Abstract: Communications engineers have a long acquaintance with the “multiple-access” problem, i.e., the problem of providing the means whereby many senders of information can share a common communications resource. The “classical” solution has been to do some form of multiplexing (e.g., time-division multiplexing (TDM) or frequency-division multiplexing (FDM) in order to parcel out the resource equitably among the senders.) A fixed division of the resources, however, becomes inefficient when the requirements of the users vary with time. The classical “fix” for the multiplexing solution is to add some form of demand-assignment so that the particular division of resources can be adapted to meet the changing requirements. Such demand-assigned multiplexing techniques have proved their worth in a myriad of multiple-access applications.

Abstract: It has been proposed to base advanced Digital Switching networks on a modular array using Digital Switch Modules (DSM). It has been found, for large traffic handling Digital switching systems, that the cross-office delay encountered in multi-stage networks based on 8×8 Digital Switching Modules (DSM's) is unacceptably large. To maintain the flexibility provided by the multi-stage concepts a demultiplexing/mixing/remultiplexing stage (DMR) is introduced to replace intermediate DSM ranks. The DMR is used to provide a preset time/space switching function within the total trunking providing the availability of a controlled stage but without the control and delay penalties associated with a fully flexible DSM or the control and link blocking disadvantages associated with a pure space switch. The DMR effectively acts as a pre-programmed or counter driven DSM. By adjusting the degree of DMR function it is possible to provide a very wide range of switch sizes which uses a common organization in the controlled switch stages. The operation of the DMR may be defined in conjuction with a mirror imaging correlation function to provide a constant switch loop delay for duplex connections.

Abstract: A service integrated transmission system for transmitting, over a light transmission path, digital signals having a transmission band whose upper limit frequency corresponds to the maximum bit rate of the signals to be transmitted, the transmission being effected by simultaneously transmitting, over the transmission path, digital signals having a high bit rate only in an upper part of the transmission band and digital signals having a low bit rate only in a lower part of the transmission band. The system includes a transmitter at one end of the path which separately multiplexes low bit rate signals into a narrowband signal and high bit rate signals into a broadband signal, combines those multiplexed signals, and modulates a light source with the combined signal. A receiver at the other end of the path converts the modulated light signal into a demodulated electrical signal, separates the two multiplexed signals, and then demultiplexes each of the latter signals.

Abstract: The invention relates to a method and apparatus for simultaneously transmitting a plurality of television signals on a single radio link, in which the television signals are converted according to a digital (PCM) code, the digital signals are collected in suitable memories, said signals are read out at a rate multiple of the introduction rate, said signals are combined in a single sequence multiplexing, are again converted to analog signals, are transmitted through a radio link and at their arrival are again converted to a digital form, the luminance and chrominance signals are separated by means of a demultiplexer, are introduced at a predetermined rate in suitable memories, are read out from the memories at a rate which is a submultiple of the introduction rate, are converted into analog signals corresponding to the luminance and chrominance of each signal and are sent to as many PAL coders as are the television signals to be reconstituted.

Abstract: A high speed analog-to-digital conversion method and apparatus including a plurality of parallel analog-to-digital converters is disclosed A clock signal is applied to each of the analog-to-digital converters at different phase relation to increase the equivalent sampling frequency by multiplexing the outputs into a serial form A reference signal such as a linear ramp or sawtooth signal is used to maintain the correct phase relation, thereby eliminating any errors due to differences in electrical characteristics among the analog-to-digital converters Such correction may be performed automatically by using a CPU before digitizing an analog input signal or at any desired time

Abstract: Apparatus for gathering data about a plurality of chemical or physical conditions, e.g. on industrial plants, utilizes a plurality of passive optical sensors. Light for the sensors is provided by a common broadband source, and distributed by an optical fiber from which light of a selected color is withdrawn for each sensor in turn, the color selected for each sensor being different from that selected for the other sensors. Each color is modified by its respective sensor as a function of changes in the conditions applied to the sensor, and all the modified colors are conveyed along a common data bus to be demultiplexed and the data displayed. The colors may be supplied by the data bus to detection means simultaneously or sequentially. Passive optical sensors avoid electrical interference and incendiary risks due to electrical sparking, and color multiplexing avoids difficulties associated with other forms of multiplexing in plant environments.

