Abstract: A unique digital compression technology for increasing the information carrying capacity of a bandwidth limited communications path highway by using a combined coding and modulation technique. The inventive technology allows multiple independent modulated data streams to simultaneously and instantaneously share the same bandwidth without cross-channel interference. A matched filter is used to substantially reduce the error rate and utilizes a unique training method based on performing a spectral response test. An algorithm calculates the effect of the unique characteristics of the communications highway on the transmitted signal and generates an ideal signal stored in the matched filter for comparison with received signals.

Abstract: A unique digital compression technology for increasing the information carrying capacity of a bandwidth limited communications path highway by using a combined coding and modulation technique. The inventive technology allows multiple independent modulated data streams to simultaneously and instantaneously share the same bandwidth without cross-channel interference. A matched filter is used to substantially reduce the error rate and utilizes a unique training method based on performing a spectral response test. An algorithm calculates the effect of the unique characteristics of the communications highway on the transmitted signal and generates an ideal signal stored in the matched filter for comparison with received signals.

Abstract: A unique digital compression technology for increasing the information carrying capacity of a bandwidth limited communications path highway by using a combined coding and modulation technique. The inventive technology allows multiple independent modulated data streams to simultaneously and instantaneously share the same bandwidth without cross-channel interference. A matched filter is used to substantially reduce the error rate and utilizes a unique training method based on performing a spectral response test. An algorithm calculates the effect of the unique characteristics of the communications highway on the transmitted signal and generates an ideal signal stored in the matched filter for comparison with received signals.

Abstract: A digital compression system including a superresonant filter, which adds samples of a digital data signal at a frequency to previous samples. The added samples are parts of sine or cosine waves, not the sum of the waves. The output signal is actually the summation of the samples. The samples are made during at most a single period. The disclosed superresonant filter has a settling time significantly faster than prior art narrow band filters. Prior art narrow band filters passing approximately 1 Hz require approximately 1 second to settle. The disclosed superresonant filter passing 1 Hz will settle in approximately 1 microsecond.

Abstract: A digital compression system including a superresonant filter, which adds samples of a digital data signal at a frequency to previous samples. The added samples are parts of sine or cosine waves, not the sum of the waves. The output signal is actually the summation of the samples. The samples are made during at most a single period.

Abstract: This invention describes a compressive method of transmitting digital information. Parallel communication branches are coded to transmit ensembles of bits coded so that they can be added together and forwarded over a single transmitted channel without interference. Decoding occurs at a receiving station. In accordance with the invention an iterative method of modulating multiple simultaneous signals is accomplished, so that multiple closely spaced signals can pass through a narrow bandpass filter, where the bandwidth of the communications highway connecting a transmit and receive station is determined by the communication bit rate of the simultaneous bit ensemble. The invention is also advantageously applicable to a compressive digital storage system.

Abstract: An improved coding system for digital transmission compression applicable as a digital compression algorithm for increasing the bandwidth of telecommunications and broadcasting networks. The improved coding system operates in the transmission regime, not in baseband (source) so that a transmission channel having a capacity of 1 Mbit/s can deliver N Mbit/s, where N bits in parallel are combined to be delivered in the 1 Mbit/s channel.

Abstract: A cooperating communications system in which at least two stations and a connecting communications link form a cooperative communicating loop. Each station contains a plurality of amplification stages, which stages are selected by binary input messages. An oscillating loop is established in response to the selection of a predetermined number of amplification stages. The oscillating loop permits the occurrence of secure communication between the two stations.

Abstract: An authentication system in which communication between two locations is provided by a continuous full duplex bidirectional communications highway, which highway is a secure link between the two locations. Each location transmits information to the opposite location on a bit-by-bit basis, with a previously transmitted bit of information serving as a decoding key for the most recently received bit of information and said received bit in turn serving as the encoding key for the next bit to be transmitted. An authenticated transaction record is provided upon receipt of verified transactional data, and the reception of remotely received information may be authenticated to the sender of such data.

Abstract: The method and apparatus of the invention described herein provide confidential communications between two or more stations whereby the exchanged messages themselves provide the necessary enciphering keys for the messages to be encrypted and transmitted from each respective station. A full duplex communications loop is utilized between stations and the messages are exchanged substantially simultaneously.

Abstract: A digital multiplexer accommodates a large number of information signal channels per digital transmission channel through use of an improved statistical coding technique and successive frame transmission, the technique being based on channel designation and channel code permatation. The information signals are encoded into transmission code words, the code words are ordered into successive transmission frames and the transmission frames are sent over a communications highway to a remote location.

Abstract: A communications system and network wherein communications links between subscribers are established by retrodirective oscillating loops between each subscriber and a node station. Provision is also made for establishment of retrodirective oscillating loops between nodes so that remotely located subscribers can communicate. Information is transmitted between subscribers by using a mixing process in the node whereby information transmitted from one subscriber to a node is transferred to a carrier signal transmitted between nodes or between a second node and another subscriber. A sampling technique is also described for use in the node which greatly minimizes the amount of apparatus required to implement the mixing process.

Abstract: A digital multiplexer accommodates a large number of voice channels per digital channel through use of an improved statistical coding technique. Analog information on the voice channels is encoded into multibit digital words by PCM encoders and the bit position at the output of each PCM encoder is staggered such that a predetermined bit in each word is presented at different times to encoder outputs. The multibit digital words are converted to multibit digital code words and the code words are in turn converted into a PAM signal for transmission over a communications highway. Bit staggering advantageously allows the use of a minimum number of PAM signal levels in comparison to prior art techniques.

Abstract: A communications system and network wherein communications links between subscribers are established by retrodirective oscillating loops between each subscriber and a node station. Provision is also made for establishment of links between nodes so that remotely located subscribers can communicate. Information is transmitted between subscribers by using a mixing process in the node whereby information transmitted from one subscriber to the node is transferred at the node to a carrier signal transmitted between the node and another subscriber.

Abstract: A transponder for use in a communication system for receiving and transmitting electro-magnetic signals, includes a first antenna array operative for receiving a first signal from a first direction and transmitting a second signal, a second antenna array operative for transmitting the second signal in a second direction, and a signal processor coupling the first and second antenna arrays to each other and being operative for receiving the first signal from the first antenna array, for phase shifting the first signal to the second signal, for coupling the second signal to the first antenna array to produce a first transmitted signal possessing a relative null in the radiated electro-magnetic power density distribution in the first direction, and for coupling the second signal to the second antenna array to produce the second transmitted signal possessing a relative maximum in the radiated spatial electro-magnetic power density in the second direction.

Abstract: In an electronic system for use in a communication system wherein there is radiated a plurality of information carrying electromagnetic first signals each having a radiating source and each having a radiated electromagnetic first reference signal, a transponder operable for receiving all of the electromagnetic signals and for radiating in response thereto a plurality of information carrying electromagnetic second signals corresponding respectively in information content to the first signals and a plurality of electromagnetic second reference signals corresponding respectively to the first reference signals, the transponder comprising a plurality of first antenna means each having output means and each operable for receiving the first signals and the first reference signals and for producing in response thereto a set of corresponding transmission line signals at its output means, and transmission means coupled to the output means of all of the first antenna means and operable for producing from the sets of tra