Abstract: System and method utilizing the temporal separation and amplitude differences of signals for transmitting the signals in a bandwidth corresponding to one half of the frequency range present in the signals.

Abstract: An emergency roadside telephone system includes a plurality of self-powered, emergency telephone terminals positioned at remote locations, such as along roadways, to permit communication with a central station in order to obtain emergency assistance. Each emergency telephone terminal has a transmitter and a receiver for communication with the central station, a handset for providing voice communication and a plurality of emergency switches carrying symbols representative of various types of emergency assistance required such that a caller can request emergency assistance either by voice communication with an operator at the central station or, if there is a language barrier, by actuating the emergency switches.

Abstract: A radio control system having a radio-controlled model toy on which a d-c power supply, a receiver and two electric motors are mounted, and a transmitter for maneuvering the radio-controlled model toy, and characterized in that the transmitter is constructed so that a control pulse signal having a pulse level representing signal "1" and a pulse level representing signal "0" is transmitted and the duration of the signal "1" pulses is increased or decreased, and that the receiver is constructed so that driving current is supplied to a motor during the signal "1" pulse duration and to another motor during the signal "0" pulse duration.

Abstract: A base station encoder is connected to a decoder terminal and paging transmitter by means of a single voice-pair telephone line link. Automatic operations reduce operator fatigue and operating costs. Digital, tone-keyed gain controls automatically compensate for line losses. All dialing, including long distance and overseas calls, and station identification are done automatically.

Abstract: In an FM stereo demodulator, a detector circuit for detecting a low supply voltage is used. The detection level of this detector circuit is made substantially equal to a supply voltage value at the time when the oscillation frequency of an oscillator circuit for reproducing a subcarrier signal begins to change. The stereo reproduction of the demodulator is compulsorily switched to monaural reproduction by an output from the detector circuit. As a result, the generation of an abnormal sound which is attributed to the beat between the reproduced subcarrier signal having fluctuated and a subcarrier signal component of a received broadcast signal is prevented.

Abstract: A demodulation circuit for an FM stereo receiver is constructed to invert the FM stereo composite signal by an inverting amplifier and then to supply the inverted signal to a switching circuit for producing demodulated left and right signals. The composite signal is applied to a phase-locked loop circuit for applying a 38 kHz switching signal to the switching circuit. A 19 kHz signal produced by the phase-locked loop circuit is converted into a sine wave signal by a waveform converting circuit. The sine wave signal is converted into a direct current signal which is applied to one input of a level comparator having the other input connected to receive the 19 kHz pilot signal extracted from the composite signal. The output of the comparator is sent to a level control circuit which controls the level of the signal supplied to the input of the inverting amplifier. Accordingly, the pilot signal is canceled in the signal sent to the switching circuit.

Abstract: In a mobile telephone system of the type in which the service area of the system is divided into a plurality of radio zones, mobile-system base stations are installed in respective radio zones, each mobile-system base station is connected to a mobile-system control unit through a common control channel and a plurality of speech channels, and the mobile-system control unit is connected to an existing telephone network via a mobile-system exchange unit, there are provided signal lines extending between the mobile-system base stations and the mobile-system control unit and between the mobile-system control unit and the mobile-system exchange unit and respectively combined with each of the speech channels. These signal lines are used to determine the state of the speech channels, and to transmit control and information signals.

Abstract: A flexible acoustic coupler includes a pair of muffs and at least one acoustic-electrical transducer located in one of the muffs. Each of the muffs is arranged to support either the mouthpiece or earpiece of a conventional telephone handset. The muffs, in turn, are joined by a flexible coupling element which normally supports the muffs spaced apart so as to be mated in acoustic coupling relation with a conventional telephone handset. The flexible coupling element, however, is capable of flexing so that one muff can be rotated 180.degree. with respect to the other muff and mated therewith to thereby reduce the space taken up by the coupler when not operating. In implementation, the flexible coupling element and both muffs are integrally molded providing an attractive and efficient low cost acoustic coupler.

Abstract: This telephone earphone amplifier is turned on automatically when the telephone handset is taken off-hook. To this end, the dc bias provided to the microphone from the telephone line is used to turn on a semiconductor switch that connects dc power to the amplifier. The amplifier itself is connected to amplify the incoming audio, so as to provide greater volume e.g., to aid persons of impaired hearing.

Abstract: The local battery and elements of a booster circuit of the energy storage-energy discharge type of swinging choke power converter are connected in series in the subscriber's local battery loop of a carrier subscriber station terminal. A smoothing capacitor is connected across the battery and booster circuit elements for providing a loop voltage there that may be greater than a local battery voltage where a subscriber Touch-Tone telephone set is off-hook and sending calling signals. Current in the circuit elements is monitored for controlling the duration of the portion of a cycle of operation of the converter during which energy is stored by the choke and, thus, maximum current drain from the battery. In an alternate embodiment, the smoothing capacitor is connected across only circuit elements.

