Time-sharing subscriber communications system

Claim 2

A time-sharing subscriber communications system wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a given frequency band over a single wideband circuit connected to the various subscriber terminals, which system comprises a wideband circuit for carrying signals within a wideband of frequencies including a given frequency band; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are Sources of analog input signals and interfaced to the wideband circuit at one end of the seriesconnected subscriber terminals, for transmitting in the given frequency band, a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal to provide a transmitted time-division multiplexed signal containing time slots and for placing in the time slots, in a predetermined order related to the series order of the subscriber terminals, information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping off from the time-division multiplexed signal received on the wideband circuit the information contained in the one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information; characterized by the feature that during each frame the transmitter terminal modulating means (a) provides, in the predetermined order, a predetermined number of pulses corresponding to the predetermined number of time slots, wherein the pulses are spaced at intervals corresponding to the values of said received analog input signals, and (b) instantaneously switches the voltage level of the time-division multiplexed signal transmitted on the wideband circuit across the nominal zero axis between a nominal positive value and a nominal negative value in response to each provided pulse, whereby each time slot is defined by the interval between successive said zero-axis crossings and the information contained in each time slot is defined by the duration of said each time slot.

Claim 3

A time sharing subscriber communications system according to claim 1, wherein the subscriber terminal further comprises a transmitting means for retransmitting a portion of the time-division multiplexed signal received on the wideband circuit and for newly transmitting in one or more of the various time slots of each frame new information related to said subscriber terminal, wherein each frame of the time-division multiplexed signal transmitted from the subscriber terminal transmitting means contains the predetermined number of time slots.

Claim 4

A time-sharing subscriber communications system according to claim 2, further comprising a subscriber terminal interface circuit comprising a first terminal operatively coupled to the subscriber terminal demodulating means for receiving the analog output signal; a first operational amplifier having a first input coupled to the first terminal and a second input coupled to ground, wherein a signal provided at the first operational amplifier first input is inverted at the first operational amplifier output; a second terminal operatively coupled to a subscriber output system for providing at the second terminal an analog signal containing new information related to said subscriber terminal and operatively coupled to the output of the first operational amplifier, wherein at the second terminal there appears the sum of said analog signal containing new information related to said subscriber terminal and a signal from the output of the first operational amplifier; and a second operational amplifier having a first input which is connected for additively receiving signals from the first and second terminals, a second input which is connected to ground, and an output which is operatively coupled to the subscriber terminal transmitting means, whereby the analog signal containing new information related to said subscriber terminal is provided from the output of the second operational amplifier to the subscriber terminal transmitting means, and whereby the analog output signal is provided from the second terminal to said subscriber output systEm.

Claim 5

A time-sharing subscriber communications system according to claim 2, further comprising a receiver terminal connected to a second given number of output channels which can carry analog output signals and interfaced to the wideband circuit for receiving in the given frequency band at the opposite end of the series-connected subscriber terminals, a time-division multiplexed signal having a series of frames and the predetermined number of time slots in each frame, which receiver terminal comprises a demodulating means for tapping off from the time-division multiplexed signal received on the wideband circuit the newly transmitted information contained in the time slots related to each of the subscriber terminals, and for providing analog output signals corresponding to the tapped-off information to various output channels respectively related to various ones of the subscriber terminals.

Claim 6

A time-sharing subscriber communications system according to claim 4, wherein the receiver terminal is located at a first location and interfaced with the wideband circuit in the given frequency band at the first location and the transmitter terminal is located at the first location and interfaced with the wideband circuit in the given frequency band at a remote location, and wherein the system further comprises a modulator at the first location for placing the transmitted time-division multiplexed signal on the wideband circuit at the first location in a second frequency band; and a demodulator at the remote location for removing the transmitted time-division multiplexed signal from the second frequency band and for placing the transmitted time-division multiplexed signal on the wideband circuit at the remote location in the given frequency band.

Claim 7

A time-sharing subscriber communications system according to claim 4, wherein the receiver terminal demodulating means comprise a ring counter/shift register operatively coupled to the wideband circuit for receiving the time-division multiplexed signal, which ring counter/shift register comprises counting means for stepping one count in response to each time slot received during each frame, with the durations between steps being the durations of the time slots; and output terminals connected to the counting means, at various different combinations of which output terminals, signals are provided, in response to the stepping, during the intervals while each different time slot is being received; a plurality of output channel gates corresponding to the number of output channels, each of which output channel gates is connected to different combinations of the ring counter/shift register output terminals, wherein tapped-off signals are provided from the various output channel gates during the interval in which the time slot corresponding to the output channel to which the output channel gate corresponds is being received; a plurality of integrating circuits, each of which is operatively coupled to one of the output channel gates for providing, in response to the tapped-off signal, an integrated signal of linearly varying amplitude during the duration of the corresponding time slot being received; and a plurality of sample, hold, and reset circuits, each of which is operatively coupled to one of the output channel gates and to the integrating circuit which is coupled to the same output channel gate, for providing an analog output signal for the corresponding output channel, by sampling the amplitude of the integrated signal during each corresponding time slot, by holding the sampled signal until the next corresponding time slot, and by resetting for resampling upon the recurrence of each corresponding time slot.

