Method and apparatus for detecting a hazard detector signal in the presence of interference
First Claim
1. An apparatus for detecting a pattern warning signal from a hazard detector in the presence of a second pattern warning signal from a second hazard detector, comprising:
- a transducer for converting the pattern warning signal and the second pattern warning signal to a composite electronic signal, each of the first and second pattern warning signals comprising an on-time period followed by an off-time period;
an analog-to-digital for converting the composite electronic signal into a digital signal;
a memory for storing processor-executable instructions and one or more thresholds;
a transmitter for transmitting an alarm signal; and
a processor coupled to the transducer, the memory and the transmitter for executing the processor-executable instructions that causes the apparatus to;
determine an on-time duration of the digital signal as a time that the digital signal exceeded a first voltage threshold; and
transmit an alarm signal to a receiver when the pattern warning signal has been determined to be present;
wherein the processor-executable instructions that cause the apparatus to determine the on-time duration of the digital signal comprise instructions that cause the apparatus to;
store a maximum on-time duration threshold in the memory equal to twice the on-time period, less a gap time period;
determine when the digital signal exceeds the first voltage threshold;
after determining that the digital signal has exceeded the first voltage threshold, determine when the digital signal falls below a second voltage threshold;
determine the on-time duration of the digital signal based on the elapsed time between when the digital signal exceeded the first voltage threshold and when the digital signal fell below the second voltage threshold;
compare the on-time duration of the digital signal to the minimum and maximum on-time duration thresholds; and
determine that the pattern warning signal is present when the on-time duration of the digital signal is greater than the minimum on-time duration threshold and less than the maximum on-time duration threshold.
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Abstract
The present disclosure describes methods and apparatus for detecting a pattern warning signal from a hazard detector in the presence of a second pattern warning signal from a second hazard detector. In one embodiment, hazard detector monitoring device converts a pattern warning signal and a second pattern warning signal into a composite electronic signal, each of the first and second pattern warning signals comprising an on-time period followed by an off-time period. Next, the composite electronic signal is converted into a digital signal and then an on-time duration of the digital signal is determined as a time that the digital signal exceeded a first voltage threshold. Finally, an alarm signal is transmitted to a receiver when the pattern warning signal has been determined to be present, based on the on-time duration.
3 Citations
10 Claims
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1. An apparatus for detecting a pattern warning signal from a hazard detector in the presence of a second pattern warning signal from a second hazard detector, comprising:
- a transducer for converting the pattern warning signal and the second pattern warning signal to a composite electronic signal, each of the first and second pattern warning signals comprising an on-time period followed by an off-time period;
an analog-to-digital for converting the composite electronic signal into a digital signal;
a memory for storing processor-executable instructions and one or more thresholds;
a transmitter for transmitting an alarm signal; and
a processor coupled to the transducer, the memory and the transmitter for executing the processor-executable instructions that causes the apparatus to;
determine an on-time duration of the digital signal as a time that the digital signal exceeded a first voltage threshold; and
transmit an alarm signal to a receiver when the pattern warning signal has been determined to be present;
wherein the processor-executable instructions that cause the apparatus to determine the on-time duration of the digital signal comprise instructions that cause the apparatus to;
store a maximum on-time duration threshold in the memory equal to twice the on-time period, less a gap time period;
determine when the digital signal exceeds the first voltage threshold;
after determining that the digital signal has exceeded the first voltage threshold, determine when the digital signal falls below a second voltage threshold;
determine the on-time duration of the digital signal based on the elapsed time between when the digital signal exceeded the first voltage threshold and when the digital signal fell below the second voltage threshold;
compare the on-time duration of the digital signal to the minimum and maximum on-time duration thresholds; and
determine that the pattern warning signal is present when the on-time duration of the digital signal is greater than the minimum on-time duration threshold and less than the maximum on-time duration threshold. - View Dependent Claims (2, 3, 4, 5)
- a transducer for converting the pattern warning signal and the second pattern warning signal to a composite electronic signal, each of the first and second pattern warning signals comprising an on-time period followed by an off-time period;
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6. A method for detecting a pattern warning signal from a hazard detector in the presence of a second pattern warning signal from a second hazard detector, comprising:
- converting the pattern warning signal and the second pattern warning signal into a composite electronic signal, each of the first and second pattern warning signals comprising an on-time period followed by an off-time period;
converting the composite electronic signal into a digital signal;
determining an on-time duration of the digital signal as a time that the digital signal exceeded a first voltage; and
transmitting an alarm signal to a receiver when the pattern warning signal has been determined to be present;
wherein determining the on-time duration of the digital signal comprises;
storing a minimum on-time duration threshold in the memory equal to the on-time period;
storing a maximum on-time duration threshold in the memory equal to twice the on-time period, less a gap time period;
determining when the digital signal exceeds the first voltage threshold;
after determining that the digital signal has exceeded the first voltage threshold, determining when the digital signal falls below a second voltage threshold;
determining the on-time duration of the digital signal based on the elapsed time between when the digital signal exceeded the first voltage threshold and when the digital signal fell below the second voltage threshold;
comparing the on-time duration of the digital signal to the minimum and maximum on-time duration thresholds; and
determining that the pattern warning signal is present when the on-time duration of the digital signal is greater than the minimum on-time duration threshold and less than the maximum on-time duration threshold. - View Dependent Claims (7, 8, 9, 10)
- converting the pattern warning signal and the second pattern warning signal into a composite electronic signal, each of the first and second pattern warning signals comprising an on-time period followed by an off-time period;
Specification