Patent ID: 6236336
Filing Date: 2001-05-22
Classification: G08G

Abstract:
A traffic information warning system for conveying a message regarding a traffic situation from a traffic advisory site, the system comprising a transmitter adapted for placement at the advisory site and a receiver, wherein:the transmitter includes an oscillator for transmitting a first carrier signal and a second carrier signal, the first carrier signal having a first carrier frequency and the second carrier signal having a second carrier frequency, a modulator for modulating the first carrier signal with a modulating signal reflective of a traffic situation, the second carrier signal comprising an unmodulated signal, the first carrier frequency and the second carrier frequency being spaced apart by a predetermined frequency difference; andthe receiver includes scanning circuitry for scanning across a predetermined frequency range to detect carrier signals separated by the predetermined frequency difference, a demodulator for retrieving a first retrieved modulating signal about the first carrier signal, means for comparing the first retrieved modulating signal to a series of acceptable stored traffic messages and for determining whether the first retrieved modulating signal matches one of the acceptable stored traffic messages, and means for announcing a message regarding the traffic situation.