Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of BE407140ApublicationCriticalpatent/BE407140A/xx
H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
H04B1/06—Receivers
H04B1/16—Circuits
H04B1/20—Circuits for coupling gramophone pick-up, recorder output, or microphone to receiver