI compensated value by a value representative of the amplitude of the calibration signal.

Claim 17

Dependent Claim 33 words

A transceiver as defined in claim 15 wherein said receiver means further comprises: thresholding means receptive of the normalized value and operative for classifying any fractional normalized value into the digital output value.

Claim 18

Dependent Claim 29 words

A transceiver as defined in claim 16 wherein the analog signals and the calibration signal on the communication medium are substantially in the form of a sine pulse waveform.

Claim 19

Dependent Claim 239 words

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 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.

Claim 20

Dependent Claim 239 words

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 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.

Claim 21

Dependent Claim 26 words

A transceiver as defined in claim 18 wherein the analog signals on the communication medium are each substantially in the form of a sine pulse waveform.

Claim 22

Dependent Claim 141 words

A transceiver as defined in claim 18 where said receiver means further comprises: 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; and 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, said sample clock signal generating means further comprising: means for creating a derivative waveform corresponding to the mathematical derivative of the waveform of the primary signal; zero detection means responsive to the derivative waveform for supplying a zero crossing signal whenever the derivative waveform is approximately zero; and means responsive to the zero crossing signal for establishing the sample clock signal.

Claim 23

Dependent Claim 78 words

A transceiver as defined in claim 20 wherein said sample clock signal generating means further comprises: threshold detector means responsive to the amplitude of the primary signal and operative for supplying a threshold signal whenever the amplitude of the primary signal exceeds a predetermined threshold value; means for supplying an asynchronous signal upon the simultaneous occurrence of the zero crossing and threshold signals; and synchronizing means for establishing the sample clock signal in response to the asynchronous signal.

Claim 24

Dependent Claim 54 words

A transceiver as defined in claim 21 wherein said transmitter means transmits the analog signals over the medium at a predetermined transmit frequency, and wherein: said synchronizer means supplies the sample clock signal at a frequency which substantially corresponds to the transmit frequency and in a predetermined fixed phase relationship with the primary signals.

Claim 25

Dependent Claim 51 words

A transceiver as defined in claim 22 wherein the one analog signal which establishes the sample clock signal comprises: a calibration signal which is periodically inserted in a serial stream of analog signals transmitted by the transmitter means; and each calibration signal is of a predetermined amplitude and a predetermined phase.

Claim 26

Dependent Claim 104 words

A transceiver as defined in claim 23 wherein each calibration signal is immediately preceded and immediately followed by an interval of silence wherein no analog signal is transmitted, and said receiver means further comprises: means responsive to the calibration signal for determining the amount of residual signal remaining on the medium during the immediately following interval of silence, the residual signal being an intersymbol interference (ISI) effect created by and related by a predetermined fraction to the preceding calibration signal; and means for eliminating the ISI effect during the conversion of each analog signal into the corresponding digital output value of the analog signal.

Claim 27

Dependent Claim 71 words

A transceiver as defined in claim 24 wherein: the ISI effect is a fractional value established by amplitude of the residual signal in the interval following the calibration signal relative to the amplitude of the calibration signal; and said ISI effect elimination means multiplies the ISI fractional value and a value representative of the preceding converted analog signal to establish the amount of ISI effect on a currently received analog signal.

Claim 28

Dependent Claim 36 words

A transceiver as defined in claim 25 wherein: said ISI elimination means further subtracts the amount of the ISI effect from a value representative of a current received analog signal to supply an ISI compensated value.

Claim 29

Dependent Claim 37 words

A transceiver as defined in claim 26 wherein said receiver means further comprises: means for adjusting the gain of the receiver means to compensate for the effects of signal attenuation or signal amplification by the communication medium.

Claim 30

Dependent Claim 46 words

A transceiver as defined in claim 27 wherein said gain adjusting means comprises: means for supplying a normalized value representative of the ISI compensated value relative to a value representative of the full amplitude of the calibration signal, the normalized value establishing the digital output value.

Claim 31

Dependent Claim 32 words

A transceiver as defined in claim 28 wherein: said means for supplying a normalized value operatively divides the ISI compensated value by a value representative of the amplitude of the calibration signal.

Claim 32

Dependent Claim 33 words

A transceiver as defined in claim 29 wherein said receiver means further comprises: thresholding means receptive of the normalized value and operative for classifying and fractional normalized value into the digital output value.

Claim 33

Dependent Claim 51 words

A transceiver as defined in claim 18 wherein said receiver means further comprises; means for determining the amount of residual signal effect created by an immediately preceding received analog signal; and means for eliminating the residual signal effect during the conversion of each received analog signal to the digital output value.

Claim 34

Dependent Claim 47 words

A transceiver as defined in claim 31 wherein said residual signal effect elimination means supplies a compensated signal, and further comprising: thresholding means receptive of the compensated signal and operative for classifying any fractional compensated signal into one value of two most closely related digital output values.

Claim 35

Dependent Claim 229 words

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 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.

Claim 36

Dependent Claim 229 words

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 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.

Claim 37

Dependent Claim 48 words

A transceiver as defined in claim 33 wherein said residual signal effect elimination means supplies a compensated signal, and further comprising: thresholding means receptive of the compensated signal and operative for classifying any fractional compensated signal into one value of the two most closely related digital output values.

Claim 38

Dependent Claim 49 words

A transceiver as defined in claim 33 wherein said receiver means further comprises: 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.

Claim 39

Dependent Claim 36 words

A transceiver as defined in claim 35 further comprising: thresholding means receptive of the normalized value and operative for classifying any fractional normalized value into one value of the two most closely related digital output values.

Claim 40

Dependent Claim 194 words

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 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.

Claim 41

Dependent Claim 194 words

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 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.

Claim 42

Dependent Claim 36 words

A transceiver as defined in claim 37 further comprising: thresholding means receptive of the normalized value and operative for classifying any fractional normalized value into one value of the two most closely related digital output values.

