Importance

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Abstract

An electronic system provides traffic control and warning functions by radio transmission of signals to civilian vehicles from authorized mobile units, such as police vehicles and portable units at dangerous locations, such as the scene of an accident or road obstruction, etc., utilizing transmission within a police communications band. Transmitting circuitry carried within the mobile unit includes means for modulating the frequency modulation carrier signal radiated by an antenna with either a voice message or by preselected pulse messages. Receiving circuitry is carried within each of a plurality of civilian vehicles separate from the mobile unit, the antenna of such vehicles picking up the modulated carrier signal when the vehicle is within at least the general vicinity of the transmitting mobile unit. The receiving circuitry provides automatically selective response to the modulated carrier signal regardless of its frequency within the band and includes a demodulator and a pulse separator circuit responsive to a demodulated pulse message. A sequential switching arrangement and signalling devices interconnected with it provide visual signalling in different formats to the operator of the receiving vehicle. A further circuit is responsive also to operation of the sequential switching equipment to interconnect a transducer with the amplified output of the demodulator in response to the detection of a predetermined pulse message of a predetermined second type. Such arrangement allows the operator of the mobile unit, e.g., a policeman, to signal drivers of receiving vehicles by display of visual signals within such vehicles and also to speak directly to such drivers.

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First Claim