LOUDNESS MEASURING DEVICE

摘要

PURPOSE:To take an objective measurement of loudness by inputting a pseudo voice signal to a telephone set from a pseudo mouth or current supply circuit, and performing digital arithmetic based upon the spectrum of the pseudo voice inputted to the telephone set and the spectrum of an output signal. CONSTITUTION:The handset 1 of the telephone set is equipped with a transmitter 2 and a receiver 3, and a telephone set circuit 4 is connected to a pseudo subscriber line and the current supply circuit 5. A voice is applied to the transmitter 2 from the pseudo mouth 7 and a voice from the receiver 3 is acquired by a reference microphone 9 incorporated in a pseudo ear 8. A signal to the pseudo mouth 7 is supplied through a transmitting amplifier 11 and a receiving attenuator 12 and the output of the pseudo ear 8 is supplied to a receiving amplifier 13 and a receiving attenuator 14. Output/input changeover switches 17 and 18 are connected to DA and AD converters 20 and 23 through filters 19 and 22 and operated under the control of a microcomputer 27. An analyzing filter 24 and a square-law arithmetic circuit 25 makes a spectrum analysis of the pseudo voice to estimate the loudness.