| 释义 |
▪ I. ˈquieting, vbl. n.
[f. quiet v. + -ing1.]
1. The action of the vb.
a1548Hall Chron., Hen. VIII, 179 He..for quietyng of his conscience called together the best lerned of the realme. a1652J. Smith Sel. Disc. x. 511 A pacifying and quieting of all those riots and tumults. 1783F. Burney Diary 18 Jan., I felt so fagged..that I really wanted quieting and refitting. 1861Goldw. Smith Irish Hist. 105 To withhold the capital ‘grace’ concerning the quieting of titles to land.
2. Radio.
a. The automatic reduction of the gain and therefore the noise of a receiver when there is no usable signal.
1937F. E. Terman Radio Engin. (ed. 2) xiii. 561 In tuning a sensitive receiver provided with automatic volume control, the noise output between stations is high because, when no signal is being received, the A.V.C. system increases the sensitivity of the receiver to the maximum possible value. Arrangements for eliminating this interstation noise are variously known as Q circuits, quieting systems, squelch circuits, etc. 1959R. L. Shrader Electronic Communication xvii. 554 (caption) A squelch interstation quieting, or Q, circuit.
b. The reduction of the noise level in a receiver caused by the presence of an input at the frequency to which it is tuned.
1949Proc. IRE XXXVII. 1373/2 The quieting-signal-sensitivity test input is the least unmodulated signal input which, when applied to the receiver through the standard dummy antenna, reduces the receiver noise by a factor of 20 decibels. 1960IRE Trans. Vehicular Communications Dec. 32/2 Two methods of measuring sensitivity are recognized... The oldest and probably the most used is the quieting method. This procedure measures the on-frequency signal level required to reduce the noise output of a receiver by 20 db. 1974Harvey & Bohlman Stereo F.M. Radio Handbk. iii. 41 Receiver sensitivity must be quoted together with the corresponding noise figure; a typical figure for a good circuit is 2µV for 30 dB quieting.
▪ II. ˈquieting, ppl. a.
[-ing2.]
That quiets.
1659A. Hay Diary (S.H.S.) 80 There is a quieting rest under Christ's wings. 1759H. Walpole Lett. to Mann 9 Feb. (1846) III. 432 The Parliament has taken a quieting-draught. 1839I. Taylor Anc. Chr. I. 22 The quieting recollection that they themselves are members of a series. 1846Trench Mirac. xxxii. (1862) 450 The Lord spoke these quieting words to his disciples. |