Anonymous asked in 社會與文化語言 · 2 decades ago





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  • 2 decades ago
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    Pulse length 又叫 pulse duration,定義如下

    1. In a pulse waveform, the interval between (a) the time, during the first transition, that the pulse amplitude reaches a specified fraction (level) of its final amplitude, and (b) the time the pulse amplitude drops, on the last transition, to the same level. (脈衝的第二次振幅抵達第一次振幅的所需時間)Note: The interval between the 50% points of the final amplitude is usually used to determine or define pulse duration, and this is understood to be the case unless otherwise specified. Other fractions of the final amplitude, e.g., 90% or 1/e (where e = 2.71828. . .), may also be used, as may the root-mean-square (rms) value of the pulse amplitude. Deprecated synonyms pulse length, pulse width.

    2. In radar, measurement of pulse transmission time in microseconds, that is, the time the radar's transmitter is energized during each cycle. [JP 1-02]

    wavelength 定義如下 : The distance between points of corresponding phase of two consecutive cycles of a wave. (一個波中兩個相關相位間的距離)。

    。看起來好像是脈衝是以時間來度量的,例如測量行星距離用的Sephied就是一種脈衝,還有Doppler Effect 也是以時間為度量來標定距離和物体的速度(定義中的第二個有寫是以微秒計),至於波長wave length好像只是用長度單位來計算沒有用到以「時間」來計算,好像也很少被拿來做測量的依據。


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