Abstract: A pulse plating system wherein the duty cycle is controlled by skipping pulses in producing the output signal. The circuitry for controlling the skipping of the pulses can either be analog or digital type circuitry.

Abstract: Delivery tubes used with air caloric stimulation systems, when measuring vestibular responses. The delivery tubes fit into the patient's ears at the nozzle end thereof. Silastic tubing is provided narrower at the nozzle end for forming a higher velocity narrower stream of air directed at the tympanic membrane to produce more effective and consistent heat exchange with the labyrinth. A shield is provided to prevent the tubing from impinging on the tympanic membrane and to retain the apparatus in place. A handle is also provided to aid in the insertion of the delivery tube into the air canal, and to aid in attaching the delivery nozzle of the delivery head regularly used with the air caloric stimulation system.

Abstract: A standby power supply system utilized for continuously supplying alternating current power at a regulated value to a load independent of the line power amplitude of continuity. The standby power supply includes an inverter utilizing a direct current source. Direct current feedback circuitry is provided for improving the AC - DC synchronization, minimizing the drain on the source and for holding the direct current relatively constant thereby reducing the requirements of the direct current source.

Abstract: A switching adapter that provides a rapid and convenient apparatus for selective recording of vertical eye movements with a single channel recorder in electronystagmograph apparatus. A number of single channel recorders are used in the field to observe the horizontal eye movements elicited by thermally induced vestibular unbalance. In certain types of pathological unbalances, vertical eye movement is also present, therefore, it is highly desirable to be able to also record the vertical eye movement. The switching adapter conveniently converts single channel recorders that are normally used for recording horizontal eye movement for recording vertical nystagmus.

Abstract: The air caloric stimulation system provides an adjustable air system with accurate and automatic control of the delivery and temperature of air. A thermal electric device utilizing the Peltier effect generates or absorbs heat depending on the difference between the temperature of the air at the outlet and the "set" or desired temperature of the air at the outlet. Further, the Peltier units are aided in controlling the temperature of the air using a radiator system in conjunction with a liquid circulating system. The current to the Peltier units are controlled using unique proportional phase controlled signals. Safety circuitry prevents the air or liquid from overheating.