Claim 8

A time-sharing subscriber communications system according to claim 4, further comprising an interface circuit for interfacing a transmitter terminal first input channel and a receiver terminal first output channel to a pair of communication lines, which iNterface circuit comprises a first terminal operatively coupled to the receiver terminal first output channel for receiving the analog output signal; a first operational amplifier having a first input coupled to the first terminal and a second input coupled to ground, wherein a signal provided at the first operational amplifier first input is inverted at the first operational amplifier output; a second terminal operatively coupled to the pair of communication lines and to the output of the first operational amplifier, for providing at the second terminal the sum of an analog input signal from the pair of communication lines and the output signal from the operational amplifier; and a second operational amplifier having a first input which is connected for additively receiving signals from the first and second terminals, a second input which is coupled to ground, and an output which is operatively coupled to the transmitter terminal first input channel; whereby the analog input signal is provided from the output of the second operational amplifier to the transmitter terminal first input channel; and whereby the analog output signal is provided from the second terminal to said communication lines.

Claim 9

A time-sharing subscriber communications system according to claim 4, wherein telephone services are provided; wherein a transmitter terminal first input channel comprises an audio signal input line and a supervisory signal input line; wherein a receiver terminal first output channel comprises an audio signal output line and a supervisory signal output line; and wherein the time sharing subscriber communications system further comprises an interface circuit for interfacing the transmitter terminal first input channel and the receiver terminal first output channel to a pair of telephone lines, which interface circuit comprises a first terminal operatively coupled to the audio signal output line of the receiver terminal first output channel for receiving an audio output signal portion of the analog output signal; a first operational amplifier having a first input coupled to the first terminal and a second input coupled to ground, wherein a signal provided at the first operational amplifier first input is inverted at the first operational amplifier output; a second terminal operatively coupled to said pair of telephone line terminals and to the output of the first operational amplifier, for providing at the second terminal the sum of an audio input signal from said pair of telephone lines and the output signal from the first operational amplifier; a second operational amplifier having a first input which is connected for additively receiving signals from the first and second terminals, a second input which is coupled to ground, and an output which is operatively coupled to the audio signal input line of the transmitter terminal first input channel; a ringing detector circuit connected to said pair of telephone lines and operatively coupled to the supervisory signal input line of the transmitter terminal first input channel, which ringing detector circuit, in response to detecting a ringing signal from said pair of telephone lines, provides a supervisory signal indicating a ringing signal to said supervisory signal input line; a first switch in one line of said pair of telephone lines; a relay driver circuit and relay for operating the first switch, which relay driver is operatively coupled to the supervisory signal output line of the receiver terminal first output channel for operating the first switch to provide a dialing pulse on the telephone line in response to the receipt of a supervisory signal indicating a dialing pulse from the supervisory signal output line of the receiver terminal first output channel, and for closing the first switch in response to the receipt of a supervisory signal indicating an off-hook signal from the supervisory signal output line of the receiver terminal first output channel for enablinG the operative coupling of the second terminal to said pair of telephone lines; whereby said audio input signal is provided from the output of the second operational amplifier to the audio signal input line of the transmitter terminal first input channel; and whereby said audio output signal is provided from the second terminal to said pair of telephone lines.

Claim 10

A time-sharing communications system according to claim 3, wherein the transmitter terminal further comprises a clocking signal generator for providing a clocking signal having a predetermined frequency to produce sync pulses in the time-division multiplexed signal wherein the endings of the sync pulses occur at the predetermined frequency to define the beginning of each frame; and the subscriber terminal transmitting means comprises an inverter operatively coupled to the wideband circuit for inverting the received time-division multiplexed signal; a ring counter/shift register circuit operatively coupled to the wideband circuit for receiving the time-division multiplexed signal, which ring counter/shift register comprises counting means for stepping one count in response to each time slot received during each frame, with the durations between steps being the durations of the time slots, and output terminals connected to the counting means, at various different combinations of which output terminals signals are provided, in response to the stepping, during the intervals while each different time slot is being received; a first pulse circuit including a first output gate connected to a combination of the ring counter/shift register output terminals wherein a tapped-off signal is provided from the first output gate during the interval in which the first time slot of the received time-division multiplexed signal is being received, and wherein, in response to the leading edge of said tapped-off signal corresponding to the first time slot, a first pulse signal is provided from the first pulse circuit at the end of each sync pulse of the received time-division multiplexed signal; and a second pulse circuit including a second output gate connected to a combination of the ring counter/shift register output terminals wherein a tapped-off signal is provided from the second output gate during the interval in which the last time slot of the received time-division multiplexed signal is being received, and wherein, in response to the trailing edge of said tapped-off signal corresponding to the last time slot, a second pulse signal is provided from the second pulse output circuit at the end of the last received time slot of the received time-division multiplexed signal; a modulator channel including a flip-flop and operational amplifier pair, wherein the flip-flop has a set input operatively coupled to the second pulse circuit for receiving each second pulse signal, and the operational amplified has a first input connected to the Q output of the flip-flop and to ground through a capacitor, a second input operatively coupled to a subscriber output system for providing at the second input an analog signal containing new information related to said subscriber terminal, and an output connected to the reset input of the flip-flop, wherein when a second pulse signal is received at the flip-flop set input, a pulse signal is provided at the output of the operational amplifier at an interval after the receipt of the second pulse signal at the paired flip-flop set input, wherein the duration of the interval is dependent upon the level of the analog input signal then provided at the second input of the operational amplifier, whereby the output signal from the operational amplifier resets the paired flip-flop to terminate the output signal from the operational amplifier to define the output signal from the operational amplifier as a pulse; a transmitter flip-flop having a set input operatively coupled to the output of the operational amplifier and a reset input operatively coupled to the first pulse circuit for receiving each first pulse signal; and an OR gate having inputs operatively coupled to the output of the inverter and to the Q output of the transmitter flip-flop and an output operatively coupled to the wideband circuit; whereby, in response to the inverted time-division multiplexed signal and the first pulse signal, the sync pulse of the time-division multiplexed signal provided to the wideband circuit from the OR gate ends at a time corresponding to the end of the first time slot of the received time-division multiplexed signal, and whereby, in response to the inverted time-division multiplexed signal, the second pulse signal, and the analog input signal then provided to the second input of the operational amplifier, a time slot containing new information related to the subscriber terminal is included in the time-division multiplexed signal provided to the wideband circuit from the OR gate in an interval immediately following the end of the last time slot of the inverted time-division multiplexed signal.