Claim 43

Dependent Claim 190 words

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: 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.

Claim 44

Dependent Claim 190 words

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: 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.

Claim 45

Dependent Claim 57 words

A transceiver as defined in claim 39 wherein: the transmitter means transmits each analog signal as a pulse analog signal having predetermined time-domain characteristics; and the time-domain filter means produces a maximum output energy in correspondence to a received pulse analog signal having the predetermined time-domain characteristics and substantially attenuates signals from the medium of other characteristics.

Claim 46

Dependent Claim 26 words

A transceiver as defined in claim 31 wherein the analog signals on the communication medium are each substantially in the form of a sine pulse waveform.

Claim 47

Dependent Claim 51 words

A transceiver as defined in claim 39 wherein said receiver means further comprises: means for determining the amount of residual signal effect created by an immediately preceding received analog signal; and means for eliminating the residual signal effect during the conversion of each received analog signal to the digital output value.

Claim 48

Dependent Claim 47 words

A transceiver as defined in claim 42 wherein said residual signal effect elimination means supplies a compensated signal, and further comprising: thresholding means receptive of the compensated signal and operative for classifying any fractional compensated signal into one value of two most closely related digital output values.

Claim 49

Dependent Claim 200 words

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: 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.

Claim 50

Dependent Claim 200 words

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: 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.

Claim 51

Dependent Claim 23 words

A transceiver as defined in claim 44 wherein said synchronizer means establishes the fixed phase relationship in response to a single calibration signal.

Claim 52

Dependent Claim 140 words

A transceiver as defined in claim 45 further comprising: transmitter means for transmitting the analog signals on the medium; and means for supplying a reference clock signal to the transmitter means and the receiver means to establish the transmit frequency; and wherein said synchronizer means further comprises: means receptive of the reference clock signal for supplying a plurality of phase shifted versions of the reference clock signal, each phase shifted version being phase shifted by an approximately equal amount from the preceding and following phase shifted versions over the period of the reference clock signal; and selection means responsive to the asynchronous signal and each of the phase shifted versions for establishing the sample clock signal from one of the phase shifted versions which undergoes a transition within a predetermined time relative to an event defined by the asynchronous signal.

Claim 53

Dependent Claim 43 words

A transceiver as defined in claim 46 wherein: said means for supplying a plurality of phase shifted versions of the reference clock signal comprises a multi-tap delay line, and each tap of the multi-tap delay means supplies at least one phase shifted version.

Claim 54

Dependent Claim 84 words

A transceiver as defined in claim 47 wherein said selection means comprises: register means receptive of all of the phase shifted versions and responsive to the asynchronous signal, for setting values therein which correspond to the states of the phase shifted versions upon the occurrence of the asynchronous signal; and phase selecting means receptive of the values set in the register and operative for determining from those set values the one phase shifted version from which the sample clock signal is to be derived.

Claim 55

Dependent Claim 110 words

A transceiver as defined in claim 48 wherein: said phase selecting means determines from the set values which one of the phase shifted versions or an inversion of a phase shifted version is to be supplied as the sample clock signal, and operatively supplies a selection control signal which identifies the one phase shifted version or the inversion thereof which is to be supplied; and further comprising: means receptive of the phase shifted versions and operative for supplying the phase shifted versions and for supplying inversions of the phase shifted versions as a selected signal from which the sample clock signal is derived in response to the selection control signal.

Claim 56

Dependent Claim 84 words

A transceiver as defined in claim 49 further comprising: means receptive of the selected signal and operative for supplying the sample clock signal at a predetermined frequency which is substantially less than the reference clock signal, said sample clock signal supplying means creating a transition in the sample clock signal immediately upon the occurrence of the asynchronous signal and thereafter supplying transitions of the sample clock signal in coincidence with the transitions of the selected one of the phase shifted versions or inversions thereof.

Claim 57

Dependent Claim 239 words

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: 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.

Claim 58

Dependent Claim 239 words

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: 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.

Claim 59

Dependent Claim 57 words

A transceiver as defined in claim 51 wherein: said adjusting means substantially eliminates the effect of gain or attenuation by mathematically dividing a value related to the initial digital value by the digital value of the maximum sampled amplitude of a received calibration signal to normalize the digital value before supplying it as the digital output value.

Claim 60

Dependent Claim 36 words

A transceiver as defined in claim 52 further comprising: thresholding means receptive of the normalized digital value for classifying any fractionalized digital value into one value of the two most closely related predetermined digital output values.

Claim 61

Dependent Claim 225 words

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: 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).

Claim 62

Dependent Claim 225 words

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: 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).

Claim 63

Dependent Claim 114 words

A transceiver as defined in claim 54 wherein each calibration signal is immediately followed by a silent interval wherein no analog signal is transmitted, and further comprising: means responsive to a residual signal on the medium during the silent interval which follows the calibration signal and operative for latching the value of the residual signal as an ISI value between sequential calibration signals; means responsive to the calibration signal and operative for latching the maximum amplitude of the calibration signal as a peak value between sequential calibration signals; and means receptive of the ISI value and the peak value for dividing the ISI value by the peak value to obtain an ISI compensation factor.

Claim 64

Dependent Claim 51 words

A transceiver as defined in claim 55 wherein: said adjusting means substantially eliminates the effect of intersymbol interference by mathematically multiplying the digital output value by the value of the ISI compensation factor and subtracting the result of the multiplication from the initial digital value derived from a received analog signal.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-09-16	1995-03-18	1995-09-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-09-16	1999-03-18	1999-09-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-09-16	2003-03-18	2003-09-17	$7700.00	Window Closed / Lapsed

Multibit amplitude and phase modulation transceiver for LAN

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