. Annual report of the Board of Regents of the Smithsonian Institution . Fig. 2.—Wireless Telephone Receiver, with Thin CopperDiaphragm Repelled by Resistance Coil of 16 Fig. 3.—Transformer Used in Transmitting Circuit. WIBELESS TELEPHONY—FESSENDEN. 177 Duplex and multiplex methods.—A considerable number of thesehave been worked out, mostly operating either by balance methods or commutators.^ It is impossible to discuss all the various improve-ments, such, for example, as the method of indicating the busj^ andfree state of a station, the methods of sending and receiving in onedirection,
. Annual report of the Board of Regents of the Smithsonian Institution . Fig. 2.—Wireless Telephone Receiver, with Thin CopperDiaphragm Repelled by Resistance Coil of 16 Fig. 3.—Transformer Used in Transmitting Circuit. WIBELESS TELEPHONY—FESSENDEN. 177 Duplex and multiplex methods.—A considerable number of thesehave been worked out, mostly operating either by balance methods or commutators.^ It is impossible to discuss all the various improve-ments, such, for example, as the method of indicating the busj^ andfree state of a station, the methods of sending and receiving in onedirection, the various types of aerials used for receiving the othercomponents of the electromagnetic waves besides the electrostaticcomponent, etc, Plate 3, figure 1, shows the harmonic interrupter for determiningthe variation of intensity with change of note. Plate 3, figure 2, shows a type of receiver described in UnitedStates patent No. 706747, in which the telephone diaphragm is formedof thin copper and repelled by a fixed coil having a resistance ofabout IG ohms. The principle of this receiver was discovered byProf. Elihu Thomson. It has been used for wireless telepho
Size: 2063px × 1211px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsmithsonianinstitutio, bookcentury1800, bookdecade1840