Claim 11

A time sharing communications system according to claim 9, wherein the subscriber terminal demodulating means comprises the ring counter/shift register of the subscriber terminal transmitting means, wherein a tapped-off signal is provided from the first output gate during the interval in which the first time slot of the received time-division multiplexed signal is being received; an integrating circuit which is operatively coupled to the first output gate for providing, in in response to the tapped-off signal corresponding to the first time slot, a signal of linearly varying amplitude during the duration of said first time slot; and a sample hold, and reset circuit which is operatively coupled to the first output gate and to the integrating circuit for providing an analog output signal corresponding to the information contained in the first time slot, by sampling the amplitude of the integrated signal from the coupled integrating circuit during said first time slot, by holding the sampled signal until the next first time slot, and by resetting for resampling upon the recurrence of each first time slot.

Claim 12

A time sharing subscriber communications system according to claim 1, wherein the subscriber terminal demodulating means comprise a ring counter/shift register operatively coupled to the wideband circuit for receiving the time-division multiplexed signal, which ring counter/shift register comprises counting means for stepping one count in response to each time slot received during each frame, with the durations between steps being the durations of the time slots; and output terminals connected to the counting means, at various different combinations of which output terminals signals are provided, in response to the stepping, during the intervals while each different time slot is being received; a number of output gates corresponding to the number of time slots containing information related to said subscriber terminal, each of which output gates is connected to different combinations of the ring counter/shift register output terminals, wherein a tapped-off signal is provided from a said output gate during the interval in which the corresponding time slot is being received; one or more integrating circuits, each of which is operatively coupled to one of the output gates for providing, in response to the tapped-off signal, an integrated signal of linearly varying amplitude during the duration of the corresponding time slot being received; and one or more sample, hold, and reset circuits, each of which is operatively coupled to one of the output gates and to the integrating circuit which is coupled to the same output gate, for providing an analog output signal corresponding to the information contained in the received corresponding time slot, by sampling the amplitude of the integrated signal from the coupled integrating circuit during each corresponding time slot, by hOlding the sampled signal until the next corresponding time slot, and by resetting for resampling upon each recurrence of the corresponding time slot.

Claim 13

A time sharing subscriber communications system according to claim 11, wherein telephone services are provided and wherein the subscriber terminal demodulator means further comprises a band pass filter operatively coupled to the output of the sample, hold, and reset circuit for detecting and providing that portion of the analog output signal which is an audio output signal; and a DC comparator circuit operatively coupled to the output of the sample, hold, and reset circuit for detecting and providing that portion of the analog output signal which is a supervisory signal.

Claim 14

A time-sharing communications system according to claim 1, characterized by the feature that the transmitter terminal comprises a clocking signal generator for providing a clocking signal having a predetermined frequency to produce sync pulses in the time-division multiplexed signal, wherein the endings of the sync pulses occur at the predetermined frequency to define the beginning of each frame; an OR gate; a plurality of modulator channels operatively coupled to the clocking signal generator, each of which modulator channels is operatively coupled to a separate one of said input channels, and connected to an input of the OR gate, and each of which modulator channels includes a flip-flop and operational amplifier pair; wherein all of the modulator channels are coupled to each other in tandem for serial operation in the said predetermined order; and wherein in each modulator channel the operational amplifier has a first input which is connected to the Q output of the flip-flop and connected to ground through a capacitor, a second input which is coupled to a said input channel, and an output which is connected to the reset input of the flip-flop, and operatively coupled to the set input of the flip-flop of the next tandem coupled modulator channel of the plurality of modulator channels, and to an input of the OR gate; wherein the flip-flop of the first modulator channel of the plurality of tandem coupled modulator channels has a set input which is operatively coupled to the clocking signal generator to receive the clocking signal, in response to which clocking signal the first modulator channel flip-flop delivers a signal to the first input of the paired operational amplifier, in response to which signal from the flip-flop the operational amplified provides an output pulse signal at an interval after the receipt of the clocking signal at the paired flip-flop set input, wherein the duration of the interval is dependent upon the level of the analog input signal then provided at the second input of the operational amplifier; and whereby the output signal from the operational amplifier resets the paired flip-flop to terminate the output signal from the operational amplifier to define the output signal from the operational amplifier as a pulse, is delivered as an indicating signal to the second modulator channel flip-flop to initiate the provision of a pulse signal from the second modulator channel, and is delivered to an input of the OR gate.

