Abstract: An Emergency Vehicle Detection System having a transmitter system for use in an emergency vehicle and a receiver system for use in a non-emergency vehicle. The transmitter system generates and transmits two distinct unmodulated continuous wave signals. The receiver system detects the presence and strength of the continuous wave signals, and produces DC voltage signals which are proportional to the strength of the received continuous wave signals. The DC voltage signals are used to generate a warning signal when both DC voltage signals reach a predetermined level for a predetermined amount of time (to prevent false alarms) and maintain the warning signal for a predetermined amount of time should one of the DC voltage signals fade (fading minimization). Additionally. DC voltage signals arc used to oscillate the warning signal at a rate which is proportional to the strength of the received continuous wave signals.

Abstract: An Emergency Vehicle Detection System having a transmitter system for use in an emergency vehicle an a receiver system for use in a non-emergency vehicle. The transmitter system generates and transmits two distinct unmodulated continuous wave signals. The receiver system detects the presence and strength of the continuous wave signals, and produces DC voltage signals which are proportional to the strength of the received continuous wave signals. The DC voltage signals are used to generate a warning signal when both DC voltage signals reach a predetermined level for a predetermined amount of time (to prevent false alarms) and maintain the warning signal for a predetermined amount of time should one of the DC voltage signals fade (fading minimization). Additionally, DC voltage signals are used to oscillate the warning signal at a rate which is proportional to the strength of the received continuous wave signals.