Excessive noise level alerting device
First Claim
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1. A sound-detection and alerting system, comprising:
- a device for capturing acoustic energy and producing a representative electric signal;
a filter for limiting a plurality of frequencies of the electric signal to predetermined frequency ranges;
a comparator for comparing the representative electric signal to an established threshold signal and producing a corresponding comparator output signal;
a smoothing rectifier for reducing oscillations in the comparator output signal and producing a smoothed output signal; and
a timer for determining whether the smoothed output signal is within a pre-determined voltage range for at least a pre-determined period of time and producing a notification-device activation signal.
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Abstract
A sound-detection and alerting system (SDAS) is designed for use in hospitals, offices, or other environments where excessive noise levels are of concern. The SDAS depends on several variables to trigger an alarm so that false alarms are kept to a minimum. A microphone circuit captures acoustic energy which is limited to specific frequencies by a bandpass filter. A comparator integrates the various frequencies and compares them to a threshold signal. A delay timer ensures that signals exceeding the threshold signal are persistent for a pre-determined period of time.
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Citations
18 Claims
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1. A sound-detection and alerting system, comprising:
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a device for capturing acoustic energy and producing a representative electric signal;
a filter for limiting a plurality of frequencies of the electric signal to predetermined frequency ranges;
a comparator for comparing the representative electric signal to an established threshold signal and producing a corresponding comparator output signal;
a smoothing rectifier for reducing oscillations in the comparator output signal and producing a smoothed output signal; and
a timer for determining whether the smoothed output signal is within a pre-determined voltage range for at least a pre-determined period of time and producing a notification-device activation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A sound-detection and alerting system, comprising:
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a device for capturing acoustic energy and producing a representative electric signal;
a filter for limiting a plurality of frequencies of the electric signal to predetermined frequency ranges;
an integrator for integrating said plurality of frequencies to produce a representative sound level signal;
a comparator for comparing the representative sound level signal to an established threshold signal and producing a corresponding comparator output signal; and
a smoothing rectifier for reducing oscillations in the comparator output signal and producing a smoothed output signal;
a timer for determining whether the smoothed output signal is within a pre-determined voltage range for at least a pre-determined period of time and producing a notification-device activation signal.
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14. A method of activating a notification device, comprising the steps of:
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capturing acoustic energy and producing a representative electric signal;
subsequently limiting a plurality of frequencies of the electric signal to predetermined frequency ranges;
subsequently comparing the electric signal to an established threshold signal and producing a corresponding comparator output signal;
reducing oscillations in the comparator output signal and producing a smoothed output signal; and
determining whether the smoothed output signal is within a pre-determined voltage range for at least a pre-determined period of time and producing a notification-device activation signal. - View Dependent Claims (15, 16, 17, 18)
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Specification