Claim 15

A time-sharing subscriber communications system according to claim 13, wherein the predetermined number of time slots exceeds the number of said input channels by a given number and wherein the transmitter terminal modulating means further comprises channel reservation means connected to tandem with the tandem connected modulator channels and between the first and last modulator channels for providing the given number of pulses to an input of the OR gate, wherein each of said given number of pulses is provided at a predetermined minimum interval following the preceding pulse delivered to an input of the OR gate, and for delivering an indicating signal to the next modulator channel of the tandem coupled modulator channels for initiating the provision oF a pulse from the next modulator channel.

Claim 16

A time sharing subscriber communications system according to claim 14, wherein the channel reservation means comprise one or more channel reservation boards, of which a first channel reservation board provides a first number of pulses to an input of the OR gate, which first channel reservation board comprises a first flip-flop and operational amplifier pair, wherein the first flip-flop has a set input operatively coupled to the means which provide the next preceding pulse to an input of the OR gate, and the first operational amplifier has a first input connected to the Q output of the first flip-flop and connected to ground through a first capacitor having a selected value, a second input connected to a source of bias voltage, and an output connected to the reset input of the first flip-flop and operatively coupled to an input of the OR gate, wherein when the means for providing the next preceding pulse to an input of the OR gate so provide said next preceding pulse, the said providing means also deliver an indicating signal to the set input of the first flip-flop, in response to which delivered indicating signal a pulse signal is provided at the first operational amplifier at the predetermined minimum interval following the provision of said next previous pulse to an input of the OR gate, wherein the predetermined minimum interval is dependent upon the selected value of the first capacitor and the value of the bias voltage; a second flip-flop and operational amplifier pair, wherein the second flip-flop has a set input operatively coupled to the first operational amplifier output, and the second operational amplifier has a first input connected to the Q output of the second flip-flop and connected to ground through a second capacitor having the selected value, a second input connected to the source of bias voltage, and an output connected to the reset input of the second flip-flop and operatively coupled to an input of the OR gate and to the set input of the first flip-flop; a line gate operatively coupled between the second operational amplifier output and the set input of the first flip-flop; and counting means having an input operatively coupled to the outputs of the first and second operational amplifiers, a first output operatively coupled to the line gate, and a second output operatively coupled to either the set input of a modulator channel flip-flop or the set input of a first flip-flop of another like channel reservation board; wherein upon the receipt of the first pulse at the counting means input after the counting means are reset, a signal is delivered from the counting means first output to the line gate to enable output pulses to be delivered from the second operational amplifier to the set input of the first number of pulses at the counting means input after the counting means are reset, the counting means are again reset, a signal is delivered from the counting means first output to the line gate to inhibit the delivery of output pulses from the second operational amplifier output to the first flip-flop set input, and a signal is delivered from the counting means second output for indicating the delivery of the last of the first number of pulses from the first channel reservation board to an input of the OR gate.

Claim 17

A time-sharing subscriber communications system, wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a given frequency band over a single wideband circuit connected to the various subscriber terminals, which system comprises a wideband circuit for carrying signals within a wideband of frequencies including a given frequency band; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are sources of analog input signaLs and interfaced to the wideband circuit at one end of the series-connected subscriber terminals for transmitting a time-division multiplexed signal in the given frequency band, which transmitter terminal comprises a clocking signal generator for providing a clocking signal having a predetermined frequency; a transmitting means for transmitting, in the given frequency band on the wideband circuit, a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which time-division multiplexed signal contains information related to various ones of the subscriber terminals in various time slots of each frame and contains a sync pulse, the ending of which sync pulse defines the beginning of each frame, wherein the endings of the sync pulses occur in response to the clocking signal at the predetermined frequency; and a modulating means for providing the time slots in the transmitted signal and for placing in the time slots, in a predetermined order related to the series order of the subscriber terminals, information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping-off from the time-division multiplexed signal received on the wideband circuit the information contained in one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information; characterized by the feature that during each frame the transmitter terminal modulating means provides to the transmitter terminal transmitting means, in the predetermined order, a pulse train commencing in response to the clocking signal and containing a predetermined number of pulses, corresponding to the predetermined number of time slots wherein the pulses are spaced at intervals corresponding to the values of said received analog input signals; and wherein during each frame the transmitter terminal transmitting means transmits on the wideband circuit a signal having a voltage level which is instantaneously switched across a nominal zero axis between a nominal positive value and a nominal negative value in response to each pulse in the pulse train provided by the transmitter terminal modulating means, whereby each time slot is defined by the interval between successive said zero-axis crossings and the information contained in each time slot is defined by the duration of said each time slot.

