Abstract: A method and system of communicating between moving participants such that each participant is provided with a first time slice and a respective priority listing containing the name of each participant once only, each participant thus having the top priority for one first time slice only. Also allocated to each participant is a second time slice during which he must transmit his identity as well as the identities of all his near neighbors within a radius R thereof. For each participant A there is stored the identity of all near neighbors B(A) and all far neighbors C(A) being within a radius R of his near neighbors B(A) and who are not also near neighbors B(A) of A. During each first time slice, any participant having a higher priority for the respective first time slice than all of his near and far neighbors may transmit data including the identities of at least those of his near neighbors who became near neighbors since his previous transmission.

Abstract: A method of effecting handover in a mobile telephone system comprising fixed base stations and mobile stations. The system includes several layers of radio cells, where a cell in a given layer covers several cells in a nearest underlying or subordinate layer. A mobile station moving in a microcell may find it difficult to handover to another microcell in the same cell layer, when the signal strength of the established connection in the first microcell is rapidly weakened. No information concerning the target base station can be transmitted. According to the proposed method, handover is effected to a cell in the nearest overlying cell layer, a so-called umbrella cell, either permanently (the mobile is moving quickly) or temporarily (the mobile is moving slowly). In the latter case, handover is made back to a microcell. The handover command is either transmitted from the base station of the microcell having elevated power, or from the target base station.

Abstract: An adaptive digital filter uses a weight adjustment unit for adjusting the weights of an adaptive digital filter according to one or more input signals to the digital filter and according to an error signal indicative of the difference between the actual and desired outputs of the digital filter. The weight adjustment unit has a first low-pass filter for low-pass filtering a signal indicative of the product of the error signal and the one or more input signals, a squarer for squaring the output of the first low-pass filter, a second low-pass filter for low-pass filtering the output of the squarer to extract the D.C. component thereof, a third low-pass filter for low-pass filtering a signal indicative of the output of the error signal squared to extract the D.C.

Abstract: An automotive radio system employs a plurality of corrective actions in response to the detection of multipath interference to reduce distortion audible to a listener. The speed of the vehicle is determined since the number of multipath events per unit time and the expected duration of each multipath event vary according to vehicle speed. The corrective action taken in response to detection of multipath interference depends upon the vehicle speed. In a diversity antenna system, antenna switching is suspended at high vehicle speed while filtering of the audio output to reduce noise is suspended at lower vehicle speeds.

Abstract: A communications system, such as the DECT, comprises a plurality of geographically separate primary stations and a plurality of secondary stations which are able to roam relative to the primary stations. Communication between a primary and a secondary station is by way of any of a plurality of time division duplex radio channels. An idle primary station transmits an idle beacon signal. When a secondary station roams out of the coverage area of a primary station and so can longer lock to that primary station, it scans all of the radio channels for an idle beacon signal. To conserve battery power, instead of continuously rescanning all channels, the successive rescans are made less frequently as the time interval from when the secondary station was last in lock increases, until a predetermined maximum interval has been reached between successive rescans.

Abstract: A multi-user radio system, such as a trunked radio system has sets of operations ("storm plans") for execution in emergency situations. A central control and management processor is arranged to define a list of users (20) associated with a respective storm plan and to permit the defined users to execute the respective storm plan.

Abstract: A first mixer block converts received MMDS channel frequencies to MMDS frequencies capable of being processed by an MMDS decoder. The MMDS decoder, which includes a crystal controlled reference generator, is located in a benign environment. The reference is supplied to a phase locked loop for controlling a fixed frequency local oscillator that supplies the first mixer. The local oscillator output is also supplied to a second mixer that produces a response signal, of a different frequency, by biphase shift key modulation of said reference that is transmitted back to the transmitting site via the antenna. A squelch circuit precludes transmission of the unmodulated reference.

Abstract: A portable receiver provides an output of a local oscillator to a mixer for converting the received signal from an antenna to an intermediate frequency so that the intermediate frequency signal is demodulated. An oscillation generating unit outputs a low frequency signal by switching a plurality of low frequency signals in accordance with a channel designation and a dynamic phase shifter shifts a frequency of the output of the local oscillator before it is input to the mixer, by rotating the phase of the output of the local oscillator using the output signal of the oscillation generator. Therefore, the consumption of the power by this receiver can be decreased.

Abstract: A frequency converter for reception of satellite broadcasting, comprising first to fourth feeding lines, each being disposed perpendicularly to one another and vertically through the center of a patch on which a satellite signal with polarized wave components is electromagnetically focused, to allow vertically and horizontally polarized waves of the satellite signal to be excited thereat, first through fourth first-stage low noise amplifiers connected, respectively, to the first through fourth feeding lines, for blocking or transferring the vertically and horizontally polarized wave signals excited at the first through fourth feeding lines in response to a reception selection control, first and second phase shifters connected, respectively, to outputs of the first and second first-stage amplifiers, for shifting the vertically and horizontally polarized wave signals by a desired phase in response to the reception selection control, respectively, so that left and right circularly polarized waves can be generate

Abstract: An interactive multimedia system with distributed processing and storage of video picture information and associated data and sound in nodes disposed throughout a cable television distribution system. The nodes are coupled to the feeder cable of the cable distribution system. Each node in the system receives a substantially identical copy of the interactive video picture information and related data from a regional processing center. The nodes can receive the Video picture information through the cable television distribution system or externally of the cable system. The users at home televisions associated with a particular node interact directly with the video picture information in that node, rather than with the information stored in the regional processing center or some other remote location, which enables the system to quickly display photographic quality images and complex graphics, as well as sound, at the users' televisions in response to commands received by the users.

