| 释义 |
ˈfeedback, feed-back, n.
[f. feed v. + back adv.]
a. Electr. The return of a fraction of the output signal from one stage of a circuit, amplifier, etc., to the input of the same or a preceding stage; positive feedback, negative feedback, tending to increase, decrease, the amplification, etc.; also, a signal so returned.
1920Wireless Age VIII. 27/1 An inductive feed-back in relation to the secondary system generates local oscillations. 1923Daily Mail 19 May 4 The feed-back circuit. 1946Nature 9 Nov. 670/1 The signal to noise ratio was increased by the application of positive feed⁓back to the tuned circuit. 1949Electronic Engin. XXI. 358/3 To obtain the maximum stabilising effect it is desirable to take the feedback from the output and apply it at the input in the correct phase for degeneration. 1962M. G. Say Newnes Conc. Encycl. Electr. Engin. 289/1 The feedback principle is applied in electronic amplifiers, process controls and accurate servo⁓mechanisms.
b. transf. The modification, adjustment, or control of a process or system (as a social situation or a biological mechanism) by a result or effect of the process, esp. by a difference between a desired and an actual result; information about the result of a process, experiment, etc.; a response.
1943Philos. Sci. X. 19 Purposeful active behavior may be subdivided into two classes: ‘feed-back’ (or ‘teleological’) and ‘non-feed-back’ (or ‘non-teleological’). 1945Jrnl. Franklin Inst. CCXL. 265 The shaft motion produced as the result of a sequence of operations is connected back into the sequence, a process called ‘feed⁓back’. 1955Times 31 Aug. 9/4 Only by constant ‘feed⁓back’ from the receptor can one ascertain how far a message has been understood rightly. 1959J. L. M. Trim in Quirk & Smith Teaching of English iii. 84 In..a lecture..the live speaker has a reaction, a ‘feed-back’ from the listeners, and..he can adjust his speech accordingly. 1962Listener 30 Aug. 303/2 The feed-back from technology..has resulted in the production of more powerful and discriminating instruments. 1968Times 6 Dec. 19/2 The production of both hormones seems to be regulated on a feedback mechanism by the level of calcium in the blood. 1970Sci. Amer. Mar. 68/3 The brain has to receive feedback from the muscles and joints to correct the program of impulses directed to the motor apparatus. 1971Frendz 5 Aug. 20/1 We began to get a fairly good feedback from most people who know about it and it looked as though the concerts would be good scenes.
▸ The effect whereby sound from a loudspeaker reaches a microphone feeding the speaker, thereby distorting the sound, and typically generating a screeching or humming noise; this distorted sound, esp. (in Music) created as a deliberate effect, usually through the amplifier of an electric guitar.
1936Science 26 June 628/1 A button conveniently located on the side is used to turn the instrument [sc. a crystal microphone] on and off after it has been placed in the proper position, thus eliminating much of the problem of feed-back. 1968Blues Unlimited Dec. 10 Muddy's new album Electric Mud is a morass of feedback,..reverb and every other trick. 1992V. Capel Public Addr. Syst. i. 1 The great bugbear of all public address systems, feedback. 2002I. Sansom Truth about Babies 16 The noise is incredible. The feedback, it's like Hendrix. |