Pulse width modulated self-clocking and self-synchronizing data transmission and method for a telephonic communication network switching system

Claim 2

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, and means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal, and means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit.

Claim 3

The switching interface system of claim 1 in which the network termination unit has an encoder for encoding data from the sources connected therewith into a pulse format and means responsive to the clock signal for transmitting the encoding data to the control unit in frequency synchronism with said transmission bit rate.

Claim 4

The switching interface system of claim 1 in which the extracted clock signal has a frequency which is substantially equal to the transmission bit rate frequency.

Claim 5

The switching interface system of claim 3 in which said control unit has a primary clock with a frequency which is a binary power multiple of the transmission bit rate, and said network termination unit has means for developing a clock signal which has a bit rate equal to the frequency of said primary clock.

Claim 6

The switching interface system of claim 1 in which said control unit has a decoder for decoding data from said network termination unit, and means for maintaining said decoder in frequency synchronism with the transmission bit rate of the transmitted pulse width binary encoded pulses.

Claim 7

The switching interface system of claim 5 in which said control unit includes means for maintaining said decoder in phase synchronism with the transmitted pulse width binary encoded pulses.

Claim 8

The switching interface system of claim 6 in which said phase synchronization means includes means to cause the time that a bit of data enters the encoding means to coincide with the instant that a bit emerges from the decoding means.

Claim 9

The switching interface system of claim 1 in which the control unit includes means for encoding said information in a binary pulse width modulated format with logic one states and logic zero states being represented by pulses of two different selected widths, respectively.

Claim 10

The switching interface system of claim 8 in which said pulses of two different selected widths have leading edge transitions occur at the same time during a bit interval.

Claim 11

The switching interface system of claim 9 in which said leading edge transitions are positive transitions.

Claim 12

The switching interface system of claim 8 in which said pulses of two different widths create pulse transitions in every data bit interval.

Claim 13

The switching interface system of claim 11 in which said pulse transitions are positive transitions.

Claim 14

The switching interface system of claim 1 in which said control unit includes means for periodically inserting phase synchronization pulses into said serially transmitted pulse width binary encoded pulses to provide phase synchronizational information to the network termination unit.

Claim 15

The switching interface system of claim 13 in which said control unit includes means responsive to an external clock for generating a phase reference signal, and means responsive to the phase reference signal generating means to insert said phase synchronization pulses into a stream of said serially transmitted pulse width binary encoded pulses.

Claim 16

The switching interface system of claim 13 in which said pulse width binary encoded pulses have a leading edge transition of a selected transitional sense, and said synchronizational pulses have a leading edge transition having the same transitional sense as said selected transitional sense of the binary encoded pulses.

Claim 17

The switching interface system of claim 15 in which said transitional sense is positive from a relatively low voltage to a relatively high voltage.

Claim 18

The switching interface system of claim 13 in which said network termination unit includes means responsive to said phase synchronization pulses to transmit data to said control unit in phase synchronism with said pulse width binary encoding data pulses at said preselected transmission bit rate.

Claim 19

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, and means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal including means for generating said clock signal at a frequency which is a preselected multiple of the transmission bit rate, and means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit.

Claim 20

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, and means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal including means for generating said clock signal at a frequency which is a preselected multiple of the transmission bit rate, and means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit.

Claim 21

The switching interface system of claim 18 in which said multiple is four.

Claim 22

The switching interface system of claim 13 in which each of the pulse width modulated pulses has a leading edge, and said clock signal extracting means includes a phase locked loop circuit with an input and an output, means for delaying the leading edge of the width modulated pulses to produce delayed pulse width modulated pulses, and means responsive to said delayed width modulated pulses for applying a corresponding delayed intermediate signal to the input of said phase locked loop, the output of said phase locked loop providing said clock signal at the preselected multiple of the transmission bit rate.

Claim 23

The switching interface system of claim 20 in which said delayed intermediate signal applying means includes a binary counter for producing an intermediate signal which has a frequency that is a preselected fraction of the transmission bit rate for interfacing with the input of the phase locked loop.