Abstract: An article theft detection system for identifying which of two adjacent passageways a protected article (18) passes. Each passageway is provided with spaced apart interrogation and transmitter antennas (10, 12), but a single receiver antenna (14) services both passageways. Multiplexing is used to energize the interrogation antennas (10, 12) in alternate sequence. The single receiver antenna (14) is connected to a single receiver (34) whose output is connected through switches (38, 40), synchronized with the interrogation multiplexing, to separate alarms for each passageway.

Abstract: A common controller in the form of a programmed digital sequencer executes a series of instructions to control multiplexing-demultiplexing overhead channel format generation, frame synchronization stuff-destuff operation and automatic channel assignment in a digital TDM multiplexer-demultiplexer combination at one communication terminal to enable multiplexing N input data signals each having a predetermined bit rate into a transmitted synchronous data stream having a predetermined fixed data format and a given bit rate greater than the sum of the predetermined bit rates and to demultiplex N output data signals each having the predetermined bit rate from a received synchronous data stream having the data format and the given bit rate, where N is an integer greater than one. The disclosed common controller can be used with synchronous input and output data signals or for asynchronous input and output data signals wherein the asynchronous input and output data signals are distributed throughout the fixed data format in the time slots thereof evenly due to the automatic channel assignment. The programmed digital sequencer includes program memory means and support logic means coupled to the memory means to supply control signals in response to a plurality of digital codes present in the program memory means for multiplexing, demultiplexing, overhead channel format generation frame synchronization, stuff-destuff control and automatic channel assignment.

Abstract: A new transmission system configuration is disclosed which takes advantage of the special properties of lightwave devices and the extensive availability of frequency space on optical fibers. The system employs a combination of time and frequency multiplexing at the transmitter, and frequency demultiplexing at the receiver. An advantageous result of combining time and frequency multiplexing is to relax the tolerance requirements on filters at the transmitter. A further advantage is to minimize the effects of mode dispersion introduced by the fiber.

Abstract: This paper reports on an experimental system of an integrated communication network built with components representing the state-of-the-art in the area of optical fiber transmission and large-scale integration of logic functions. These components make it possible to apply new concepts for signal processing, transmission, and switching in the experimental system. The large bandwidth of optical channels allows the transmission of all kinds of communication services including data, audio, and video, while semiconductor technology offers low cost realization and mass production of complex signal processing and switching functions to handle all these services within one network. The concept of the system is presented and results on system components and subsystems are given.

Abstract: A plurality of CML integrated circuit chips with input and output gates connected in a circular access linkage loop output-to-input with each chip having an interface mechanism comprising an interface register and a bypass arrangement between the input gate and the output gate so that information may flow from a transmitter output gate to a receiver input gate uni-directionally, (clockwise or counter-clockwise) through the loop by means of the bypass with minimal delay. Utilizing this circular access linkage loop together with a junction box, a number of access loops can be joined together to increase the number of chips which can be linked together. Also disclosed is a multiplexing scheme utilizing the circular access linkage loop for increasing the gate per pin ratio and for higher speed communication between chips.

Abstract: The design of a (demultiplexer using distributed coupling between two step index single mode fibers of different dispersion characteristics is presented. The required fiber properties can easily be provided by modem single mode fiber technology. It is shown that this simple, low loss coupling technique allows the multiplexing of a tens of channels in the 1.25 um-1.6 um wavelength range with a 20 dB inter-channel isolation. The influence of the parameters of the structure on its filtering properties is discussed. introduced in a distributed coupling between two bent parallel fibers [6], but not enough for multiplexing a few channels in a restricted frequency band.

Abstract: A data communication arrangement for multiplexing an asynchronous binary data signal (113) with a synchronous binary data signal (112) by the timely insertion of an extra data bit (107) in selected synchronous data words and by delaying the transmission of the resulting multiplexed data words. The extra data bit is generated when a binary level transition (114) occurs in the asynchronous binary data signal. The transmission of the multiplexed data word is delayed a fixed amount of time relative to the binary level transition of the asynchronous signal to preserve the timing between transitions in the asynchronous signal. The received multiplexed data words are demultiplexed into a synchronous and asynchronous binary data signals. The demultiplexed asynchronous binary data signal emerges having transition time which is the same as the transition timing of the original asynchronous binary data signal.

