| 释义 |
modulation|mɒdjuːˈleɪʃən|
[a. F. modulation (14th c. in Hatz.-Darm.) or ad. L. modulātiōn-em, n. of action f. modulārī to modulate.]
1. The action of forming, regulating, or varying according to due measure and proportion; † measured or rhythmical movement; variation (of light, line, form, etc.) with regard to artistic effect; a softening, tempering, or toning down.
1531Elyot Gov. i. xx, More ouer the emperours that were moste noble, delited in daunsyng, perceyuing therin to be a perfecte measure, whiche maye be called modulation. 1674Govt. Tongue i. 3 To this purpose the infinite wisdom of God ordained Speech, which as it is a sound resulting from the modulation of the Air, has most affinity to the spirit. 1695Woodward Nat. Hist. Earth iv. (1723) 195 The Matter of two or more Kinds being mix'd together, and, by the different Proportion and Modulation of that Matter, variously..diversify'd. 1753Hogarth Anal. Beauty xii. 95 Different kinds of softnings and modulations of the rays of light. 1883C. C. Perkins Ital. Sculpture ii. ii. 124 That delicate modulation of surface treatment which gives high value to the best Florentine metal work. 1888Scribner's Mag. III. 424 It is not the firmness of a line in drawing or sculpture that makes it forbidding; it is the stiffness or poor quality of its modulation.
2. The action of inflecting the voice or an instrument musically; variation of tone or pitch; regulated variety of inflexion in the voice; a particular inflexion or intonation.
1543Traheron Vigo's Chirurg. ii. iii. xv. 60 That it [sc. the uvula] myght gyve modulation or tunynge to the voice. 1646Sir T. Browne Pseud. Ep. vii. xiv. 368 Although the weazon, throtle and tongue be the instruments of voice, and by their agitations doe chiefly concurre unto these delightfull modulations. 1701Grew Cosm. Sacra i. v. §10. 25 The Rings of the Wind-pipe, are fitted for the Modulation of the Voice. 1756–7tr. Keysler's Trav. (1760) IV. 14 Among the singers in Italy..Farinelli indisputably makes the greatest figure for the fineness and modulation of his voice. 1797Mrs. Radcliffe Italian i, All the sensibility of character that the modulation of her tones indicated. 1824L. Murray Eng. Gram. (ed. 5) I. 361 By modulation is meant that pleasing variety of voice, which is perceived in uttering a sentence, and which, in its nature, is perfectly distinct from emphasis, and the tones of emotion and passion. 1859Geo. Eliot A. Bede i With the same gentle modulation of voice as when he spoke to Seth. 1866Huxley Physiol. vii. (1869) 205 The modulation of the voice into speech is effected by [etc.].
3. The action of singing or making music; an air or melody; pl. musical notes or sounds. Now rare.
1398Trevisa Barth. De P.R. xix. cxxxi. (1495) 941 Symphonia is temperate modulacion accordynge in sownes highe and lowe. c1425St. Mary of Oignies ii. xi. in Anglia VIII. 178/14 Oure lorde..fillid hir herte wiþ myrþe, and hir lippys wiþ modulacyone. 1616Bullokar Eng. Expos., Modulation, a pleasant tuning or sweete singing. 1624Donne Serm. ii. (1640) 12, I will sing of thy mercy and judgement, sayes David; when we fixe our selves upon the meditation and modulation of the mercy of God, even his judgements cannot put us out of tune. 1656Blount Glossogr., Modulation,..a pleasant tuning, a singing or playing by number or measure. 1728–46Thomson Spring 608 Innumerous songsters, in the freshening shade Of new-sprung leaves, their modulations mix Mellifluous. 1816T. L. Peacock Headlong Hall xi, To ring to the profaner but more lively modulation of Voulez vous danser, Mademoiselle!
4. Mus.
a. Hist. In the ecclesiastical modes: Each of certain notes in each mode, on which a phrase of melody must begin and end (see quot.).
1880Grove's Dict. Mus. II. 351/2 The intermediate phrases can only begin, or end, on one of another set of notes, called its Modulations. Of these Modulations, four—the Final, Dominant, Mediant, and Participant—are of more importance than the rest, and are therefore called Regular. But as the constant reiteration of these four notes would prove intolerably monotonous, in a Melody consisting of very numerous phrases, other notes, called Conceded Modulations, are added to them.
