Improvements in or relating to pressure wave transmitters and receivers incorporating magneto-strictive devices

Abstract

Abstract 411,903. Audible-signalling apparatus. MARCONI INTERNATIONAL MARINE COMMUNICATION CO., Ltd., Electra House, Victoria Embankment, and HINTON, N. P., 57, Broughton Avenue, Finchley, both in London. Dec. 15, 1932, No. 35620. [Class 118 (ii).] A magnetostrictive pressure wave transmitter and receiver is provided with a tapped winding so that a different and higher value of winding inductance is utilized for reception than for transmission. A discharge tube is connected across the grid and cathode of the receiving valve to prevent paralysis of the receiver during transmission. As shown in the Figure the winding of the magnetostrictive body MS is tapped at T3 and a polarizing battery B is connected through a high frequency choke HFC to this point. When the transmitting spark coil, (not shown) but connected to t1, t2 and shunted by main spark gap G is energized, the auxiliary spark gap SG breaks down and oscillating energy is applied between T3 and T2. The oscillating circuit is tuned by variometer V to the natural frequency of vibration of the magnetostrictive body. The voltage across T2, T3 is stepped up across the whole coil by auto-transformer action but the neon tube N breaks down to prevent excessive voltage passing to the receiving valve and paralyzing the receiver. During reception neither the spark gap SG nor the neon tube N breaks down so that the transmitting portion of the apparatus is isolated and the whole voltage generated in the winding W passes to the receiving valve. Specifications 402,123 and 411,879 are referred to.

Inventors

No inventors recorded.

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