Abstract: An asynchronous digital TDM multiplexer-demultiplexer combination at one communication terminal is capable of multiplexing N asynchronous input data signals having a random mixture of different bit rates into a transmitted synchronous data stream having a predetermined fixed data format and a given bit rate greater than the sum of the rates of the different rates and to demultiplex N asynchronous output data signals having the same random mixture of the different bit rates from a received synchronous data stream having the data format and the given bit rate, where N is an integer greater than 1. Each of the N channel printed circuit board plug-in receptacles, coupled to a different one of the N input data signals and a different one of N outputs each for a different one of the N output data signals, has plugged therein a selected one of no printed circuit boards, a digital data channel printed circuit board and an FSK channel printed circuit board to process a mixture of digital data signals, teletype signals and FSK signals in the N input data signals and the received data stream, with the mixture of signals being in any random order and mix and the digital channel printed circuit boards and the FSK channel printed circuit boards being plugged in the N receptacles in any random order and mix. The multiplexing and demultiplexing frame synchronization and automatic channel assignment is controlled by a programmable common controller so that the data bits of each of the N input data signals are distributed throughout the time slots of the transmitted and received data stream with equal spacing.

Abstract: An improved transmission arrangement for a color television signal includes a time-division multiplexing apparatus for alternately presenting for transmission through a single channel baseband signals defining the chrominance information of the television signal. In order to provide improved resolution, a store is coupled to the signal source for storing at a writing rate a first of the baseband components during the time at which it is generated. A read generator is coupled to the store for reading the stored baseband component at a higher data rate than that at which it was generated. The baseband component is transmitted through the single channel at the higher data rate.

Abstract: In a time division multiplexing system for multiplexing a plurality of channels having mutually-independent bit rates, the improvement wherein the pulse signals of each channel are converted into codes so that the information "1" is represented by a pulse having a width of two consecutive transmission clock periods ("0,0" or "1,1") the information "0" is represented by a pluse having a width of a single transmission clock period ("0" or "1"), and polarities of adjacent pulses are always different from each other; the pulse signals are compressed time-wise in a frame unit; and a frame synchronizing signal and a channel synchronizing signal, each consisting of marks or spaces having a duration of at least three consecutive transmission clock periods, are added to the intervals between the time-compressed frames to thereby perform time division multiplexing.

Abstract: In a system employing a plurality of touch sensitive screens which generate analog signals representing the coordinates of a position touched, a selection means is provided to select the screens rapidly in sequence with the analog output signals from the selected screen being fed to analog-to-digital converters. The sequence of selection proceeds rapidly from screen to screen until it is detected that a screen has been touched whereupon the selection sequencing pauses to permit the analog-to-digital conversion to be carried out and the resulting digital values to be read out to a computer system. Upon readout of the digital values to the computer system, the screen selection sequencing is again permitted to proceed. Means are provided to indicate whether a selected screen that is being touched was touched the last time the same screen was selected.

Abstract: Simple frequency-division multiplexing (FDM) of two television signals onto a microwave radio channel is frequently unsatisfactory because of nonlinearity-induced crosstalk from one picture into the other. With time-frequency multiplexing (TFM), two successive scan lines (or fields) of one picture are frequency multiplexed so that they can be sent in one line (or field) period. During the next time interval, two successive lines (or fields) from the other picture are transmitted, thus avoiding crosstalk between pictures. To reduce the bandwidth required, one of the two simultaneously transmitted lines (or fields) is sent as an analog differential signal. In this paper, we discuss computer simulations of these techniques with application to a 20-MHz-bandwidth microwave radio channel. Effects of filtering and nonlinearities are included insofar as possible.

Abstract: A ring scheduling apparatus for use in a digital multiplexed telephone communication system. The apparatus utilizes a controller (36) which sorts messages indicating which telephone lines are being run and what frequency and DC signal level is required for this ringing signal. The messages are sorted into voltage and frequency compatible groups. Digital data is then sent to a ring signal generating circuit (54, 42, 36, 88, 24, 66, 56, 44, 38, 26) to control the frequency of ring signal generated and the polarity of the DC signal upon which the ring signal is superimposed. A multiplexer (42, 44) and line interface circuitry for use in this system is included as well as a self-test circuit for testing the audio circuitry of idle telephone lines.

