| 释义 |
periodograph|pɪərɪˈɒdəgrɑːf, -æ-|
[f. period n. + -o + -graph.]
1. A periodogram; orig. spec. a curve drawn in a periodogram.
1899A. Schuster in Trans. Cambr. Philos. Soc. XVIII. 108 With T as abscissa and S2 as ordinate, draw a curve, which may be called the ‘Periodograph’... It will be seen that the ‘Periodograph’ corresponds exactly to the curve which represents the distribution of energy in the spectrum. 1936Rev. Econ. Statistics XVIII. 63/2 Like the Fourier periodogram, this periodograph will show distinct peaks in the vicinity of real periodicities. 1950Conrad & Pollak Methods in Climatol. (ed. 2) xi. 370 The name ‘periodograph’ is no longer used and Schuster's ‘periodograph’ is now called a ‘periodogram’.
2. An instrument for automatically making a periodogram analysis or Fourier analysis of a curve by optical means.
1930G. A. R. Foster in Jrnl. Textile Inst. XXI. t18 The grating periodograph now described is an instrument which has been..designed for the examination of the irregularities in cotton spinning products... The periodograph is simply a method of carrying out automatically the periodogram analysis..of series of observations for hidden periodicities. 1946Suppl. Jrnl. R. Statistical Soc. VIII. 44 In the correlation periodograph, due to Martindale, the grating of the grating periodograph is replaced by a replica of the curve on a reduced scale. 1973Physics Bull. Mar. 154/2 The ‘Periodograph’ was never applied to the analysis of electron micrographs until Warren (1972) had the ingenious idea of replacing the grating by a series of point sources such as flashlamp bulbs and interposing a micrograph between the bulbs and the final screen. |