Claim 24

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate, and means for periodically inserting phase synchronization pulses into said serially transmitted pulse width binary encoded pulses to provide phase synchronizational information; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal, and means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit, means responsive to said phase synchronization pulses to transmit data to said control unit in phase synchronism with said pulse width binary encoding data pulses at said preselected transmission bit rate including a phase synchronization acquisition circuit for generating a synchronization control signal, and means responsive to the synchronization control signal for controlling the synchronous transmission of data to said control unit to maintain the transmission of data to the control unit in synchronization with the synchronization pulses generated thereby.

Claim 25

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate, and means for periodically inserting phase synchronization pulses into said serially transmitted pulse width binary encoded pulses to provide phase synchronizational information; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal, and means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit, means responsive to said phase synchronization pulses to transmit data to said control unit in phase synchronism with said pulse width binary encoding data pulses at said preselected transmission bit rate including a phase synchronization acquisition circuit for generating a synchronization control signal, and means responsive to the synchronization control signal for controlling the synchronous transmission of data to said control unit to maintain the transmission of data to the control unit in synchronization with the synchronization pulses generated thereby.

Claim 26

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate, and means for periodically inserting phase synchronization pulses into said serially transmitted pulse width binary encoded pulses to provide phase synchronizational information thereto; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal, means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit, means responsive to said phase synchronization pulses to transmit data to said control unit in phase synchronism with said pulse width binary encoding data pulses at said preselected transmission bit rate, including a counter triggered by said clock signal, means responsive to said counter for identifying the time division multiplexing channels of the telecommunication network, and means responsive to said synchronization control signal for maintaining said counter in phase synchronization with said phase synchronization pulses of said control unit.

Claim 27

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from some of said sources in a serial, pulse width binary format, means for serially transmitting pulse width binary encoded pulses of said encoding information at a preselected transmission bit rate, and means for periodically inserting phase synchronization pulses into said serially transmitted pulse width binary encoded pulses to provide phase synchronizational information thereto; and a network termination unit connected with other ones of said sources including means responsive to the serially transmitted, pulse width binary encoded pulses to extract therefrom a clock signal, means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the serially transmitted, pulse width binary encoded pulses for provision to said other ones of said sources connected with the network termination unit, means responsive to said phase synchronization pulses to transmit data to said control unit in phase synchronism with said pulse width binary encoding data pulses at said preselected transmission bit rate, including a counter triggered by said clock signal, means responsive to said counter for identifying the time division multiplexing channels of the telecommunication network, and means responsive to said synchronization control signal for maintaining said counter in phase synchronization with said phase synchronization pulses of said control unit.

Claim 28

The switching interface system of claim 23 in which said control unit has one microprocessor, said network termination unit has another microprocessor, and one of said time division multiplexing channels is dedicated to passing messages from said one microprocessor of the control unit to said other microprocessor of the network termination unit.

Claim 29

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from said sources as a series of data pulses in a serial pulse width binary format, means for generating pulse width encoded synchronization pulses, and means for transmitting said series of data pulses and pulse width encoded synchronization pulses together on a time division multiplexing basis at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said pulse width encoded synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the series of pulse width encoded data pulses for connection to said other ones of the sources connected with the network termination unit, and means responsive to said pulse width encoded synchronization pulses to control synchronization of the synchronous decoding means of the network termination unit with the encoding means of the control unit.

Claim 30

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from said sources as a series of data pulses in a serial pulse width binary format, means for generating pulse width encoded synchronization pulses, and means for transmitting said series of data pulses and pulse width encoded synchronization pulses together on a time division multiplexing basis at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said pulse width encoded synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted pulse width binary encoded pulses for synchronous decoding of the series of pulse width encoded data pulses for connection to said other ones of the sources connected with the network termination unit, and means responsive to said pulse width encoded synchronization pulses to control synchronization of the synchronous decoding means of the network termination unit with the encoding means of the control unit.

Claim 31

The switching interface system of claim 25 in which said data pulses have preselected pulse widths which differ from one another, and the synchronization pulses have a pulse width differing from the preselected pulse widths of the data pulses.

Claim 32

The switching interface system of claim 25 in which said network termination unit includes means for coding information from the other ones of said sources as a series of uniform binary data pulses, means for generating uniform synchronization pulses having a pulse width which is substantially the same as that of the uniform binary data pulses in synchronism with said pulse width encoded pulses, and means for transmitting said uniform synchronization pulses together with said uniform binary data pulses as a series of uniform pulses.