Claim 18

A time-sharing subscriber communications system, wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a given frequency band over a single wideband circuit connected to the various subscriber terminals, which system comprises a wideband circuit for carrying signals within a wideband of frequencies including a given frequency band; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are sources of analog input signaLs and interfaced to the wideband circuit at one end of the series-connected subscriber terminals for transmitting a time-division multiplexed signal in the given frequency band, which transmitter terminal comprises a clocking signal generator for providing a clocking signal having a predetermined frequency; a transmitting means for transmitting, in the given frequency band on the wideband circuit, a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which time-division multiplexed signal contains information related to various ones of the subscriber terminals in various time slots of each frame and contains a sync pulse, the ending of which sync pulse defines the beginning of each frame, wherein the endings of the sync pulses occur in response to the clocking signal at the predetermined frequency; and a modulating means for providing the time slots in the transmitted signal and for placing in the time slots, in a predetermined order related to the series order of the subscriber terminals, information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping-off from the time-division multiplexed signal received on the wideband circuit the information contained in one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information; characterized by the feature that during each frame the transmitter terminal modulating means provides to the transmitter terminal transmitting means, in the predetermined order, a pulse train commencing in response to the clocking signal and containing a predetermined number of pulses, corresponding to the predetermined number of time slots wherein the pulses are spaced at intervals corresponding to the values of said received analog input signals; and wherein during each frame the transmitter terminal transmitting means transmits on the wideband circuit a signal having a voltage level which is instantaneously switched across a nominal zero axis between a nominal positive value and a nominal negative value in response to each pulse in the pulse train provided by the transmitter terminal modulating means, whereby each time slot is defined by the interval between successive said zero-axis crossings and the information contained in each time slot is defined by the duration of said each time slot.

Claim 19

A time-sharing subscriber communications system according to claim 16, wherein the subscriber terminal further comprises a transmitting means for retransmitting a portion of the time-division multiplexed signal received on the wideband circuit and for newly transmitting in one or more of the various time slots of each frame new information related to said subscriber terminal, wherein each frame of the time-division multiplexed signal transmitted from the subscriber terminal transmitting means contains the predetermined number of time slots.

Claim 20

A time-sharing subscriber communications system according to claim 17, wherein the subscriber terminal transmitting means comprise an inverter operatively coupled to the wideband circuit for inverting the received time-division multiplexed signal; a ring counter/shift register circuit operatively coupled to the wideband circuit for receiving the time-division multiplexed signal, which ring counter/shift register comprises counting means for stepping one count in response to each time slot received during each frame, with the durations between steps being the durations of the time slots; and output terminals connected to the counting means, at various different combinations of which output terminals signals are provided, in response to the stepping, during the intervals while each different time slot is being received; a first pulse circuit including a first output gate connected to a combination of the ring counter/shift register output terminals wherein a tapped-off signal is provided from the first output gate during the interval in which the first time slot of the received time-division multiplexed signal is being received, and wherein, in response to the leading edge of said tapped-off signal corresponding to the first time slot, a first pulse signal is provided from the first pulse circuit at the end of each sync pulse of the received time-division multiplexed signal; and a second pulse circuit including a second output gate connected to a combination of the ring counter/shift register output terminals wherein a tapped-off signal is provided from the second output gate during the interval in which the last slot of the received time-division multiplexed signal is being received, and wherein, in response to the trailing edge of said tapped-off signal corresponding to the last time slot, a second pulse signal is provided from the second pulse output circuit at the end of the last received time slot of the received time-division multiplexed signal; and a modulator channel including a flip-flop and operational amplifier pair, wherein the flip-flop has a set input operatively coupled to the second pulse circuit for receiving each second pulse signal, and the operational amplifier has a first input connected to the Q output of the flip-flop and to ground through a capacitor, a second input operatively coupled to a subscriber output system for providing at the second input an analog signal containing new information related to said subscriber terminal, and an output connected to the reset input of the flip-flop, wherein when a second pulse signal is received at the flip-flop set input, a pulse signal is provided at the output of the operational amplifier at an interval after the receipt of the second pulse signal at the paired flip-flop set input, wherein the duration of the interval is dependent upon the level of the analog input signal then provided at the second input of the operational amplifier, whereby the output signal from the operational amplifier resets the paired flip-flop to terminate the output signal from the operational amplifier to define the output signal from the operational amplifier as a pulse; a transmitter flip-flop having a set input operatively coupled to the output of the operational amplifier and a reset input operatively coupled to the first pulse circuit for receiving each first pulse signal; and an OR gate having inputs operatively coupled to the output of the inverter and to the Q output of the transmitter flip-flop and an output operatively coupled to the wideband circuit; whereby, in response to the inverted time-division multiplexed signal and the first pulse signal, the sync pulse of the time-division multiplexed signal provided to the wideband circuit from the OR gate ends at a time corresponding to the end of the first time slot of the received time-division multiplexed signal, and whereby, in response to the inverted time-division multiplexed signal, the second pulse signal, and the analog input signal then provided to the second input of the operational amplifier, a time slot containing new information related to the subscriber terminal is included in the time-division multiplexed signal provided to the wideband circuit from the OR gate in an interval immediately following the end of the last time slot of the inverted time-division multiplexed signal.

