| 释义 |
ˌovermoduˈlation Electronics.
[over- 29 b.]
Amplitude modulation that is so great as to result in unacceptable distortion; spec. modulation that causes the amplitude of the carrier to become zero for a significant part of each cycle of the modulating wave.
1927Exper. Wireless & Wireless Engin. IV. 3/1 The strengths of..undesired harmonics relative to the desired fundamental decrease as the modulation ratio α/a is decreased. This is the ground for the term ‘over-modulation’ as a fault at the transmitter. Over-modulation shows, of course, only during the relatively loud passages. 1937Wireless World 2 Dec. 563/1 Over-modulation of broadcast transmitters has been a serious problem. 1962A. Nisbett Technique Sound Studio vii. 132 One of the problems which may arise when tape is re-used is a background ‘chatter’ from the previous recording. This can be due..to overmodulation of the previous recording. 1968Radio Communication Handbk. (ed. 4) ix. 4/2 In frequency modulation there is no condition equivalent to over-modulation.
So overˈmodulate v. trans., to subject to overmodulation; intr., to cause or suffer overmodulation.
1928L. S. Palmer Wireless Princ. & Pract. xi. 418 As long as the modulator be not overworked, the oscillatory current cannot be over-modulated. 1937Wireless World 2 Dec. 563/1 Automatically graduated compression, or limiting,..makes it almost impossible to overload or over⁓modulate the transmitter. 1962A. Nisbett Technique Sound Studio ii. 48 Completely dead sound is difficult to balance: the transient peaks tend to over-modulate. |