Abstract: A communication system uses simple microwave transmitters disposed along roadways and in-vehicle mounted receivers to transmit encoded signals to produce location-specific commercial, traffic regulatory, emergency and other information to operators of motor vehicles. An optional remote interface links transmitters to regulatory and commercial users in real-time. A microprocessor in the receiver uses the coded signals to produce messages from prerecorded messages or from message parts stored in a replaceable memory device, and to provide the messages either audibly, visually or both. The microprocessor functions under operator supplied instructions to select certain message types for display and to reject unwanted messages. The memory device is recorded in one or more languages to allow the operator to select a preferred language for message presentation.

Abstract: In a transmitter, a modulator switchably operates on one of two modes of operations, that is, in a first mode of the operation, such as an offset QPSK, FSK or .pi./4 shift QPSK, an amplitude of an output signal of the modulator does not become zero at any instant, and in a second mode of the operation, such as two-phase FSK or four-phase PSK, the output signal of the modulator is 100% amplitude-modulated or 180 phase-modulated. Second mode operation. The operation mode is switched by changing the mode of the parallel input signals to the modulator, where the parallel signals have been converted from a serial input data signal to be transmitted.

Abstract: A direct conversion receiver having a tri-phase architecture including three separate baseband signal channels. RF communications signals which are being tuned by the receiver are split into three equal and in-phase components which are mixed with three equal but substantially out-of-phase injection signals on frequency with the communications signal. The resulting baseband component signals are independently filtered and amplified on the three signal channels. The baseband components are then directed to a signal processing unit which corrects the baseband components for gain or phase mismatch errors between the signal channels based on the information carried by the three components and thereafter demodulates the signals in order to acquire the information carried by the RF communications signal. An automatic gain control system and a signal filtering system adapted for use with direct conversion receivers are also disclosed.

Abstract: A wristband with an internal antenna for a wristwatch-receiver has first and second band portions each adapted for coupling at first ends thereof to a receiver housing and an adjustable clasp for coupling opposed, second ends thereof to one another to encircle a wearer's wrist. The band portions include conductive metal strips within an insulative covering and mechanically and electrically coupled at one end to the receiver housing. The clasp is adjustably positioned on one band portion and includes a clampable/releasable conductive protrusion for electrically contacting segments of the metal strip exposed through openings in a portion of the insulative covering to form a continuous conductive loop within the wristband. The inner side of the band has a grid pattern of transverse and longitudinal ridges.

Abstract: A preset scan method for radio receivers which is capable of performing the preset scanning without producing noise and of informing the user when it is not possible to receive all of the preset radio stations. In a preset scanning method for radio receivers in which the scanning is performed, in the order of preset channels, on all of a predetermined number of radio stations that are preset according to a preset scan mode, the preset scanning method comprising the steps of: when the preset scan mode is initiated, setting a reception field strength setting to a predetermined level; and scanning the preset radio stations in the order of the preset channels to receive radio signals only from those stations having the reception field strength higher than the predetermined level for a specified period of time each.

Abstract: A diversity receiver has distributors each of which is connected with each of a plurality of antennas, and as many antenna switches as there are receivers. Each of the antenna switches has as many contacts as there are distributors. The distributor distributes a radio frequency signal from the antenna into as many signal paths as there are receivers. Each of the antenna switches is connected with each of the distributors via the contact connected with the signal path. A demodulated signal selecting circuit has as many contacts as there are said receivers. The demodulated signal selecting circuit receives the demodulated output of the receivers via each of said second contacts to selectively output the demodulated outputs of the receivers.

Abstract: A diversity control circuit which selects an optimum receiving signal in a diversity receiver and which corrects receiving signal levels in such a manner that characteristics in measuring systems for a plurality of receiving signal levels can be regarded as homogeneous. The circuit includes memory means which stores correction data and which responds to receiving signal levels to provide corrected signals conforming to a preselected characteristic.

Abstract: A handover technique in a cellular radio communication system (100) for handing over a radio (102) from a first channel in a first cell to a second channel in a second cell, the technique comprising generating a fill-in message extrapolated from a message of the radio on the first channel and communicating the fill-in message when the radio has ceased communicating on the first channel; and terminating the fill-in message when the radio begins communicating on the second channel, thereby reducing handover disruption. The messages may be digitized audio messages. A timer (110, 118) may be employed to allow the fill-in message to terminate at substantially the same time as the radio begins communicating on the second channel. Alternatively, the fill-in message may be directly terminated (FIG. 2) in response to the radio beginning to communicate on the second channel. If the messages are data messages, no fill-in message is generated and the handover is completed directly (FIG.

Abstract: A current mirror having improved turn-on and turn-off characteristics capable of operation an expanded voltage range. A cascode circuit comprising a portion of the current mirror is of a high characteristic impedance to increase thereby the voltages over which the current mirror may generate a constant current output. A switching circuit comprised of tandemly-positioned transistors having differing transistor characteristics decreases the transistor turn-on and turn-off times to enhance the characteristics of the current mirror.