Claim 21

A time-sharing subscriber communications systems according to claim 18, wherein the subscriber terminal demodulating means comprise the ring counter/shift register of the subscriber terminal transmitting means, wherein a tapped-off signal is provided from the first output gate during the interval in which the first time slot of the received time-division multiplexed signal is being received; an integrating circuit which is operatively coupled to tHe first output gate for providing, in response to the tapped-off signal corresponding to the first time slot, a signal of linearly varying amplitude during the duration of said first time slot; and a sample, hold, and reset circuit which is operatively coupled to the first output gate and to the integrating circuit for providing an analog output signal corresponding to the information contained in the first time slot, by sampling the amplitude of the integrated signal from the coupled integrating circuit during said first time slot, by holding the sampled signal until the next first time slot, by holding the sampled signal until the next first time slot, and by resetting for resampling upon the recurrence of each first time slot.

Claim 22

A time-sharing subscriber communications system according to claim 19, further comprising a subscriber terminal interface circuit comprising a first terminal operatively coupled to the output of the sample, hold and reset circuit for receiving the analog output signal; a first operational amplifier having a first input coupled to the first terminal and a second input coupled to ground, wherein a signal provided at the first operational amplifier first input is inverted at the first operational amplified output; a second terminal operatively coupled to a subscriber output system for providing at the second terminal an analog signal containing new information related to said subscriber terminal, and operatively coupled to the output of the first operational amplifier, wherein at the second terminal there appears the sum of said analog signal containing new information related to said subscriber terminal and a signal from the output of the first operational amplifier; and a second operational amplifier having a first input which is connected for additively receiving signals from the first and second terminals, a second input which is coupled to ground, and an output which is operatively coupled to the modulator channel operational amplifier second input; whereby the analog signal containing new information related to said subscriber terminal is provided from the output of the second operational amplifier to the modulator channel operational amplifier second input; and whereby the analog output signal is provided from the second terminal to said subscriber output system.

Claim 23

A time-sharing subscriber communications system according to claim 20, wherein telephone services are provided and the subscriber output system comprises a telephone set; wherein the subscriber terminal demodulating means further comprises a band pass filter operatively coupled to the output of the sample, hold, and reset circuit for detecting and providing that portion of the analog output signal which is an audio output signal; and a DC comparator circuit operatively coupled to the output of the sample, hold and reset circuit for detecting and providing that portion of the analog output signal which is a supervisory signal; wherein within the subscriber terminal interface circuit the first terminal is operatively coupled to the output of the band pass filter, and the second terminal is operatively coupled by telephone lines to said telephone set; wherein the subscriber terminal interface circuit further comprises a first switch for enabling the ringing of said telephone set, which first switch is operatively coupled to the output of the DC comparator circuit for operatively coupling a source of power for ringing said telephone set to said telephone set, and operates to enable the ringing of said telephone set upon the receipt of a supervisory signal indicating a ringing function from the DC comparator circuit; and a second switch operatively coupled by said telephone lines to said telephone set and responsive to the provision of an off-hook signal from said telephone set for providing a supervisory signal indicating an off-hook condition, and for breaking the operative coupling between the DC coMparator circuit and the first switch to prevent enabling of further ringing of said telephone set, and in response to the receipt of a dialing signal from said telephone set, the second switch provides a a supervisory signal indicating a dialing signal; and wherein the subscriber terminal transmitting means comprises a first voltage translator circuit operatively coupled to the output of the second operational amplifier and to the second input of the modulator channel operational amplifier for providing to the second input of the modulator channel operational amplifier an audio signal portion of said analog signal containing new information related to said subscriber terminal; and a second voltage translator circuit operatively coupled to the second switch and to the second input of the modulator channel operational amplifier for providing to the second input of the modulator channel operational amplifier a supervisory signal portion of said analog signal containing new information related to said subscriber terminal.

