Federal Signal Corporation

Lonnie E Moravetz

Scott M Cassidy

Mark J Dietel

Robert Steiert

David L Corey

An example speaker for providing alerts includes: a housing and a cover forming an integrated unit; a microphone configured to sense an ambient noise level; and a processor configured to adjust a volume of the speaker based upon the ambient noise level. A hinge can be positioned between the housing and the cover to allow the cover to be pivoted relative to the housing from a close position to an open position.

Speaker with automatic volume control

A tone generation system includes a square wave signal generator configured to generate a first series of square wave signals to replicate a fundamental frequency of a desired mechanical tone, and a second series of square waves signals to replicate a second harmonic of the desired mechanical tone. An amplifier is configured to receive the first and second series of square waves, and a speaker is connected to receive an output signal from the amplifier.

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Lincoln, NE, United States of America

Lonnie E Moravetz