Monitoring system for a direct-wire alarm system
First Claim
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1. A direct-wire alarm monitoring system for high-speed sequential monitoring of a plurality of DC current loops comprising:
- (a) an analog-to-digital converter means for each loop to convert the current level to a digital value;
(b) a digital notch filter operably connected to the analog-to-digital converter to eliminate periodic noise of a pre-determined period from each loop sequentially;
(c) a digital comparator operably connected to the output of the notch filter to detect changes in current level;
(d) a digital pulse filter operably connected to the output of the digital comparator to eliminate pulse noise if a change in current level is detected by the digital comparator; and
(e) means for sequentially sampling the output of the analog-to-digital converter means for each loop and applying that sample sequentially to the digital notch filter.
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Abstract
A direct-wire alarm system for scanning and monitoring a plurality of security alarm systems located in various user'"'"'s facilities. The device monitors each line sequentially and converts current levels present on each line to a digital value. A digital filter is utilized to eliminate periodic line noise while a second digital filter is utilized to eliminate pulse noise. The system further comprises a line ringing system for notifying the user of a line condition and an adjustable comparator for obtaining high resolution of line current values.
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Citations
14 Claims
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1. A direct-wire alarm monitoring system for high-speed sequential monitoring of a plurality of DC current loops comprising:
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(a) an analog-to-digital converter means for each loop to convert the current level to a digital value; (b) a digital notch filter operably connected to the analog-to-digital converter to eliminate periodic noise of a pre-determined period from each loop sequentially; (c) a digital comparator operably connected to the output of the notch filter to detect changes in current level; (d) a digital pulse filter operably connected to the output of the digital comparator to eliminate pulse noise if a change in current level is detected by the digital comparator; and (e) means for sequentially sampling the output of the analog-to-digital converter means for each loop and applying that sample sequentially to the digital notch filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification