Abstract: A computer network comprising a plurality of nodes, each coupled to a DTE device comprising a computing system and a remotely located human interface, which includes a display and at least one I/O device. The DTE device computing systems are commonly located. Each DTE device includes an encoder coupled to the computing system, a decoder coupled to the display and the at least one I/O device, and a transmission line coupling the encoder and the decoder. The encoder receives, from the computing system, a video signal for transmission to the display and a non-video signal for transmission to the at least one I/O device, encodes the video and the non-video signals, and transmits the encoded signals to the decoder via the transmission line. The decoder receives the encoded signals, and decodes the video and non-video signals therefrom for respective propagation to the display and the at least one I/O device.

Abstract: A technique for amplitude modulating a carrier without producing side-bands is disclosed. In a preferred embodiment, a signal carrier is directly modulated and no energy side-bands are produced. This is accomplished by amplitude quantizing the data or information to be transmitted at the carrier rate or frequency and then resetting the amplitude of the carrier during one of the two 0-crossing times for each cycle of the carrier.

Abstract: Method and apparatus for facilitating the simultaneous bi-directional transmission of data on a single AM carrier is described. In particular, the process is implemented using two or more transceivers, each comprising a modulator, a demodulator, and an oscillator operating at the same frequency and in locked phase. One of the oscillators functions as a master, to which all other oscillators ("slaves") are locked. Each of the transceivers also includes means for recovering the appropriate signal to be demodulated by the particular transceiver.

Abstract: A computer network having multiple remotely located human interfaces which share a common computing system which appears, to each of the human interfaces, as a virtual computer dedicated to that human interface. The computer network includes a processor subsystem and a plurality of nodes, each coupled to the processor subsystem and having a remotely located human interface comprised of a video monitor and an I/O device coupled thereto. Each one of the nodes further incudes a first interface device coupled to the processor subsystem and to a transmission line while each of the human interfaces further includes a second interface device coupled to the video monitor, the I/O device and the transmission line. The computer network further includes a memory subsystem coupled to the processor subsystem and having a plurality of memory areas, each corresponding to one of the plurality of nodes.

Abstract: A computer comprised of a computing system positioned at a first location and a human interface, which includes a video monitor, and plural I/O devices, specifically, a keyboard, mouse and printer, positioned at a second location remotely located relative to the first location. The computer further includes a first encoder coupled to the computer system, a first decoder coupled to the video monitor and the at least one I/O device and a transmission line which couples the encoder to the decoder. The first encoder receives, from the computing system, a video signal to be transmitted to the video monitor and a non-video signal to be transmitted to the at least one I/O device. The first encoder combines the video and the non-video signals into a combined signal and transmits the combined signal to the first decoder via the transmission line.

Abstract: A technique for encoding multiple digital data streams in a limited bandwidth for transmission in a single medium is described. A pulse tuned to an assigned frequency is generated each time a data stream makes a transition. The polarity of each pulse represents the direction of the corresponding transition. In one aspect, a different length pulse is assigned to each incoming data stream to be encoded such that each incoming data stream will generate pulses of different length, thus occupying a different part of the frequency spectrum. These different pulse lengths create a group of "channels" each representing the activities of a different data stream. in each case, the length of the data pulse is shorter than the length of the fastest individual bit to be processed. The pulses are then summed in an analog summer and transmitted as the new, combined data stream.

Abstract: Method and apparatus for processing an analog signal comprising one or more digital data streams encoded as a series of pulses is described. In a preferred embodiment, the analog signal is input to a mixer for mixing the signal with a signal of a local oscillator frequency to increase the frequency of the analog signal. The signal output from the mixer is applied to a narrow band filter such that a series of pulses is output from the filter when a signal of the frequency to which the filter is tuned is applied to the filter. The pulses are detected by a wave shaper, which uses them to identify the presence of a bit transition in the encoded data stream represented by the series of pulses. The wave shaper determines the polarity of the pulse, that is, whether it is positive or negative, which indicates whether the corresponding transition of the encoded data stream is positive or negative, respectively, then uses this information to reconstruct each digital bit, and hence the entire data stream.

Abstract: A computer network comprised of a plurality of interconnected nodes, each having a DTE device coupled thereto. Plural ones of the DTE devices are each further comprised of a computing system positioned at a first location and a human interface, which includes a video monitor, and plural I/O devices, specifically, a keyboard, mouse and printer, positioned at a second location remotely located relative to the first location. The first locations at which the computing systems of the DTE devices are positioned are commonly located. The DTE devices further include a first encoder coupled to the computing system, a first decoder coupled to the video monitor and the at least one I/O device and a transmission line which couples the encoder to the decoder. The first encoder receives, from the computing system, a video signal to be transmitted to the video monitor and a non-video signal to be transmitted to the at least one I/O device.

Abstract: A narrow band-pass interferometric filter for applying a response characteristic to an input signal to produce a filtered output signal. The filter is comprised of an inverting amplifier having an amplifying input to which the input signal is applied, an inverting input and an output. Coupled between the output and the inverting input of the inverting amplifier is an interferometric processing circuit which produces a signal having a generally constant positive amplitude except for a null at a pass frequency of the response characteristic for the filter. As the inversion of the signal produced by the signal processing circuit is the response characteristic of the filter and the amplitude thereof is greater than the amplitude of the input signal, the inverting amplifier passes the input signal whenever the frequency of the input signal matches the pass frequency of the filter.

Abstract: Method and apparatus for enabling the transmission of high bandwidth analog and digital data over cable lengths of more than 1000 feet through low cost semishielded or unshielded four wire cable are disclosed. Three balanced mode signals are transmitted using four conductors. In this configuration, the components A+ and A- of a first balanced mode signal A are respectively carried on a first pair of conductors, the components B+ and B- of a second balanced mode signal B are respectively carried on a second pair of conductors, and the components C+ and C- of a third balanced mode signal C are respectively carried on a pair of conductors synthesized through the commonality of the first and second conductor pairs, respectively. Using this technique, a new additional virtual ground plane is created wherein signal energy can be transmitted without interfering or combining with the other signals being transmitted on the remaining conductor pairs.

Abstract: Video data transmission and display system configured for transmitting three video data signals and two synchronization signals over three lines while preserving polarity information for the synchronization signals. The system includes a video encoder which combines the R video signal and the HSYNC synchronization signal into a first video/synchronization composite signal and combines the B video signal and the VSYNC synchronization signal into a second video/synchronization composite signals. The two video/synchronization composite signals are transmitted, together with the G video signal, over respective ones of three transmission lines to a video monitor. The video monitor includes a video decoder which separates the original video and synchronization signals from each of the video/synchronization composite signals.