Wheelock, Inc.

Edward V Applegate

Joseph Kosich

John William Curran

Richard H Fetterly

Brian E Bizjak

Anthony W Russo, Ii

The present invention is an apparatus and a concomitant method for boosting the audio signal generated by at least one notification appliance in a supervised emergency voice evacuation system.

Method and apparatus for boosting an audible signal in a notification system

A strobe alarm system which includes multiple normally self-timed strobe circuits connected in a common loop to a fire alarm control panel, and a sync control circuit, which may be incorporated in the fire alarm control panel, for causing the strobes to flash in synchronism at a predetermined rate which will insure that a person viewing the multiple strobes would not see flash rates higher than the predetermined synchronized rate, which is preferably less than five flashes per second. The sync control circuit does not interfere with the supervision functions of the alarm system, and when an alarm condition is present it supplies power to the strobe circuits which it then interrupts once every flash cycle to cause a sync trigger circuit in each strobe to fire its flashtube, and to reset the internal timer of each strobe to ready it for arrival of the next sync signal. Each strobe circuit in the loop includes a resettable timer for recycling its own flash unit in a non-synchronous fail-safe mode in case the sync signal should fail to appear within a finite period following the last previous flash. That is, normally the strobes are all fired at the same time in response to sync signals applied to their sync trigger circuits, but in the event the sync signal is lacking the strobes will continue to flash, each at a rate determined by its internal timer.

Synchronization circuit for visual/audio alarms

A flashtube circuit includes a switch which in a first position regulates the storage over time of energy in a first energy storage device and in a second position allows the transfer of energy from the first energy storage device to a second energy storage device. A microcontroller receives the input voltage and then samples and digitizes it for input into a lookup table. The microcontroller repeatedly cycles the switch between flashes by controlling the time the switch is in its first position. The lookup table output provides the signal for determining the time the switch remains in its first position. The time interval from the last flash controls the time the switch is in its second position. The cycling of the switch is controlled accordingly such that the second energy storage device acquires the predetermined amount of energy for the flash just as the triggering circuit is initiated by the microcontroller. Moreover, the microcontroller controls the switch in a way such that the time the switch is in its first position is maximized and the time the switch is in its second position is generally decreased relative to the time since the last flash. This helps to minimize the peak current drawn by the first energy storage device. In addition, the strobe light circuit is capable of determining if the input voltage is D.C. or is full wave rectified and controls the switch accordingly.

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Temecula, CA, United States of America

Edward V Applegate