†b. Composition or performance of music, management of melody and harmony, in a particular ‘mode’ or key. Also, a chord or succession of notes, an air or melody (cf. 3). Obs.
1721A. Malcolm Treat. Mus. xiii. 441 Under the Term of Modulation may be comprehended the regular Progression of the several Parts thro' the Sounds that are in the Harmony of any particular Key as well as the proceeding naturally and regularly with the Harmony from one Key to another. 1782Burney Hist. Mus. II. 412 As to the Modulation, it is so monotonous, that little more than two chords are used throughout the Canon [‘Sumer is i-cumen in’]. 1797Encycl. Brit. (ed. 3) XII. 191/2 Modulation..frequently means no more than an air, or a number of musical sounds properly connected and arranged. Ibid. 511/2 The modulation formed by ut with the octave of sol and the double octave of mi, sung one after the other. Ibid. 512/2 This modulation or chord ut, mi♭, sol, ut.
c. In modern use: The action or process of passing from one key to another in the course of a piece; the result of this, as an element in the harmony of the piece; a change of key.
1696Phillips, Modulation, a carrying on a Song in the same Key, sometimes passing out of it, then getting into it again, without offending the Ears. 1721A. Malcolm Treat. Mus. xiii. 450 Having thus explained the Nature of Modulation from one Key to another. 1782Burney Hist. Mus. II. 163 note, The modulation from D major to C is rarely found in modern music. Ibid. 164 The following specimens of Chromatic Modulation, ascending and descending. 1839Penny Cycl. XV. 296/2 Modulation may be divided into Simple, Chromatic (or extraneous), and Enharmonic. 1889Prout Harmony (ed. 10) xiv. §371 By..enharmonically changing one or more of its notes it [the chord of the Diminished Seventh] can be used for modulation between any two keys.
5. transf. Melodious composition in prose or verse; harmonious treatment of language.
1759Johnson Idler No. 63 ⁋7 Then begin the arts of rhetoric and poetry, the regulation of figures, the selection of words, the modulation of periods. 1779–81― L.P., Waller Wks. II. 269 The Poets of Elizabeth had attained an art of modulation, which was afterwards..forgotten. 1841D'Israeli Amen. Lit. (1867) 476 A master in the art of versification was struck by our poet's modulation.
6. Arch. The proportioning or regulating of the parts of an order by the module (see module 4).
1665J. Webb Stone-Heng (1725) 62 Ornaments made from the Rule of the Dorick Modulation. 1842Gwilt Archit. Gloss., Modulation, the proportion of the different parts of an order.
7. a. Chiefly Telecommunications. The process of modulating a wave or beam (see modulate v. 5 a) in order to impress a signal upon it; the extent to which a modulated carrier wave is varied; also, the wave-form or signal so impressed. Cf. demodulation.
Freq. preceded by a n. denoting either (a) the characteristic of the carrier wave that is varied (as in frequency modulation), or (b) the method by which the modulation is applied (as in grid modulation).
1919Proc. IRE VII. 193 (heading) Modulation. 1921J. Scott-Taggart Thermionic Tubes xiii. 355 Two general methods of modulation are used at present; either the amplitude of the continuous waves is varied by the microphone, or the wave-length is altered... Sometimes both wave-length and amplitude modulation occur at the same time. 1924W. James Wireless Valve Transmitters ix. 200 The strength of the note received is dependent..on the degree of modulation—that is, on the extent to which the amplitude of the oscillations vary. 1931Proc. IRE XIX. 2146 Amplitude modulation by means of vacuum tubes can be effected in two different ways: as plate modulation or grid modulation. 1932Ladner & Stoner Short Wave Wireless Communication v. 73 Rectification is essential at the receiver, for the purpose of extracting the modulation. 1943F. E. Terman Radio Engineers' Handbk. vii. 581 In phase modulation, intelligence is transmitted by varying the phase of the transmitted wave. 1949H. E. Penrose Princ. & Pract. Radar xvi. 310 The klystron and the reflex klystron depend for their action primarily upon velocity modulation of the electron stream. 1952[see modulate v. 5 a]. 1953W. A. Edson Vacuum-Tube Oscillators xvi. 386 The presence or absence of an output signal, in conjunction with an appropriate code, permits the communication of information. Such keying represents the simplest possible form of modulation, and is applicable to all kinds of oscillators. 1962A. Nisbett Technique Sound Studio vi. 107 The equipment is lined up on a standard 1,000 c/s tone sent from the studio. The standard used is 1 milliwatt in 600 ohms..and is equivalent to 40% modulation at the transmitter. 1968Radio Communication Handbk. (ed. 4) ix. 5/2 Choke modulation employs a choke as the coupling impedance between the modulator and the r.f. stage. 1972Sci. Amer. Sept. 101/2 The most widely used processes of modulation are amplitude modulation (AM), frequency modulation (FM), pulse amplitude modulation (PAM) and pulse code modulation (PCM).
