Patent ID: 7245232
Filing Date: 2007-07-17
Classification: G08G

Abstract:
1. An apparatus to detect selected sound frequency signals emitted by warning devices of vehicles comprising: a sensor to sense a selected sound frequency signal spectrum in communication with a plurality of operational amplifiers that are in communication with a warning indicator wherein said plurality of operational amplifiers comprising: a first operational amplifier biased to detect a low frequency signal spectrum within approximately 50 feet of a warning device sound source; a second operational amplifier biased to detect said low frequency signal of said selected sound frequency signal spectrum within approximately 1,500 feet of said warning device sound source; a third operational amplifier biased to detect a high frequency signal of said selected sound frequency signal spectrum within approximately 50 feet of said warning device sound source; a fourth operational amplifier biased to detect said high frequency signal of said selected sound frequency signal spectrum within approximately 1,500 feet of said warning device sound source; and said plurality of operational amplifiers upon detecting said warning device sound source activate said warning indicator.