Sound responsive intruder detection circuit

Claim 1

SIGNAL DISCRIMINATING APPARATUS COMPRISING, A SOURCE OF A COMMON MODULATING SIGNAL, FIRST AND SECOND INPUT TERMINALS FOR RECEIVING FIRST AND SECOND INPUT SIGNALS RESPECTIVELY, FIRST AND SECOND MODULATING MEANS COUPLED JOINTLY TO SAID COMMON MODULATING SIGNAL SOURCE AND RESPECTIVELY TO SAID FIRST AND SECOND INPUT TERMINALS FOR MODULATING SAID FIRST AND SECOND INPUT SIGNALS RESPECTIVELY WITH SAID COMMON MODULATING SIGNAL TO PROVIDE FIRST AND SECOND MODULATED OUTPUT SIGNALS RESPECTIVELY, MEANS FOR VARYING THE FREQUENCY OF SAID COMMON MODULATING SIGNAL OVER A PRESCRIBED FREQUENCY RANGE BETWEEN AN UPPER LIMIT FREQUENCY AND A LOWER LIMIT FREQUENCY, FIRST AND SECOND DETECTING MEANS FOR DETECTING SPECTRAL COMPONENTS CENTERED ABOUT A PREDETERMINED FREQUENCY, FIRST AND SECOND SELECTIVE TRANSMISSION MEANS COUPLED TO SAID FIRST AND SECOND MODULATING MEANS RESPECTIVELY FOR TRANSMITTING SPECTRAL COMPONENTS OF SAID FIRST AND SECOND MODULATED OUTPUT SIGNALS RESPECTIVELY CENTERED ABOUT SAID PREDETERMINED FREQUENCY TO SAID FIRST AND SECOND DETECTING MEANS RESPECTIVELY, AND GATING MEANS COUPLED TO THE OUTPUTS OF SAID FIRST AND SECOND DETECTING MEANS FOR INHIBITING THE TRANSMISSION OF A SIGNAL FROM SAID FIRST DETECTING MEANS WHEN SAID FIRST AND SECOND SELECTIVE TRANSMISSION MEANS ARE SIMULTANEOUSLY TRANSMITTING SPECTRAL COMPONENTS OF SAID PREDETERMINED FREQUENCY.