Transmitter for a coded electronic security system
First Claim
1. A transmitter, usable in a security system responsive to an alarm activating event which includes a receiver capable of receiving signals from a plurality of similar transmitters, identifying the transmitter associated with each received signal in accordance with a selected pulse repetition frequency of the signal, and verifying the authenticity of each received signal in accordance with a predetermined transmission duration and transmission repetition frequency of the signal, comprising:
- (a) an RF oscillator;
(b) switching means for selectively turning the RF oscillator on and off;
(c) modulation source means for controlling said switching means, said modulation source means comprising;
(1) a first oscillator comprising an astable multivibrator for supplying output pulses having said predetermined transmission duration at said predetermined transmission frequency; and
(2) a second oscillator comprising an astable multivibrator, responsive to the output pulses of said first multivibrator, and for supplying output pulses at said selected pulse repetition frequency; and
(d) means for activating said modulation source means, said activating means including a power supply and control means for applying the voltage from said power supply to said modulation source means for a selected time after the occurrence of the alarm activating event.
0 Assignments
0 Petitions
Accused Products
Abstract
The present invention pertains to a transmitter for a coded electronic security system. The transmitter includes a modulator which automatically keys the radio frequency oscillator of the transmitter "on" and "off" to provide a pulse coded signal unique to the particular transmitter in the system. One or more remotely located receivers, of the type described herein, is adapted to receive and decode the signal generated by the transmitter of the present invention and to indicate which of the transmitters in the system has activated a signal device attached to the receiver.
-
Citations
4 Claims
-
1. A transmitter, usable in a security system responsive to an alarm activating event which includes a receiver capable of receiving signals from a plurality of similar transmitters, identifying the transmitter associated with each received signal in accordance with a selected pulse repetition frequency of the signal, and verifying the authenticity of each received signal in accordance with a predetermined transmission duration and transmission repetition frequency of the signal, comprising:
-
(a) an RF oscillator; (b) switching means for selectively turning the RF oscillator on and off; (c) modulation source means for controlling said switching means, said modulation source means comprising; (1) a first oscillator comprising an astable multivibrator for supplying output pulses having said predetermined transmission duration at said predetermined transmission frequency; and (2) a second oscillator comprising an astable multivibrator, responsive to the output pulses of said first multivibrator, and for supplying output pulses at said selected pulse repetition frequency; and (d) means for activating said modulation source means, said activating means including a power supply and control means for applying the voltage from said power supply to said modulation source means for a selected time after the occurrence of the alarm activating event. - View Dependent Claims (2, 3, 4)
-
Specification