Alarm system

Claim 2

An alarm system comprising a plurality of heads each including transducer means detecting disturbances and generating signals upon detection thereof and evaluating means connected to said transducer means to receive said signals and generate an output pulse in response to such of said signals as are indicative of the occurrence of an alien disturbance; and circuit means connected to said heads to receive output pulses therefrom and initiate an alarm in response to an output pulse from any one of said heads.

Claim 3

A system as claimed in claim 1 in which each of said heads generates said output pulse in response to a selected number of signals within a selected period of time.

Claim 4

A system as claimed in claim 2 in which each of said heads generates an output pulse in response to a signal having a duration greater than a selected period of time.

Claim 5

A system as claimed in claim 1 wherein each of said heads includes means for adjusting the sensitivity thereof as a function of the noise level detected by said head.

Claim 6

A system as claimed in claim 1 wherein said circuit means includes a system circuit connected to said plurality of heads and assuming an alarm condition in response to an output pulse from one of said heads and control means connected to said system circuit and initiating an alarm in response to said alarm condition.

Claim 7

An alarm system comprising a plurality of detection heads disposed within an area for detecting sounds occurring within said area, each having a limited range for detecting sounds occurring only within a portion of said area and each having means for generating an output pulse only in response to the detection of those sounds occurring within said area as are indicative of the occurrence of an alien disturbance, system circuit means having a normal condition and at least a first alarm condition and responsive to an output pulse from any one of said heads for assuming said first alarm condition, and control means responsive to said first alarm condition for initiating an alarm.

Claim 8

An alarm system comprising a plurality of detection heads disposed within an area for detecting sounds occurring within said area, each having a limited range for detecting sounds occurring only within a portion of said area and each having means for generating an output pulse only in response to the detection of those sounds occurring within said area as are indicative of the occurrence of an alien disturbance, system circuit means having a normal condition and at least a first alarm condition and responsive to an output pulse from any one of said heads for assuming said first alarm condition, and control means responsive to said first alarm condition for initiating an alarm.

Claim 9

A system as claimed in claim 6 wherein said first alarm condition is a short in said system circuit means.

Claim 10

A system as claimed in claim 6 wherein said circuit means has a second alarm condition, said control means being responsive to said second alarm condition for initiating an alarm.

Claim 11

A system as claimed in claim 8 wherein said second alarm condition is an open circuit in said system circuit means.

Claim 12

A system as claimed in claim 6 in which each detection head includes means for determining whether detected sounds are indicative of an alien disturbance comprising means for counting the number of sounds detected by said head, and means for generating said output pulse in response to a selected number of sounds detected within a selected period of time.

Claim 13

A system as claimed in claim 6 in which each detection head includes means for determining whether detected sounds are indicative of an alien disturbance comprising means for generating said output pulse in response to the existence of a detected sound having a duration greater than a selected period of time.

Claim 14

A system as claimed in claim 6 in which each detection head includes means for rendering said detection head insensitive to detected sounds occurring outside of said area.

Claim 15

A system as claimed in claim 6 including an inhibit head responsive to the occurrence of selected nonalien sounds occurring within said area for generating an inhibit signal, and means for connecting said inhibit head only to those of said detection heads capable of detecting said selected nonalien sounds, whereby said inhibit signal prevents said certain detection heads from generating an output pulse in response to said selected nonalien sounds.

Claim 16

An intruder alarm system comprising in combination a plurality of detEction heads for detecting sounds occurring within an area, each of said heads including an audio transducer for detecting sounds occuring only within a portion of said area and for generating electrical signals in response thereto, discriminating means for eliminating the low frequency portion of each said signal to prevent detection of sounds from outside the area, quantizing means for generating a single standard pulse in response to each of said signals, circuit means for counting said standard pulses and for generating a voltage in response to the occurrence of a selected number of said standard pulses within a selected interval of time, said counting circuit means also being responsive to said electrical signals for generating said voltage in response to an electrical signal having a duration greater than a selected period of time, and output-sensing means for generating an output pulse in response to said voltage, and control means for initiating an alarm in response to an output pulse from anyone of said heads.

Claim 17

An intruder alarm system comprising in combination a plurality of detEction heads for detecting sounds occurring within an area, each of said heads including an audio transducer for detecting sounds occuring only within a portion of said area and for generating electrical signals in response thereto, discriminating means for eliminating the low frequency portion of each said signal to prevent detection of sounds from outside the area, quantizing means for generating a single standard pulse in response to each of said signals, circuit means for counting said standard pulses and for generating a voltage in response to the occurrence of a selected number of said standard pulses within a selected interval of time, said counting circuit means also being responsive to said electrical signals for generating said voltage in response to an electrical signal having a duration greater than a selected period of time, and output-sensing means for generating an output pulse in response to said voltage, and control means for initiating an alarm in response to an output pulse from anyone of said heads.

Claim 18

A system as claimed in claim 14 including system circuit means having a normal system impedance condition defined by a terminal impedance, means for connecting each of said heads in parallel with said terminal impedance, each of said heads defining an open circuit and including means to short circuit said system circuit in response to said output pulse to define a first system alarm impedance condition, said control means including a circuit monitor for sensing the impedance condition of said system circuit and alarm initiating means connected to said circuit monitor, said circuit monitor energizing said alarm-initiating means in response to said first system alarm impedance condition.

Claim 19

A system as claimed in claim 15 wherein effective removal of said terminal means from said system circuit means increases the impedance of said system circuit means to define a second alarm impedance condition, said circuit monitor energizing said alarm-initiating means in response to said second alarm impedance condition.