| 释义 |
diˈscriminator
[a. L. discrīminātor (Tertull.), agent-n. from discrīmināre to discriminate.]
1. One who or that which discriminates.
1828Colebrooke in Trans. R. Asiat. Soc. (1830) II. 183 He [the judge] discriminates, and is, consequently, the discriminator (viváca). 1961Lancet 12 Aug. 360/1 The high number of poor discriminators is an indication that most of them can be omitted in future and other questions substituted. 1963Amer. Speech XXXVIII. 72 Plosives, fricatives, and affricatives are best discriminators between speakers with adequate and inadequate velopharyngeal closure.
2. Electr.
a. (See quot.)
1931S. R. Roget Dict. Electr. Terms (ed. 2) 89/2 Discriminator, an instrument used with an earlier system of charging of an electric supply which automatically switches over to a different meter when a predetermined maximum demand has been exceeded.
b. Any circuit the output of which depends on how some property of the input departs from a fixed level or value; esp. one that converts a frequency-modulated signal to an amplitude-modulated one by modulating the output amplitude according to the deviation of the input frequency from a fixed (carrier) frequency.
1935Proc. Inst. Radio Engineers XXIII. 1126 An automatic frequency control system will consist of two distinct units; a frequency discriminator or frequency sensitive detector that generates a bias varying with changes of the intermediate-frequency signal carrier frequency, and a control unit that is acted upon by this bias. 1947Nature 4 Jan 16/1 In order to render a frequency-modulated signal audible, the receiver uses a device known as a ‘discriminator’, which in effect converts it into an amplitude-modulated signal, which may then be detected by any of the usual methods. 1962Simpson & Richards Junction Transistors xviii. 462 The most common type of frequency-modulation detector, the discriminator, was developed originally for vacuum-tube receivers. 1962F. J. M. Farley Elem. Pulse Circuits (ed. 2) i. 19 This circuit is an example of a discriminator, that is, a circuit which transmits only the upper portion of a pulse. In common with other discriminator circuits..it may be used..to select signals of amplitude greater than a predetermined threshold value. |