Improvements in or relating to optical systems for photographic recording of the waveform of electric currents such as those influenced by sound waves

摘要

366,254. Oscillographs. CASTELLAIN, A. P., 8, Clydesdale Mansions, Bayswater, London. Jan. 14, 1931, No. 1307. [Class 37.] In recording electric currents such as those representing sound by apparatus utilizing a reflecting oscillograph, interference by stray light is reduced by roughening the edges of the oscillograph mirror or reflector and covering these with a coating of non-reflecting material such as acetate black which may be extended over part of the reflecting face in the form of a frame. Specification 365,559, [Group XXXVIII], is referred to.