Patent ID: 6658123
Filing Date: 2003-12-02
Classification: G09B

Abstract:
A sonic relay responsive to a source of high frequency sonic pulses composed of sound at high frequencies including at least the upper frequency range of human hearing and occurring at a constant repetition rate, said sonic relay being arranged to provide low frequency sound audible to the high frequency hearing impaired and comprising:an amplifier responsive to repetitive sonic pulses composed of sound at high frequencies including at least said upper frequency range, said upper frequency range commencing at a threshold frequency above which sound is inaudible to a high frequency hearing impaired person, and arranged to provide amplified electrical signals, frequency filter means responsive to said amplified electrical signals for removing signals outside said upper frequency range and adapted to provide an output signal, logic circuit means responsive to said output signal comprising a microcontroller programmed to provide a logic output signal when the sonic pulses have the same pulse length and the pulses occur at said constant repetition rate, and a sound producer responsive to said logic output signal and adapted to provide sound predominantly at low frequencies within a frequency range of human hearing below that of said threshold frequency.