The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 72
undernormal conditions.If the contact oforms part of acircuit which in-cludes a batteryand the receiver,Fig. 31, and themembrane be setin vibration by amusical sound, thecircuit will be interrupted at every vibration. Each inter-ruption produces a sound in the receiver, and a musical soundsimilar… … Fig. 31 keys for signalling pur-poses. By such means the pitchof any sound may be re-produced at a distance;but this was not enoughfor the transmission ofspeech. Pitch is only oneof the characteristics ofsound, for besides it, soundhas quality or timbre, anddegrees of loudness ox in-tensity, which…
Telephone
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