Wireless burglar alarm system
First Claim
1. A wireless burglar alarm system comprisinga wireless transmitter, anda receiver,a first output circuit connected to said receiver and responsive to a first predetermined frequency,a second output circuit connected to said receiver and responsive to a second predetermined frequency,warning means connected to said second output circuit as a load thereof,said first output circuit being connected to said second output circuit,said transmitter being selectively operable to transmit signals having one of said first and second predetermined frequencies,said receiver being operable upon the reception of an input signal from said transmitter to produce an output signal having one of said first and second predetermined frequencies,said second output circuit being selectively operable upon the application of said output signal from said receiver at said second predetermined frequency to activate said warning means, andsaid first output circuit being operable upon the application of said output signal from said receiver at said first predetermined frequency to inhibit the operation of said second output circuit and said warning means.
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Accused Products
Abstract
A radio intrusion alarm system utilizing a high frequency carrier signal having an audio subcarrier which may be modulated by two tone signals, the first tone signal causing actuation of an alarm, the second tone signal causing actuation of a time delay means which inhibits operation of the alarm to permit an authorized entry, for example, at the transmitter location without giving the alarm.
59 Citations
49 Claims
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1. A wireless burglar alarm system comprising
a wireless transmitter, and a receiver, a first output circuit connected to said receiver and responsive to a first predetermined frequency, a second output circuit connected to said receiver and responsive to a second predetermined frequency, warning means connected to said second output circuit as a load thereof, said first output circuit being connected to said second output circuit, said transmitter being selectively operable to transmit signals having one of said first and second predetermined frequencies, said receiver being operable upon the reception of an input signal from said transmitter to produce an output signal having one of said first and second predetermined frequencies, said second output circuit being selectively operable upon the application of said output signal from said receiver at said second predetermined frequency to activate said warning means, and said first output circuit being operable upon the application of said output signal from said receiver at said first predetermined frequency to inhibit the operation of said second output circuit and said warning means.
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14. A receiver circuit assembly for use with burglar alarm systems, said assembly comprising
a receiver, a first output circuit connected to said receiver and responsive to a first predetermined frequency, a second output circuit connected to said receiver and responsive to a second predetermined frequency, warning means connected to said second output circuit as the load thereof, said receiver being operable to produce an output signal having one of said first and second predetermined frequencies upon the reception of an input signal thereto, said first output circuit being connected to said second output circuit, said second output circuit being selectively operable upon the application of said output signal from said receiver at said second predetermined frequency to activate said warning means, said first output circuit being operable upon the application of said output signal from said receiver at said first predetermined frequency to inhibit the operation of said second output circuit and said warning means, said second output circuit comprising an input stage, and an output stage, said warning means being connected as a load to said output stage, said input stage including frequency selective means to pass to said output stage substantially only those output signals from said receiver whose frequency is said second predetermined frequency, said output stage having an activated and an inactivated condition and said warning means being activated when said output stage is in its activated condition and inactivated when said output stage is in its inactivated condition, said output stage comprising a triggering device, a trigger activating switch, and a load activating switch, means connecting said input stage to said trigger activating switch, means connecting said trigger activating switch to said triggering device, means connecting said triggering device to said load activating device, means connecting said load activating device to said load, said trigger activating switch being adapted to be actuated upon the application of an output signal from said input stage at said second predetermined frequency, and actuation of said trigger activating switch actuating said triggering device and said load activating switch to thereby activate said load.
Specification