Science Accessories Corp.

Stanley Schorum

Robert Butler

The disclosure is directed to a circuit for producing electrical discharges in response to trigger signals, and a form of the disclosure is directed to an apparatus, which includes such a circuit, for determining the transit time of acoustic energy travel between a transmitter location and a receiver location. In a disclosed embodiment, means are provided for generating acoustic energy at the transmitter location in response to trigger signals, including: a transformer having primary and secondary windings; a transducer coupled to the secondary winding; a silicon controlled rectifier coupled in series arrangement with the primary winding; a capacitor coupled to said series arrangement of primary winding and silicon controlled rectifier; a source of electrical potential coupled to the capacitor; means for coupling the trigger signals to the gate electrode of the silicon controlled rectifier; and means responsive to said trigger signals for temporarily diverting current from said source away from the capacitor, primary winding, and silicon controlled rectifier. An acoustic receiver is provided at the receiver location. A timer is initialized when the acoustic energy is generated. The receipt of acoustic energy is detected at the receiver location and a terminating signal is generated in response thereto, the timer being terminated in response to the terminating signal. The time measured by the timer is indicative of the transit time of acoustic energy travel between said transmitter and receiver locations. For two or three dimensional digitizers, the position of a moveable element can be determined from transit times between one or more transmitters and one or more receivers.

SCR control for high current discharge circuit

The disclosure is directed to a method and apparatus for more accurately determining the transit time of acoustic energy travel between a transmitter location and a receiver location. An electrode pair spark gap is provided at the transmitter location, and an acoustic receiver is provided at the receiver location. The spark-gap is energized to produce a spark by coupling an electrical potential across the electrode pair. The generation of a spark at the spark gap is sensed, and an initializing signal is generated in response thereto. A timer is initialized in response to the initializing signal. The receipt of acoustic energy from the spark is detected at the receiver location and a terminating signal is generated in response thereto. The timer is terminated in response to the terminating signal, and the time measured by the timer is indicative of the transit time of acoustic energy travel between the transmitter and receiver locations. In a preferred embodiment, the means for sensing the generation of a spark at the spark-gap is operative to sense a current coupled to the electrode pair.

Apparatus and method for determining travel time of acoustic energy

The disclosure is directed to an apparatus and method for determining the travel time of acoustic energy over an unknown travel distance between an acoustic transmitter and an acoustic receiver. This information can be used, for example, to determine the position of a moveable element in a data space. A timer is initiated at the time of acoustic transmission from the transmitter. A control signal generator is provided, and is initiated at the time of acoustic transmission from the transmitter, the control signal being a function of the time which elapses after the time of acoustic transmission. The gain of the signal received at the receiver is controlled in accordance with the control signal. The timer is terminated when the gain-controlled received signal exceeds a predetermined threshold. In a preferred embodiment, the terminating means includes a comparator for comparing the gain-controlled received signal to the predetermined threshold. The magnitude of the control signal varies as

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Madison, CT, United States of America

Stanley Schorum