Claim 24

A time-sharing subscriber communications system according to claim 16, wherein the transmitter terminal modulating means comprises an OR gate having its output operatively coupled to the transmitter terminal transmitting means; a plurality of modulator channels operatively coupled to the clocking signal generator, each of which modulator channels is operatively coupled to a separate said input channel, and connected to an input of the OR gate, and each of which modulator channels includes a flip-flop and operational amplifier pair; wherein all of the modulator channels are coupled to each other in tandem for serial operation in a predetermined order related to the series order of the subscriber terminals; and wherein in each modulator channel the operational amplifier has a first input which is connected to the Q output of the flip-flop and connected to ground through a capacitor, a second input which is coupled to said input channel respectively related to said subscriber terminal, and an output which is connected to the reset input of the flip-flop, and operatively coupled to the set input of the flip-flop of the next tandem coupled modulator channel of the plurality of modulator channels, and to an input of the OR gate; wherein the flip-flop of the first modulator channel of the plurality of tandem coupled modulator channels has a set input which is operatively coupled to the clocking signal generator to receive the clocking signal, in response to which clocking signal the first modulator channel flip-flop delivers a signal to the first input of the paired operational amplifier, in response to which signal from the flip-flop the operational amplifier provides an output pulse signal at an interval after the receipt of the clocking signal at the paired flip-flop set input, wherein the duration of the interval is dependent upon the level of the analog input signal then provided at the second input of the operational amplifier; whereby the output signal from the operational amplifier resets the paired flip-flop to terminate the output signal from the operational amplifier to define the output signal from the operational amplifier as a pulse, is delivered as an indicating signal to the second modulator channel flip-flop to initiate the provision of a pulse signal from the second modulator channel, and is delivered to an input of the OR gate; and whereby, in response to the pulses delivered to the inputs of the OR gate, a pulse train is provided from the OR gate output to the transmitter terminal transmitting means.

Claim 25

A time-sharing subscriber communications system according to claim 22, wherein the transmitter terminal transmitting means comprises a pulse train generating flip-flop having a reset input operatively coupled to the clocking signal generator, having a toggle input operatively coupled to the output of the OR gate, having its set input operatively coupled to the output of The operational amplifier of the last tandem coupled modulator channel of the plurality of modulator channels, and having Q and/or outputs operatively coupled to the wideband circuit, wherein the pulse train generating flip-flop is reset in response to the clocking signal at the predetermined frequency and provides the time-division multiplexed signal at the Q and/or Q outputs wherein each sync pulse ends upon the pulse train generating flip-flop being reset and wherein the time slots are produced in response to the train of pulses provided to the toggle input terminal from the OR gate, and wherein, when the operational amplifier of the last tandem coupled modulator channel provides an output signal to the OR gate, an indicating signal is delivered from the last tandem coupled modulator channel operational amplifier output to the set input of the pulse train generating flip-flop, to provide the beginning of the next sync pulse of the time-division multiplexed signal provided at the Q and/or Q outputs of the pulse train generating flip-flop.

Claim 26

A time-sharing subscriber communications system wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a low frequency band over a single wideband circuit connected to the various subscriber terminals, and wherein the wideband circuit is connected to a television signal source for carrying television services in one or more high frequency bands, which system comprises a wideband circuit; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are sources of analog input signals and interfaced to the wideband circuit, at one end of the series-connected subscriber terminals, for transmitting in the low frequency band a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal to provide a transmitted time-division multiplexed signal containing time slots and for placing in the time slots in a predetermined order related to the series order of the subscriber terminals information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping off from the time-division multiplexed signal received on the wideband circuit the information contained in one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information characterized by the feature that during each frame the transmitter terminal modulating means provides, in the predetermined order, a predetermined number of pulses corresponding to the predetermined number of time slots, wherein the pulses are spaced at intervals corresponding to the values of said received analog input signals, and instantaneously switches the voltage level of the time-division multiplexed signal transmitted on the wideband circuit across a nominal zero axis between a nominal positive value and a nominal negative value in response to each provided pulse, whereby each time slot is defined by the interval between successive said zero-axis crossings and the information contained in each time slot is defined by the duration of said each time slot.

Claim 27

A time-sharing subscriber communications system wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a low frequency band over a single wideband circuit connected to the various subscriber terminals, and wherein the wideband circuit is connected to a television signal source for carrying television services in one or more high frequency bands, which system comprises a wideband circuit; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are sources of analog input signals and interfaced to the wideband circuit, at one end of the series-connected subscriber terminals, for transmitting in the low frequency band a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal to provide a transmitted time-division multiplexed signal containing time slots and for placing in the time slots in a predetermined order related to the series order of the subscriber terminals information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping off from the time-division multiplexed signal received on the wideband circuit the information contained in one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information characterized by the feature that during each frame the transmitter terminal modulating means provides, in the predetermined order, a predetermined number of pulses corresponding to the predetermined number of time slots, wherein the pulses are spaced at intervals corresponding to the values of said received analog input signals, and instantaneously switches the voltage level of the time-division multiplexed signal transmitted on the wideband circuit across a nominal zero axis between a nominal positive value and a nominal negative value in response to each provided pulse, whereby each time slot is defined by the interval between successive said zero-axis crossings and the information contained in each time slot is defined by the duration of said each time slot.

Claim 28

A time-sharing subscriber communications system wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a given frequency band over a single wideband circuit connected to the various subscriber terminals, which system comprises a wideband circuit for carrying signals within a wideband oF frequencies including a given frequency band; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are sources of analog input signals and interfaced to the wideband circuit at one end of the series-connected subscriber terminals, for transmitting in the given frequency band, a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal to provide a transmitted time-division multiplexed signal containing time slots and for placing in the time slots, in a predetermined order related to the series order of the subscriber terminals, information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping off from the time-division multiplexed signal received on the wideband circuit the information contained in the one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information; characterized by the feature that during each frame the transmitter terminal modulating means provides, in the predetermined order, a signal defining the predetermined number of time slots, wherein said defining signal is provided in response to the values of said received analog input signals, and wherein during each frame the voltage level of the time-division multiplexed signal transmitted on the wideband circuit is instantaneously switched across the nominal zero axis between a nominal positive value and a nominal negative value in response to said defining signal provided by the transmitter terminal modulating means, wherein each time slot is defined by the interval between a zero-axis crossing and the preceding zero-axis crossing and the information contained in each time slot is defined by the duration of said each time slot.