b. transf. The action or result of varying the magnitude, degree, etc., of something.
1964Science 15 May 816 Modulation of transfer RNA species can provide a workable model of an operator-less operon. 1970R. W. McGilvery Biochem. xxiii. 543 (heading) Regulation [of metabolism] by modulation of enzyme activity. 1971Physics Bull. July 388/1 An acoustic wave produces a periodic modulation of the density of the medium. 1973Sci. Amer. Aug. 50/2 The conduction between them can be controlled by the modulation of the charge in a channel between them.
c. attrib., as modulation envelope, the envelope of an amplitude-modulated carrier wave; modulation factor = modulation index; modulation frequency, the frequency of a wave used to modulate another wave; modulation index, a coefficient representing the degree of modulation of a carrier wave; spec. the ratio of the difference between the maximum and minimum frequencies of a frequency-modulated carrier to the frequency of the modulating signal.
1930Proc. IRE XVIII. 2161 If this leakage is slower than the rate at which the modulation envelope decreases, then the condenser voltage cannot follow the modulation envelope. 1950P. Parker Electronics x. 301 In the radio frequency stages of a receiver, distortion is important only in so far as it makes the modulation envelope of the signal voltage different from the wave-form of the modulating sound. 1970J. Earl Tuners & Amplifiers ii. 47 To the centre-tap..is fed the mono and subcarrier stereo components, and the action of the switching transistors..is such that a ‘modulation envelope’ is formed, one side carrying the left-channel information and the other side the right-channel information.
1939Amat. Radio Handbk. vi. 93/1 When using a continuous pure tone (sine wave) for modulating..the percentage modulation can be obtained by the Heising formula:—If IO = R.M.S. value of unmodulated aerial current..IM = ditto when modulated. m = modulation factor. Then IM = IO√ (1 + m2/2).
1930Proc. IRE XVIII. 2162 The rate of decrease of the modulation envelope depends upon the modulation frequency f and the degree of modulation m of the signal. 1962Simpson & Richards Physical Princ. Junction Transistors xviii. 453 The carrier and modulation frequencies are applied to one or both of the input electrodes.
1930B. van der Pol in Proc. IRE XVIII. 1200 The whole practical problem of the amount of disturbance arising from frequency modulation depends therefore upon the value of the ratio m = Δω/p of the absolute frequency deviation to the imposed audio frequency p. Owing to the importance of this parameter m..it may be found useful to designate it by a special name for which we suggest the expression ‘frequency modulation index’. 1931H. Roder in Ibid. XIX. 2151 B. van der Pol has introduced the expression ‘modulation index’ for mf. We shall use this term for both mp and mf [where mp represents the degree of phase modulation in a wave i = Ao sin (ωot + mp sin µt)]. 1974Encycl. Brit. Macropædia XVIII. 91/2 The larger the modulation index (and hence the wider the bandwidth required for transmission), the more effectively FM performs.
8. Biol. Reversible variation in the activity or form of a cell in response to a changing environment.
1939P. Weiss Princ. Devel. i. 94 This physiological, strictly nonprogressive fluctuation of a cell in response to its environmental conditions may be called modulation. It provides for a certain latitude within which a cell can comply adequately with certain variable functional demands of the developed body. 1964N. T. Spratt Introd. Cell Differentiation ii. 20 We..cannot accurately draw a line between differentiations and modulations. 1970Ambrose & Easty Cell Biol. xiii. 441 Hormones are known to affect the synthetic function and the size of certain organs. This is an example of what Weiss has called ‘modulation’. |