Abstract: A circuit for multiplexing a plurality of input signals to a single output signal through the use of N and P channel FETs whereby complementary switching circuitry results in a minimization of power usage in either the active or static circuit conditions This is accomplished by using a feedback technique and area sizing of the FETs to obtain optimum operational results in addition to the minimal power requirements

Abstract: A passive multiplexing system for fibre optic sensors has been implemented using SAW pulse compression filters. This approach has demonstrated a 25 dB improvement in sensitivity as compared with prior passive time domain optical multiplexing techniques.

Abstract: The equipment disclosed in the present invention provides means for SSB multiplexing and demultiplexing base-band signals, equal in number to a power of two, digital signal processing techniques. The frequency modulation process of the base-band signals is partly performed with a discrete Fourier Transform (D.F.T.), the dimension of which is appreciably reduced with respect to the number of signals to be multiplexed, and partly with modulators (multipliers), some of which are of simple construction and which are fewer in number than the number of signals to be multiplexed. Filtering is effected with a set of filters with different frequency repetition periods and which, when cascade connected, from a pass-band filter equal to the frequency band which characterizes every base-band signal. The frequency repetition period of the entire filter is equal to the sampling frequency of the multiplexed signal.

Abstract: A four-wire trunk line of a telephone network, operating with frequency-division multiplexing, is coupled by a hybrid coil to a local two-wire line and is provided, at a location separated from that hybrid coil by frequency modulators and demodulators, with an echo canceler connected across its receiving and transmitting branches. In order to eliminate frequency offset resulting from the incoherent modulation and demodulation, the echo canceler coacts with the phase-roll compensator comprising a phase-locking loop driven, during an acquisition phase, from a digital pilot-tone generator temporarily connected via a digital/analog converter to the receiving branch. The loop includes an analog/digital converter in the transmitting branch receiving the echo of the pilot tone due to hybrid-coil unbalance, a 90° phase shifter and a delay line which are connected in parallel to the output of that converter and work into respective multipliers whose output signals are summed in a digital adder, another multiplier heterodyning the adder output with the pilot tone to produce a digital beat frequency, and a function generator feeding sine and cosine functions of that beat frequency to the multipliers that are respectively coupled to the phase shifter and to the delay line. The output signals from the loop adder pass through the echo canceler, which operates on them in a working phase, to another digital/analog converter inserted in the transmitting branch. In another embodiment the tasks of the phase-roll compensator are performed by a microprogrammed processor.

Abstract: A multiplexed analog-to-digital converter is provided for use in an inertial navigation system comprising a multiplexer, a buffer, a feedback stabilized ramp generator and a comparator controlling a gated counter whose digital output is representative of the analog input signal.

Abstract: This paper describes constructions and electrical performances of shortmillimeter-wavelength quasioptical passive circuits using the Gaussian beam mode, i.e., beam mode Iaunchers, polarization-independent beam splitters, circular polarization duplexers, filters, diplexers, and multiplexer. The diplexers were devised to handle wide bandwidths with fairly low loss and to have a sharp cutoff response so that they can be applied to telecommunications systems. Experiments on these components including frequency multiplexers and antenna feed systems were carried out in the 100-GHz band. It is shown that quasioptical circuits are particular useful in reducing insertion loss of multiplexing systems for shortmillimeter wavelengths.

Abstract: Apparatus for gathering data about a plurality of chemical or physical conditions, e.g. on industrial plants utilises a plurality of passive optical sensors (93). Light for the sensors is provided by a common broadband source (90), and distributed by an optical fibre (91) from which light of a selected colour is withdrawn (92) for each sensor in turn, the colour selected for each sensor being different from that selected for the other sensors. Each colour is modified by its respective sensor as a function of changes in the conditions applied to the sensor, and all the modified colours are conveyed along a common data bus to be demultiplexed and the data displayed. The colours may be supplied by the data bus to detection means simultaneously or sequentially. Passive optical sensors (93) avoid electrical interference and incendiary risks due to electrical sparking, and colour multiplexing avoids difficulties associated with other forms of multiplexing in plant environments.

Abstract: Multiplexing means for allowing multi-octave processing of sampled data by means of a common single-octave data processor Sampled data is preselectively delayed, corresponding to delay-coding-thereof, and multiplex switching means samples the progessively delayed delay-coded data at progressively reduced data sampling rates, corresponding to lower octaves of interest In this way the several octaves of data are interleaved or time-multiplexed Similar multiplexing within the single-octave data processor corresponds to frequency multiplexing of the time-multiplexed multi-octave date, whereby the single bandwidth limit processor may handle such multiple-octave data