| 释义 |
selectivity|ˌsɛlɛkˈtɪvɪtɪ|
[f. selective a. + -ity.]
1. Radio. The ability of a receiver to tune separately to signals of adjacent frequencies, measured by the frequency difference between the half-power points of the pass-band of the receiver.
1903Electr. World & Engin. 1 Aug. 173/2 The system of selectivity devised by Sir Oliver [Lodge] was the outcome of a series of classical experiments based upon his syntonic Leyden jars in which one jar is caused to discharge through a circuit by the sparks of another jar, provided the two circuits are of equal electrical dimensions. 1930Manch. Guardian 20 Sept. 15/7 It is no exaggeration to say that..four-valve sets are more than equal in power and selectivity to a six or seven-valve set of the old type. 1943C. L. Boltz Basic Radio viii. 131 The sharper is the resonance curve the better it will select, for supplies at frequencies quite near the resonant one will have very much less effect. The sharpness of the curve is therefore a measure of the selectivity. 1976Which? Sept. 203/2 If you want to receive particularly weak signals, you need a set which has good selectivity.
2. gen. The quality of being selective.
1948E. G. Boring et al. Found. Psychol. x. 218/1 This selectivity of perception amounts to giving one sense impression a clear track. 1951Ruesch & Bateson Communication iii. 84 An alternate solution of the psychiatrist is to abstract and condense his observations before writing them down; selectivity, therefore, becomes an unavoidable issue. 1969Computers & Humanities III. 278 The main program was the Formatting Program in which the two files were used as input to produce six indexes, four of which were selective. A ‘selectivity module’ had been introduced to make the selections possible. a1974R. Crossman Diaries (1976) II. 471 We were able to discuss one of the minor sensations of the recess—Ray Gunter's speech in August, in which he said we must be realistic and brave and face up to the need for selectivity and the means test. 1978G. Underwood Strategies of Information Processing vii. 235 To information processing theory..attention and selectivity are central features. |