GB527264A - Improvements in or relating to amplifiers for "echo" sounding apparatus - Google Patents

Abstract

527,264. Echo-sounding apparatus. GLAZER, D. S. T., and MARIE, R. April 5, 1939, No. 10643. Convention date, April 5, 1938. [Class 118 (ii)] [Also in Groups XL and XXXIX] An amplifier for aerial or submarine echo sounding apparatus comprises a band-pass filter and a two-stage tuned amplifier coupled by a tuned transformer to a gas discharge device which operates the chronographic apparatus. The Figure shows amplifying valves 31, 32 with a filter 36 and tuned transformer input 37 and a tuned coupling 41, 42. The output is applied through tuned transformer 47 to a gas discharge device 49, limiting being effected by diodes 86. The tuned circuits are shielded by thick ferromagnetic screens 50 ... 52. Operation by interference is reduced by accurate adjustment of the supply voltages by barretter 53 and gas discharge regulator tube 56. Cam 64 applies a prohibitive bias to amplifier 31 during operation of the emitter 67 and progressively increases the sensitivity of the amplifier the longer the period before the echo is received. Cam 74 ensures that the non-receipt of the echo for a pre-determined time indicates that the vessel is in a safety zone. The time constants of relays 60, 77 are adjusted by condensers 78, 79 and by resistance 80 to produce signals of adequate duration. The Specification as open to inspection under Sect. 91 comprises also a microphone construction in which the unit is protected from acoustic and mechanical vibration by insulating material 6, 7, 8 and from electromagnetic interference by a screen 12. Fig. 1 (Cancelled). The horn is shaped to be selective to the frequency received. This subject-matter does not appear in the Specification as accepted.