Abstract: A telephone handset acoustic coupling cup adapted for use as part of an acoustic data coupler wherein the cup has a flexible, gripping lip surrounding an opening for receiving a telephone handset transmitter or receiver case. Each of two acoustic coupling cups may additionally be eccentrically rotatably mounted on a case in a manner that their openings may be varied in distance from one another by rotating the cups with respect to the case. The cups may also be flexible in a manner to be bendable with respect to said case, all with the view of providing an acoustic data coupler that can accept a wide variety of different sizes and shapes of telephone handsets.

Abstract: A noise blanker circuit for a stereo radio receiver is disclosed herein. The noise blanker circuit detects noise impulses in a received radio signal. When the magnitudes of these detected noise impulses exceed a predetermined threshold level corresponding noise blanking pulses are produced which are coupled to a gate means. The gate means receives the received radio signal and selectively passes and blocks this signal in response to the noise blanking pulses such that the output of the gate means is essentially free of noise impulses. A manually adjusted actuator is provided for selectively altering the predetermined threshold level of the noise blanker circuit such that the most efficient mode of noise blanking can be implemented. In addition, rate shut-off circuitry is provided to prevent the production of noise blanking pulses when the detected noise impluses occur at a repetition rate exceeding a maximum repetition rate.

Abstract: Apparatus and methods relating to "quadrasonic" encoding and decoding systems, including synthetic supplementary channel systems, matrix logic systems, and systems employing stereo compatible matrix variations.

Abstract: A ringer-power generator circuit is provided in which ring pulses cause positive and negative output voltages of a swinging choke regulator to be alternately connected to one of the tip and ring lines of a handset; and cause a control circuit to be alternately connected to and disconnected from a supply voltage. The control circuit has an RC timing circuit which delays initial turn on of the regulator to prevent bell tapping, and includes a transistor, diodes and timing circuit which control maximum output power and maximum output voltage of the regulator for causing the latter to essentially operate as a voltage limited high impedance source.

Abstract: A utility meter in a dwelling or the like is read from a main station through a transmission line. A reverse current blocking diode is provided in the transmission line. Interphones for voice communication are connected to the transmission line at the meter and main station. A bias voltage source forward biases the diode to enable voice communication.

Abstract: Apparatus and methods relating to "quadrasonic" encoding and decoding systems, including synthetic supplementary channel systems, matrix logic systems, and systems employing stereo compatible matrix variations.

Abstract: The disclosure is of facsimile apparatus having support means for holding a telephone handset during operation of the machine in receiving or transmitting a message. This means comprises a seat of rubber on which the handset rests, and, in addition, a ring of smooth material on which the handset slides as it is brought into engagement with the support means and as it is slipped into its operating position with respect to the support means. The apparatus also includes a novel, spring support arrangement for the handset support.

Abstract: A controller at a monitor location generates interrogate signals which are transmitted over a telephone line to a transmitting unit associated with a plurality of underground gasoline storage tanks. The transmitting unit responds to the interrogate signals to selectively couple pressure sensing lines to a pressure sensing transducer. Each line extends into a different one of the storage tanks and provides a pressure which is proportional to the depth of the liquid in the corresponding tank. As each line is coupled to the transducer in sequence, the transducer provides an output voltage corresponding to the sensed pressure. The output voltage controls a transmitter of the transmitting unit which generates an audio signal related in frequency to the sensed pressure, and the frequency signal is transmitted over the telephone line to the controller which detects and decodes the frequency signal and controls a display unit to provide a visual display of the liquid level in the selected tank.

Abstract: In a carrier subscriber terminal, a voltage regulator converts the line voltage to a relatively uniform operating voltage for driving a power converter that charges a local battery. The control circuit for the converter comprises a programmable unijunction transistor (PUT) Q1 having a gate and anode connected to intermediate points of associated pairs of resistors R1-R2 and R3-R4 that are electrically connected across the line, and having a cathode connected through a first capacitor C1 and associated discharge path to one side of the line. A Zener diode D5 is resistively connected across the line to establish a reference voltage which is connected through a first diode D1 to the PUT anode, through second and third diodes D2 and D3 to the PUT gate, and through only the second diode D2 to a second capacitor C2 of the regulator.

Abstract: The service area of the system is divided into a plurality of overlapping radio zones and a mobile-system base station is installed in each zone. The mobile-system base stations are assigned with a common control channel and each station is assigned with a plurality of speech channels which are commonly controlled by the control channel. Where a mobile body originates a transmission, the intensities of signals received by respective stations which have resulted from a signal transmitted by the mobile body are compared so as to designate an idle speech channel of a station which has received a signal having the maximum intensity among mobile-system base stations including the idle speech channel.