Sound generating system for a sound masking package

Sound generator

Sound producing device

Sound simulator for model steam engine

Sound-effects generating device for activity toys or vehicles

Speaker activation control by microcomputer

Speaker driver

Substitute warning device for automobile seat belt reminder alar

Switch-off device for electrically operated clock alarm and cont

Switching amplifier and electronic siren employing the same

System for controlling an electronic warning device

System for selectively operable dual simultaneous siren broadcas

System to avoid the collision of a vehicle with animals

Termite acoustic detection

Tone generator for use with hearing aids

Tone ringer for telephone sets and other telecommunications appa

Tone signal generating system for use in communication apparatus

Tone-pip-signal generator

Two-tone audible warning circuits

Ultra-sonic dog-expelling device