Abstract: To improve reliability of recognition of an announcement recognition (AR) signal radiated by a transmitter upon broadcasting an announcement (e.g. traffic information, news, etc.), in the form of AM modulation of a 57 kHz auxiliary subcarrier, in which the subcarrier may also be modulated by other control signals, the subcarrier is filtered in the receiver, demodulated, and the degree of all modulations, regardless of frequency, on the subcarrier is sensed, and if the modulation changes significantly, for example rises from 60% modulation to 90% modulation (50% change), a switch (4) is activated which inhibits transmission of audio programs from an external source, such as a tape recorder (5), tuner tuned to another station, or the like, and reproduces the announcement being broadcast; termination of the AR signal, forming the AR modulation on the subcarrier, causes the switch to revert for reproduction of previously controlled audio information.

Abstract: Automobile radio - cassette combination which includes a special announcement decoder, for example to decode traffic announcements and the like. To shield passengers in an automotive vehicle from additionally listening to announcements, while permitting passengers to continue to listen to recorded programs on a tape, for example, while permitting the operator to listen to traffic announcements, the switching network of the radio with the announcement feature is expanded, and coupled with a selector switch permitting, selectively, operation of:(a) earphone reproducing cassette; loudspeaker muted, automatic announcement reproduction maintained;(b) earphones reproduce radio program, loudspeaker muted, automatic announcement reproduction via loudspeaker maintained;(c) earphone reproduces cassette, loudspeaker reproduces radio program, including announcements;(d) loudspeaker reproduces cassette program, radio muted.

Abstract: A radio paging receiver having two power sources, a receiver, a decoder and an oscillator, provides power from the lower of the two voltage sources to the oscillator when the paging receiver is turned off and provides power from the higher of the two voltage sources to the oscillator when the paging receiver is turned on. The oscillator provides higher power pulses to the decoder immediately upon the turn on of the pager thereby providing an immediate normal tone sound from the paging receiver.

Abstract: Warning-signal producing apparatus and system for a first motor vehicle responsive to a vehicle-presence-indicating radio wave signal produced by and emitted from a second motor vehicle within a certain distance of the first motor vehicle for effectively causing the production of a corresponding warning signal within the interior of the first motor vehicle and, in one form, for correspondingly attenuating, muting, or interrupting sound emitted by any simultaneously operating intertainment apparatus within the first-mentioned-motor vehicle.

Abstract: A pulse generator is provided for transmitting individual acoustic pulses which can be sensed by an audio surveillance device and retransmitted as modulated electromagnetic information. Circuitry is associated with the pulse generator for controlling the time when a first acoustic pulse is generated relative to the detection of an unmodulated carrier frequency. This circuitry further provides for the generation of a second acoustic pulse in the event that a modulated carrier frequency is detected during the interval when it can be expected that the first pulse has resulted in modulation of the previously unmodulated carrier frequency. Means are included in the circuitry for comparing the respective periods between the times the first and second acoustic pulses are generated and when modulation on the carrier frequency occurs within the predetermined intervals following such pulse generations.

Abstract: An attention signal receiver in which emergency broadcast transmissions are detected from various locations. A scanning circuit sequentially activates means to produce a plurality of oscillating frequencies which mix or beat with the incoming r.f. signals. An attention signal is a two tone signal that includes both a 960 H.sub.z frequency signal and a 853 H.sub.z frequency signal. The audio stage of the receiver is connected to a two tone decoder that passes only a 960 H.sub.z signal and a 853 H.sub.z signal. A squelch circuit is also connected to the audio stage of the receiver. Connected to the output of the tone decoder is a one second time delay circuit and a ten second time delay circuit. If an attention signal is detected for a period of time in excess of 1 second, the one second time delay circuit stops the scanning of the scanning circuit to lock in the receiver to the first carrier detected with an attention signal. The ten second time delay circuit normally disables the squelching circuit.

Abstract: A paging receiver is provided having an information setter that includes a memory device for storing call numbers assigned the receiver to enable it to determine when it has been individually selected by a radio paging message. In addition to the call numbers, the memory device also stores receiver performance information which selects which of several possible means are used to indicate that a message has been received. A decoder, preferably in the form of a microprocessor, stores information contained by the information setter in a separate register or memory device contained in the decoder. Once the information has been read from the information setter into the decoder it effects control of the receiver's receiving operation, as well as the receiver's selective response to paging messages.

Abstract: A radio controller for radio control of model vehicles and the like. The controller can be placed in a control mode wherein vehicle functions such as motor speed, direction, horn and lights are controlled by control signals. In addition, the controller can be placed in a voice transmission mode wherein an audio signal is transmitted to the vehicle and broadcast from a speaker mounted on the vehicle. The receiver of the radio controller is switched from the control mode to the voice transmission mode by way of the control signals. When the receiver is placed in the voice transmission mode, the control signals are ignored with switching to the control mode being accomplished by receiver circuitry which detects a momentary absence of the transmitted carrier signal.

Abstract: A selective calling receiver has a receiver section for receiving and demodulating radio signals. A decoder section, which is connected to the receiver section, operates with first and second levels of power consumption for selectively receiving the demodulated signals and controlling the receiving operation. A voltage converter section is switched off responsive to a signal from the decoder section when the circuit is operational at the first level of power consumption. The voltage converter section is intermittently switched on and off when the circuit is operating, which requires the second level of power consumption. A timer is activating within a predetermined period after the power is switched to the second level.

Abstract: A compact radar detector incorporates an elongated dielectric antenna, one end of which is coupled to an aligned cylindrical resonant waveguide. The dielectric antenna has cylindrical and tapered portions which cooperate with the waveguide to provide a narrower beam width, high gain and more directivity in comparison to prior art radar detectors. The antenna projects forwardly from a relatively thin rectangular housing which encloses the waveguide and other components in a manner providing for convenient and efficient assembly.

Abstract: A pulse generator is provided for transmitting an acoustic pulse which is sensed by an audio surveillance device and retransmitted as modulated electromagnetic information. Associated with the pulse generator is a timing arrangement and display. The timer is triggered into operation by the generation of the acoustic pulse. The operating speed of the timer is established to be a function of the speed of sound. Means are provided to stop the timer upon receipt of a demodulated signal representative of the retransmitted pulse whereby the display indicates the distance to the surveillance device.

Abstract: A superheterodyne radio receiver which is simultaneously tuned to receive both signals selectively tuned within the general AM broadcast spectrum and signals transmitted at the intermediate frequency, as defined in the receiver. The receiver responds to predetermined coded signals on the broadcast intermediate frequency signal to inhibit the local oscillator in preference to subsequent information broadcast on the intermediate frequency.

Abstract: Two semiconductor diodes are serially interconnected across a ratio detector in the same polarity. When the detected output from the ratio detector reaches a predetermined magnitude, both diodes are conducting and the detected output is taken from the junction of the diodes. When the detected output from the ratio detector falls due to a lower received signal level, an increase in noise level is ordinarily experienced. Because the output of the ratio detector is lower, the diodes are no longer fully conductive. This causes an increase in output impedance and a corresponding reduction in noise output.