| 释义 |
microphonic, a. and n.|maɪkrəʊˈfɒnɪk|
[f. microphone + -ic.]
A. adj.
1. Pertaining to the microphone.
1878Jrnl. Franklin Inst. CVI. 270 Microphonic Anticipations. 1879N. Eng. Hist. & Gen. Reg. XXXIII. 158 Look at the amazing progress in telegraphic, microscopic, telephonic and microphonic arts! 1881Athenæum 2 July 19/1 Dr. Moser read a paper ‘On the Microphonic Action of Selenium Cells’. 1893Preece & Stubbs Man. Telephony 121 The adoption of the microphonic transmitter in any case necessitates the employment of a battery.
2. a. Characterized by or pertaining to the production of variations in electrical potential in response to sound waves or vibrations.
1879Telegraphic Jrnl. VII. 132/1 The communication of the current with the vibrating plate..is effected by means of two small springs which are lightly pressed by the membrane..which act as a weak microphonic contact. 1919R. Stanley Text-bk. Wireless Telegr. (new ed.) II. vi. 116 With some valve designs there is a microphonic effect in L.F. amplifiers so that the slightest jar given to the apparatus, such as tapping it with the finger or even walking near it, is strongly magnified. 1931Jrnl. Physiol. LXXI. p. xxix, I conclude that the effect is due to some kind of microphonic action by which vibrations produce changes in the potential between different points in the inner ear. 1940A. Wood Acoustics xvii. 478 The microphonic response of the cochlea of a cat to a pure tone of 1000 cycles/sec. is amplified and analysed with a wave analyser. 1951Electronic Engin. XXIII. 429/2 An attempt has been made..to determine the absolute microphonic performance of a valve by relating its electrical output to the frequency and intensity of a sound field in which it is situated. 1970Nature 11 July 184/2 The microphonic response of the cochlea.
b. Of an electrical signal: generated in response to sound waves or vibrations.
1929Proc. IRE XVII. 1621 Microphonic output is caused by relative motions between the various elements of the tube. 1930Zworykin & Wilson Photocells ix. 114 Mechanical vibration of the elements produce what are generally called microphonic noises. 1947Jrnl. Appl. Physics XVIII. 242/2 A simple experiment was set up to check Eq. (7) by mechanically driving a tube and measuring the resulting ‘microphonic’ output signal.
B. n.
1. pl. The science of magnifying sounds. rare.
1846Buchanan Technol. Dict., Microphonics, the science of magnifying small sounds.
2. a. A microphonic signal generated in the cochlea.
1938Stevens & Davis Hearing xii. 319 When the voltage of the cochlear microphonic is plotted against the logarithm of the sound-intensity..the function appears as a sigmoid curve. 1962Laryngoscope LXXII. 432 Is the reduction in amplitude of the cochlear microphonics due to an impairment of sound transmission or to a more direct effect on the organ of Corti? 1974Nature 10 May 162/2 The ‘poor’ cochlear microphonic obtained from BALB/c mice after priming is indicative of hair cell damage.
b. Electronics. An undesired signal or modulation produced (e.g. in a valve) by mechanical vibration. Usu. pl.
1929Proc. IRE XVII. 1622 The simplest test for microphonics consists of an audio-frequency amplifier of fairly high gain, the tube under test being used in the first stage. 1947Jrnl. Appl. Physics XVIII. 245/2 It may well be advantageous to operate the input stage of a high gain automatic volume controlled amplifier with fixed bias to reduce microphonics. 1960IRE Trans. Microwave Theory & Techniques VIII. 372/1 Waveguide under a high acoustical field can definitely contribute to microphonics via the mechanism of phase modulation. 1965Gewartowski & Watson Princ. Electron Tubes v. 152 Vibration of grid wires in grid-controlled tubes is a principal source of ‘microphonics’. |