Noise generator circuit for a security system

• US 4,064,507 A
• Filed: 05/29/1975
• Issued: 12/20/1977
• Est. Priority Date: 05/29/1975
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Schmitz, Lawrence S.
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/582,552
• Time in Patent Office: 936 Days
• Field of Search: 340/420, 340/416, 340/410, 340/414, 340/226, 340/213 R, 340/253 C, 340/384 E, 340/409, 340/312, 340/279, 340/276, 307/271
• US Class Current: 340/384.72
• CPC Class Codes: G08B 19/00 Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow
• CPC Class Codes: G08B 29/04 Monitoring of the detection circuits
• CPC Class Codes: G08B 29/06 Monitoring of the line circuits, e.g. signalling of line faults
• CPC Class Codes: G08B 29/08 Signalling of tampering with the line circuit
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission

Abstract

A solid state noise generator circuit responds to digital signals indicative of alarm conditions, by initiating frequency modulated digital audio output waveforms distinctly identifying the monitored condition to provide audible recognition of each alarm condition. Each distinct alarm condition results in the application of a different combination of outputs of one multistage counter as preset inputs to a second multistage counter to uniquely frequency modulate the digital square wave input driving the second multistage counter to produce the distinctive frequency modulated digital audio output waveform.

Claims

1. In a solid state security system having input circuits adapted to receive input signals from security sensors monitoring two or more alarm conditions and generating a separate digital output signal in response to the occurrence of each alarm condition, the combination of, a digital noise generator circuit means responsive to said digital output signal by initiating a digitally modulated, frequency modulated digital audio waveform uniquely indicative of the alarm condition represented by said digital output signal, each of said digitally modulated, frequency modulated digital audio waveforms conisting of a periodic repetition of a predetermined pattern of frequency versus time waveform segments, and audio means for audibly manifesting said frequency modulated digital audio waveform.

2. In a solid state security system having input circuits adapted to receive input signals from security sensors monitoring two or more alarm conditions, and generating a separate digital output signal in response to the occurrence of each alarm condition, the combination of, a digital noise generator circuit means responsive to said digital output signal by initiating a frequency modulated digital audio waveform uniquely indicative of the alarm condition represented by said digital output signal, and audio means for audibly manifesting said frequency modulated digital audio waveform,

wherein said noise generator circuit means includes a first multistage counter means and a second multistage counter means, said first multistage counter means being set to a predetermined count level by inputs supplied to a plurality of preset counter inputs and being driven by a digial input, logic means operatively connecting a plurality of the outputs of said second multistage counter means in a feedback relationship to said preset inputs of said first multistage counter means, each of said digital output signals indicative of a different alarm condition controlling said logic means to apply a predetermined combination of said outputs from said second multistage counter means as inputs to said preset inputs of said first multistage counter means, said inputs to said preset input of said first multistage counter means functioning to produce said frequency modulated digital audio output waveform as an output from said second multistage counter means, each of said digital output signals causing a distinctive frequency modulated digital audio output waveform to be produced which is indicative of the corresponding alarm condition.

3. In a solid state security system as claimed in claim 2 wherein the number of stages of said second multistage counter means is at least equal to the number of stages of said first multistage counter means.

4. In a solid state security system as claimed in claim 2 wherein at least three alarm conditions are monitored, fire, intrusion and emergency, and separate digital output signals are developed in response to the occurrence of one or more of these alarm conditions, an alarm priority circuit means operatively coupling said input circuit means and said noise generator circuit means to evaluate simultaneously generated digital output signals in accordance with a predetermined alarm priority and supplying digital control signals to said logic means in accordance with said alarm priority such that the input signals supplied to the preset input of said first multistage counter means from the output of said second multistage counter means will produce a frequency modulated digital audio output waveform indicative of the first priority alarm condition.

5. In a solid state security system as claimed in claim 2 wherein each of said frequency modulated digital audio output waveforms consist of one or more frequencies all of which are whole number multiples of the fundamental frequency of said digital input driving said first multistage counter means.

6. In a solid state security system having input circuits adapted to receive input signals from security sensors monitoring two or more alarm conditions, and generating a separate digital output signal in response to the occurrence of each alarm condition, the combination of, a digital noise generator circuit means responsive to said digital output signal by initiating a digitally modulated, frequency modulated digital audio waveform uniquely indicative of the alarm condition represented by said digital output signal, wherein a distinctive digitally modulated, frequency modulated digital audio waveform is generated to identify a fire alarm condition, the frequency modulated digital audio waveform indicative of a fire alarm condition consisting of a repetition of a pattern of frequency versus time waveform segments a, b, a, b, b, a, b, a where:

a is defined as approximately 868 Hz for 18 milliseconds, and b is defined as approximately 1216 Hz for 14 milliseconds, and audio means for audibly manifesting said frequency modulated digital audio waveforms.

7. In a solid state security system having input circuits adapted to receive input signals from security sensors monitoring two or more alarm conditions, and generating a separate digital output signal in response to the occurrence of each alarm condition, the combination of, a digital noise generator circuit means responsive to said digital output signal by initiating a digitally modulated frequency modulated digital alarm waveform uniquely indicative of the alarm condition represented by said digital output signal, wherein a distinctive digitally modulated, frequency modulated digital audio waveform is generated to identify an intrusion alarm condition, said waveform consisting of a repetition of a pattern of frequency versus time waveform segments a, b, a, b, c, d, c, d, where:

a is defined as a sweep from approximately 1034 Hz to 772 Hz in about 73 milliseconds;

b is defined as a sweep from approximately 1520 Hz to 1034 Hz in about 52 milliseconds;

c is defined as a sweep from approximately 1034 Hz to 1520 Hz in about 49 milliseconds; and

d is defined as a sweep from approximately 772 Hz to 1034 Hz in about 73 milliseconds; and

audio means for audibly manifesting said frequency modulated digital audio waveforms.

8. In a solid state security system having input circuits adapted to receive input signals from security sensors monitoring two or more alarm conditions, and generating an alarm output signal in response to the occurrence of each alarm condition, the combination of, a digital noise generator circuit means and an excitation means having a fundamental frequency for driving said digital noise generator circuit means, said digital noise generator circuit means responding to an alarm output signal by initiating a frequency modulated digital audio waveform uniquely indicative of the alarm condition represented by said output signal wherein each of the frequency modulated digital output signals initiated in response to different alarm condition consist of one or more frequencies, all of which are whole number multiples of the fundamental frequency of said excitation means.