| 释义 |
ˈfly-back
[f. verbal phr. to fly back (see fly v.1 9 c).]
1. In a stop-watch or chronograph, the return of the hands to zero. Usu. attrib.
1888Phil. Mag. 5th Ser. XXV. 263 The fly-back chronograph enables time to be measured to 1/5th second, without taking the eye for one moment off the object to be watched. 1903F. J. Garrard Watch Repairing xix. 200 (caption) Fly-back work of chronograph. 1923W. I. Milham Time & Timekeepers xv. 250 A double split-second fly back stop watch..gets out of order quite easily. 1929G. H. Baillie Watches x. 233 A watch with fly-back minute hand, which..flies back to 0 as soon as it reaches 60. 1953W. J. Gazeley Watch & Clock Making & Repairing xiv. 315 Another arrangement met with in some stop watches..is where a separate push-piece is used for the fly-back action.
2. a. The return of the scanning spot in a cathode-ray tube to the starting point after the end of a line or frame. Freq. attrib. b. The portion of each cycle of a saw-tooth wave-form in which the signal diminishes.
1934Jrnl. Inst. Electr. Engin. LXXV. 66/1 The arrangement..constitutes a time base which provides a scanning sweep..and a rapid fly-back. 1948T. Soller et al. Cathode Ray Tube Displays iv. 133 The flat portion [of the waveform] is the ‘quiescent’ voltage and the portion that follows the rise is the ‘return’ or ‘flyback’. 1950Electronic Engin. XXII. 55 The flyback time in these tests was about one-seventh of the sweep time. 1957Amos & Birkinshaw Television Engin. I. i. 15 During the time occupied by each horizontal traverse and fly⁓back the beam moves downwards. |