Abstract: A battery source of dc voltage continuously energizes digital circuitry for controlling operation of analog signal processing circuitry including a microphone preamplifier, an automatic gain control amplifier, a bandpass section and an output buffer driving audio reproducing equipment. The analog signal processing circuitry is energized on select command from the battery source through a switched on power supply. Automatic operation of the gain control amplifier may be disabled and the bandpass section by-passed in response to other select commands.

Abstract: A touch switch contacts on a unit housing are bridged by the fingers of a person's hand when holding the housing to trigger operation of a signal generating oscillator driving a transducer from which "voice" sound is generated and transmitted through a sound tube into the person's mouth for articulation of speech. The oscillator is operated at a low duty cycle for moderate battery consumption when the sound tube is extended from a retracted storage position within a recess formed in the housing.

Abstract: A hand held housing encloses a battery powered sound generator from which an audible voice simulating tone is transmitted through a tube when a push button switch is depressed also causing illumination of an indicator lamp. The tube is displaceable relative to the housing between extended and retracted positions. In the extended position, the tube may be inserted into the mouth.

Abstract: A catamaran boat is provided including a pair of laterally spaced apart longitudinally extending displacement-type hollow hulls. Generally horizontal connecting deck structure extends between the hulls and includes a large plan area transparent generally horizontal viewing panel supported therefrom in an opening provided in the deck structure. The boat has a loaded operational water line which is spaced below the transparent panel and the hulls include buoyancy varying structure operative to selectively flood the hulls to reduce the buoyancy thereof and raise the water line to a level above the panel and to subsequently pump out the hulls to increase the buoyancy thereof and lower the water line to the aforementioned operational water line.