Claim 33

The switching interface system of claim 27 in which said control unit includes means responsive to said uniform synchronization pulses to decode said binary data pulses from the termination unit.

Claim 34

The switching interface system of claim 28 in which said control unit includes means responsive to said uniform synchronization pulses to determine whether they are in phase synchronization with transmission of the pulse width encoding synchronization pulses of the control unit.

Claim 35

The switching interface system of claim 27 in which at least some preselected ones of said uniform synchronization pulses received by the control unit have a binary logic state opposite to that of the pulse width encoding synchronization pulses transmitted by the control unit.

Claim 36

The switching interface system of claim 25 in which said series of data pulses are pulse width binarily encoded by said encoding means, with logic-one data pulses having a different pulse width than logic-zero data pulses, and in which said means for generating synchronization pulses generates said synchronization pulses with a pulse width that differs from both the logic-zero data pulses and the logic-one data pulses.

Claim 37

The switching interface system of claim 25 in which said preselected bit rate at which the data pulses in the synchronization pulses are transmitted is a substantially uniform rate, and said clock signals in the network termination unit are produced at a preselected uniform frequency which is a preselected multiple of the uniform bit rate.

Claim 38

The switching interface system of claim 25 in which said network termination unit has means for transmitting data from the other ones of the sources connected thereto to the control unit which includes means responsive to said synchronization pulses for maintaining said data transmitted to the control unit in phase synchronization with the pulse width encoded synchronization pulses from the control unit.

Claim 39

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from said sources as a series of data pulses, means for generating pulse width encoded synchronization pulses, and means for transmitting said series of data pulses and pulse width encoded synchronization pulses together on a time division multiplexing basis at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said pulse width encoded synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted information encoded for synchronous decoding of the series of data pulses for connection to said other ones of the sources connected with the network termination unit, means for transmitting data from the other ones of the sources connected thereto to the control unit which includes means responsive to said synchronization pulses for maintaining said data transmitted to the control unit in phase synchronization with the pulse width encoded synchronization pulses from the control unit including a phase synchronization acquisition circuit responsive to the synchronization pulses received at the network termination unit to develop a synchronization control signal for controlling the phase synchronization of the encoding means, and means responsive to said pulse width encoded synchronization pulses to control synchronization of the synchronous decoding means of the network termination unit with the encoding means of the control unit.

Claim 40

In a telecommunications network of transceiving informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from said sources as a series of data pulses, means for generating pulse width encoded synchronization pulses, and means for transmitting said series of data pulses and pulse width encoded synchronization pulses together on a time division multiplexing basis at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said pulse width encoded synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted information encoded for synchronous decoding of the series of data pulses for connection to said other ones of the sources connected with the network termination unit, means for transmitting data from the other ones of the sources connected thereto to the control unit which includes means responsive to said synchronization pulses for maintaining said data transmitted to the control unit in phase synchronization with the pulse width encoded synchronization pulses from the control unit including a phase synchronization acquisition circuit responsive to the synchronization pulses received at the network termination unit to develop a synchronization control signal for controlling the phase synchronization of the encoding means, and means responsive to said pulse width encoded synchronization pulses to control synchronization of the synchronous decoding means of the network termination unit with the encoding means of the control unit.

Claim 41

The switching interface system of claim 34 in which the phase synchronization acquisition circuit includes means associated with said encoding means for generating synchronization pulse receipt signals in response to receipt of said synchronization pulses from the control unit, a counter of said encoding means responsive to said synchronization control signal to count clock pulses in phase synchronism with the synchronization pulses, means responsive to said counter for generating said synchronization control signal to indicate when the next synchronization pulse should be received when the counter is in phase synchronism with the synchronization pulses, and means responsive to said synchronization pulse receipt signal and said synchronization control signal not being generated within a preselected time period of one another for generating an out-of-sync signal.

Claim 42

The switching interface system of claim 35 including means responsive to said out-of-sync signal for resynchronization of said counter.

Claim 43

The switching interface system of claim 34 in which said network termination unit includes means responsive to said out-of-sync signal for producing an out-of-sync indication.

Claim 44

In a telecommunications network of informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for binarily encoding information from a series of data pulses, means for decoding information received in a series of data pulses, means for generating a series of synchronization pulses of a preselected width differing from those of the data pulses, and means for transmitting said encoded information and said synchronization pulses together at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted binary encoded pulses for synchronous encoding and transmission of information from said other one of the sources to the control unit, and means responsive to said synchronization pulses to control phase synchronization of the encoding and transmitting means of said network termination unit with said decoding means of the control unit.

