| 释义 |
psophometer Electr.|sɒˈfɒmɪtə(r)|
[f. Gr. ψόϕος noise + -meter.]
An instrument for giving a reading approximately proportional to the subjective aural effect of the noise in a communication circuit.
1938Jrnl. Inst. Electr. Engineers LXXXIII. 261/1 The circuit noise meter (or psophometer) is an instrument which has been designed for measuring the disturbing effect of power induction on telephone communication. 1953P.O. Electr. Engineers' Jrnl. XLVI. 112/1 The use of the psophometer has extended in recent years from the function of power circuit noise interference measurement to the measurement of overall noise on [telephone] transmission lines and equipment. 1975J. E. Flood Telecommunication Networks ii. 48 Noise is usually measured by a meter having a frequency-weighting network which has been standardised by the CCITT. Such instruments are called psophometers.
Hence psophoˈmetric a. (see quot. 1943); psophoˈmetrically adv.
1943Gloss. Terms Telecommunications (B.S.I.) 15 Psophometric voltage, the voltage at 800 c/s between two points in a telephone system which, if it replaced the disturbing voltage, would produce the same degree of interference with a telephone conversation as the disturbing voltage. 1951Electronic Engin. XXIII. 35 Typical figures permitted are 2 mV of weighted (psophometric) ripple. 1975J. E. Flood Telecommunication Networks ii. 48 For white noise in the band 0–4 kHz, the effect of psophometric weighting is to reduce the noise level by 3·6 dB. Ibid., Noise power is..measured in units of pWp (picowatts psophometrically weighted) or dBmp (decibels relative to 1 mW psophometrically weighted). |