Reduced power supervisory message transmission in a wireless alarm system
AssigneePittway Corporation
InventorKenneth L. Addy
Life of this patent
Estimating the term…
Abstract
A self testing wireless data communications system suitable for use with an alarm system, the transmitting element of the communications system is capable of transmitting at two different output power levels. If the message is a supervisory message, it is transmitted at a lower power level than an alarm message, in order to ensure that non-supervisory alarm messages are received with an adequate signal margin.
Claims29
A method for periodically self-testing a communications path in wireless alarm systems, which comprises:
- timing a supervisory period to provide a delay between transmissions of supervisory messages;
- generating a supervisory message;
- generating a transmission power control signal comprising one of at least two states upon termination of said supervisory period;
- and
- transmitting said supervisory message at a reduced power level as indicated by said state of said transmission power control signal.
An apparatus for periodically self-testing a communications path in wireless alarm systems, which comprises:
- supervisory period timing means for timing a duration of a supervisory period existing between transmissions of supervisory messages;
- means for outputting a supervisory period termination signal upon termination of said supervisory period;
- message generation means for generating said supervisory message and a transmission power control signal, said transmission power control signal comprising one of at least two states;
- and
- transmission means for transmitting said supervisory message at a predetermined reduced power level in response to a first state of said transmission power control signal.
An alarm sensor transmitter for use in a wireless alarm system, which comprises:
- a supervisory period timer which times a duration of a supervisory period existing between transmissions of supervisory messages and outputs a supervisory period termination signal upon termination of said supervisory period;
- a message generator which generates said supervisory message and a transmission power control signal in response to said supervisory period termination signal, said transmission power control signal comprising at least two states, said message generator generating an alarm status message and said transmission power control signal in response to receipt of an alarm status signal from an alarm sensor;
- a radio frequency transmitter which transmits said supervisory message at a predetermined reduced power level in response to said state of said transmission power control signal and transmits said alarm status message at a predetermined normal power level in response to said state of said transmission power control signal, said radio frequency transmitter modulating said transmission signal with said generated supervisory message and said alarm status message and outputting said modulated transmission signal;
- an oscillator which outputs a data clock signal for synchronizing said message generator and a phase detection clock signal for synchronizing said radio frequency transmitter, said data clock signal and said phase detection clock signal being substantially in phase with each other;
- and
- a phase lock loop circuit which substantially maintains correlation between a phase of said transmission signal and a phase of said phase detection clock signal.
Dependencies are inferred from the claim text.