Claim 29

A time-sharing subscriber communications system wherein a time-division multiplexed signal, containing information related to various subscriber terminals in various time slots of each frame, is carried in a given frequency band over a single wideband circuit connected to the various subscriber terminals, which system comprises a wideband circuit for carrying signals within a wideband oF frequencies including a given frequency band; a plurality of subscriber terminals connected in series in the wideband circuit; and a transmitter terminal connected to a first given number of input channels which are sources of analog input signals and interfaced to the wideband circuit at one end of the series-connected subscriber terminals, for transmitting in the given frequency band, a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal to provide a transmitted time-division multiplexed signal containing time slots and for placing in the time slots, in a predetermined order related to the series order of the subscriber terminals, information corresponding to analog input signals received from various input channels respectively related to various ones of the subscriber terminals; and each of which subscriber terminals comprises a demodulating means for tapping off from the time-division multiplexed signal received on the wideband circuit the information contained in the one or more time slots related to that subscriber terminal, and for providing one or more analog output signals respectively corresponding to the tapped-off information; characterized by the feature that during each frame the transmitter terminal modulating means provides, in the predetermined order, a signal defining the predetermined number of time slots, wherein said defining signal is provided in response to the values of said received analog input signals, and wherein during each frame the voltage level of the time-division multiplexed signal transmitted on the wideband circuit is instantaneously switched across the nominal zero axis between a nominal positive value and a nominal negative value in response to said defining signal provided by the transmitter terminal modulating means, wherein each time slot is defined by the interval between a zero-axis crossing and the preceding zero-axis crossing and the information contained in each time slot is defined by the duration of said each time slot.

Claim 30

A transmitter terminal for transmitting a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal by placing in the time slots in a predetermined order information corresponding to analog input signals from a given number of input channels by providing in the predetermined order a number of pulses corresponding to the predetermined number of time slots and spaced at intervals related to the values of said received analog input signals, characterized by the feature that during each frame the modulating means instantaneously switches the voltage level of the time-division multiplexed signal across a nominal zero axis between a nominal positive value and a nominal negative value in response to each said provided pulse; whereby each time slot is defined by the interval between successive said zero-axis crossings.

Claim 31

A transmitter terminal for transmitting a time-division multiplexed signal having a series of frames and a predetermined number of time slots in each frame, which transmitter terminal comprises a modulating means for modulating the transmitted signal by placing in the time slots in a predetermined order information corresponding to analog input signals from a given number of input channels by providing in the predetermined order a number of pulses corresponding to the predetermined number of time slots and spaced at intervals related to the values of said received analog input signals, characterized by the feature that during each frame the modulating means instantaneously switches the voltage level of the time-division multiplexed signal across a nominal zero axis between a nominal positive value and a nominal negative value in response to each said provided pulse; whereby each time slot is defined by the interval between successive said zero-axis crossings.

Claim 32

A transmitter terminal according to claim 26, characterized by a clocking signal generator for providing a clocking signal having a predetermined frequency to produce sync pulses in the time-division multiplexed signal, wherein the endings of the sync pulses occur at the predetermined frequency to define the beginning of each frame; and OR gate; a plurality of modulator channels operatively coupled to the clocking signal generator, each of which modulator channels is operatively coupled to a separate one of said input channels, and connected to an input of the OR gate, and each of which modulator channels includes a flip-flop and operational amplifier pair; wherein all of the modulator channels are coupled to each other in tandem for serial operation in the said predetermined order; and wherein in each modulator channel the operational amplifier has a first input which is connected to the Q output of the flip-flop and connected to ground through a capacitor, a second input which is coupled to a said input channel, and an output which is connected to the reset input of the flip-flop, and operatively coupled to the set input of the flip-flop of the next tandem coupled modulator channel of the plurality of modulator channels, and to an input of the OR gate; wherein the flip-flop of the first modulator channel of the plurality of tandem coupled modulator channels has a set input which is operatively coupled to the clocking signal generator to receive the clocking signal, in response to which clocking signal the first modulator channel flip-flop delivers a signal to the first input of the paired operational amplifier, in response to which signal from the flip-flop the operational amplifier provides an output pulse signal at an interval after the receipt of the clocking signal at the paired flip-flop set input, wherein the duration of the interval is dependent upon the level of the analog input signal then provided at the second input of the operational amplifier; and whereby the output signal from the operational amplifier resets the paired flip-flop to terminate the output signal from the operational amplifier to define the output signal from the operational amplifier as a pulse, is delivered as an indicating signal to the second modulator channel flip-flop to initiate the provision of a pulse signal from the second modulator channel, and is delivered to an input of the OR gate.