Alarm Notification Appliance Self-Testing with Ambient Noise Discrimination
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Solution Overview
Problem
Existing self-test technologies for notification appliances in alarm systems fail to discriminate between the output generated by the appliances' notification features and ambient sound or light from other sources, leading to false positive results during self-testing.
Innovation Solution
A method that includes an ambient noise detection period where sensors measure and compare ambient light levels against a threshold, preventing false positives by ensuring that ambient noise does not interfere with the self-test results, allowing the notification appliances to accurately assess their functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-test technologies are used to automatically evaluate notification appliance functionality, then the burden on inspectors is reduced and testing efficiency is improved, but false positive results occur when sensors cannot discriminate between appliance output and ambient noise
Solution Approach 1:
The system performs preliminary ambient noise measurement before conducting the actual self-test. This preliminary action establishes a baseline of ambient conditions, allowing the system to later distinguish between ambient noise and actual appliance output during the test, thereby preventing false positives while maintaining automated testing efficiency
Solution Approach 2:
The system continuously monitors ambient noise levels and uses this feedback to adjust or invalidate test results. By comparing test measurements against pre-established ambient noise baselines, the system can identify and reject false positive results, improving self-test accuracy while maintaining automated operation
2Measurement precision
If sensors continuously monitor output during self-test, then measurement precision is improved, but ambient noise from other sources causes false positive results
Solution Approach 1:
The system extracts and separately measures ambient noise levels before conducting the actual self-test. By isolating and characterizing the ambient noise component, the system can then subtract or filter this interference from the total measured signal during testing, thereby maintaining measurement precision while eliminating false positives caused by ambient noise
Solution Approach 2:
The system introduces an ambient noise baseline as an intermediary reference. This baseline acts as a mediator that allows the system to distinguish between ambient noise and actual appliance output by comparing test measurements against the established baseline, thereby improving measurement accuracy while compensating for ambient interference
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate self-testing by distinguishing between actual output from the notification appliances and ambient noise, reducing the likelihood of false positives and ensuring reliable functional assessments without the need for physical inspections.
Implementation Method 1
a notification appliance that is equipped with self-test capability may include one or more sensors, such as a microphone, sound detector, camera, photo eye, light detector, etc.
Implementation Method 2
sensors measure and compare ambient light levels against a threshold
Data Source
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AI summary
Method for self-testing notification appliances in an alarm system, including the steps of measuring ambient noise at a notification appliance, comparing the measured ambient noise to a threshold ambient noise level, and performing a self-test of the notification appliance if the measured ambient noise does not exceed the threshold ambient noise level. Method may further include the step of recording a fail result for the notification appliance if the measured ambient noise exceeds the threshold ambient noise level. Performing the self-test of the notification appliance may include the steps of activating a notification feature of the notification appliance, measuring output of the notification feature, comparing the measured output to a predefined value, recording a pass result for the notification appliance if the measured output exceeds the predefined value, and recording a fail result for the notification appliance if the measured output does not exceed the predefined value.