Abstract: A power amplifier used in a portable, radio frequency transmitter is switched between different modes of operation when transmitting differently modulated carriers. The first mode of operation corresponds to amplitude modulation (AM), while a second mode corresponds to angle modulation techniques such as frequency modulation (FM). A switching network alters the impedance of the power amplifier to match network for matching the impedance of the transmitter antenna in order to achieve maximum efficiency in each mode of operation. Various switching methods and impedance matching circuits are disclosed.

Abstract: A broadband radio receiver monitors transmissions over a broadband of frequencies, and especially over the aircraft band, between aircraft and control towers or between the cockpit and ground stations at an airport. The radio utilizes an earphone having a lead which provides an antenna. The lead is AC coupled to an amplifier having band-pass filters connected to the input and to output thereof to provide selectivity while passing the entire band. An AM detector is connected to the output filter and produces an audio signal which is coupled, via an RF blocking inductor, to the earphone by way of the earphone lead. A miniaturized self-contained radio is therefore provided which does not utilize a local oscillator or other radiating signal generator and may be used on board or nearby aircraft without violating regulations for the use of electronic equipment.

Abstract: A gain control circuit in which a switch is provided in series with a capacitor in a time constant circuit so that, under control of a controller, the switch is closed in its own signal reception and opened in an idle time other than the signal reception to perform gain control, whereby the capacitor can independently hold a signal reception level at the time of its own previous signal reception regardless of monitoring signal reception during the idle time.

Abstract: In a receiver an apparatus and method substantially reduces time dispersion and multipath distortion in a received signal. An equalizer (109), including taps having gain coefficients, produces an equalized signal (110) responsive to the received signal (107) and an adaptive process signal (137), wherein the gain coefficients are adjusted responsive to the adaptive process signal (137). A first mixer (111) mixes the equalized signal (110) and a reference carrier signal (115) to produce a recovered modulated signal (119). A detector (112) detects an estimate signal (129) responsive to the recovered modulated signal (119). An error signal generator (139) generates an error signal (141) responsive to a difference between the recovered modulated signal (119) and the estimate signal (129). A second mixer (147) mixes the error signal (141) and the reference carrier signal (115) to produce the adaptive process signal (137).

Abstract: A satellite communications system includes a feed array and reflector receiving antenna coupled to a dual-mode network, for generating two channels, with independent signals representing two beams, one for each channel. Each output channel of the dual-mode network contains redundant information relating to a plurality of information channels. In the absence of an interfering signal or intrusion, the combined signals are amplified and block frequency-converted, then de-multiplexed into separate channels, which are each applied through selection switches to a transmitter multiplexer for retransmission. An alternate signal is tapped from each of the two received signal channels, phase controlled, and combined, to produce a combined signal representing a receive antenna beam with a null controllable in position in response to phase. The combined signal is demultiplexed into separate information channels.

Abstract: A method and apparatus whereby a communication unit (10) transmits a first communication channel request signal at a first power level. If a communication link with a base site (12) is not established within a predetermined period, the communication unit transmits a second communication channel request signal at a second level which is higher than the level of the first communication channel request signal. This process may be continued for a predetermined number of times or until a communication link is established. Thus, the probability that a nearby base site, rather than a more distant base site, grants the communication channel is greatly enhanced.

Abstract: An interactive television system where interactive information is inserted in the vertical blanking interval of a standard television signal. The signal is received and decoded by a stetop decoder which sends the decoded signal via an infrared signal to a handheld device. The viewer using the handheld device can interact with a game, sports, or education event or other presentation on the television. The system includes a proprietary high level command language and programmer (PIU) tables which are maintained in the memory of the handheld device. The PIU tables store the transactions of the various events presented on the television. The transactions are sent from the insertion system to the decoder throughout the broadcast of the television program.

Abstract: A communications device is disclosed for use between a CATV distribution line and a plurality of CATV subscribed premises for monitoring the utilization of each subscriber of a plurality of subscribers of TV channels distributed over the CATV distribution line. The devise comprises a subscriber status monitor associated with each subscriber premises of the plurality of subscribers for connection to the distribution line and delivering one or more of the TV channels to the associated subscriber.

Abstract: A receiver includes a plurality of antennas, a selection switching unit for selectively switching between the plurality of antennas to output one of the respective output signals of the plurality of antennas having the largest induced voltage, and a unit for converting the selected one antenna output signal to an audio signal to be outputted as an output signal of the receiver. The receiver further includes a muting control unit for detecting the level of the induced voltage of the selected antenna output signal so as to output a muting control signal when the detected level of the induced voltage becomes smaller than a predetermined value, and a muting unit for muting the audio signal for a predetermined time on the basis of the muting control signal. The selection switching unit performs its antenna switching operation on the basis of the muting control signal.

Abstract: A portable radio provided with a slidable antenna retractably supported by a housing, an antenna operating member movably mounted in the housing for projecting an antenna top portion from the housing by sliding the antenna in a first direction toward the outside of the housing or for releasing the antenna to enable the antenna to slide in a retracting direction opposite to the first direction, and an operating portion for operating the antenna operating member from outside the housing.