Claim 45

In a telecommunications network of informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for binarily encoding information from a series of data pulses, means for decoding information received in a series of data pulses, means for generating a series of synchronization pulses of a preselected width differing from those of the data pulses, and means for transmitting said encoded information and said synchronization pulses together at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted binary encoded pulses for synchronous encoding and transmission of information from said other one of the sources to the control unit, and means responsive to said synchronization pulses to control phase synchronization of the encoding and transmitting means of said network termination unit with said decoding means of the control unit.

Claim 46

The switching interface system of claim 38 in which said clock signal deriving means includes means responsive in part to the preselected bit rate of the series of data pulses to derive said clock signal.

Claim 47

In a telecommunications network or informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from a series of data pulses, means for decoding information received in a series of data pulses, means for generating synchronization pulses of a preselected width differing from those of the data pulses, and means for transmitting said encoded information and said synchronization pulses together at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted information encoded data pulses for synchronous encoding and transmission of information from said other one of the sources to the control unit, means responsive to said synchronization pulses to control phase synchronization of the encoding and transmitting means of said network termination unit with said decoding means of the control unit, means responsive to the synchronization pulses from the control unit for detecting phase nonsynchronization with said control unit, and means responsive to said nonsynchronization detecting means to alter the timing of the encoding and transmitting means to eliminate the condition of nonsynchronization.

Claim 48

In a telecommunications network or informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from a series of data pulses, means for decoding information received in a series of data pulses, means for generating synchronization pulses of a preselected width differing from those of the data pulses, and means for transmitting said encoded information and said synchronization pulses together at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted information encoded data pulses for synchronous encoding and transmission of information from said other one of the sources to the control unit, means responsive to said synchronization pulses to control phase synchronization of the encoding and transmitting means of said network termination unit with said decoding means of the control unit, means responsive to the synchronization pulses from the control unit for detecting phase nonsynchronization with said control unit, and means responsive to said nonsynchronization detecting means to alter the timing of the encoding and transmitting means to eliminate the condition of nonsynchronization.

Claim 49

In a telecommunications network of informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from a series of data pulses, means for decoding information received in a series of data pulses, means for generating synchronization pulses of a preselected width differing from those of the data pulses, and means for transmitting said encoded information and said synchronization pulses together at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted information encoded data pulses for synchronous encoding and transmission of information from said other one of the sources to the control unit, means responsive to said synchronization pulses to control phase synchronization of the encoding and transmitting means of said network termination unit with said decoding means of the control unit, and means responsive to the synchronization pulse from the control unit for transmitting to the control unit an indication of phase nonsynchronization.

Claim 50

In a telecommunications network of informational sources, the improvement being a switching interface system for communication between said sources, comprising: a control unit connected with some of said sources including means for encoding information from a series of data pulses, means for decoding information received in a series of data pulses, means for generating synchronization pulses of a preselected width differing from those of the data pulses, and means for transmitting said encoded information and said synchronization pulses together at a preselected bit rate; and a network termination unit connected with other ones of said sources including means responsive to at least said synchronization pulses to derive a clock signal, means responsive to said clock signal and said serially transmitted information encoded data pulses for synchronous encoding and transmission of information from said other one of the sources to the control unit, means responsive to said synchronization pulses to control phase synchronization of the encoding and transmitting means of said network termination unit with said decoding means of the control unit, and means responsive to the synchronization pulse from the control unit for transmitting to the control unit an indication of phase nonsynchronization.

Claim 53

The method of claim 42 including the step of employing the extracted clock signal to transmit a stream of data from the termination unit to the controller circuit in synchronism with the transmissions of the pulse width modulated data stream transmitted to the termination unit.

Claim 54

The method of claim 42 including the steps of inserting a pulse width modulated synchronization pulse into the self-clocking pulse width modulated binary data stream, and employing the pulse width modulated synchronization pulse to maintain phase synchronization of communications between the controller circuit and the termination circuit.

Claim 55

The method of claim 42 in which the step of transmitting includes the step of transmitting each pulse width modulated pulse at the beginning of each clock cycle.