求翻译：信号不是周期性出现，而只是持续一段时间，不再重复出现，如过渡过程、爆炸产生的冲击波、起落架着陆时的信号等，把这一类信号看成为非周期信号。是什么意思？

There is not a periodic signal, but only for some time, not repeated, such as the transition process, the explosion shock wave, when the landing gear landing signals, the signal is seen as this type of non-periodic signal.

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The signal is not the periodic appearance, but only continues period of time, no longer duplicates appears, like the transient process, the detonation produces the shock-wave, the landing gear land the time signal and so on, regards as this kind of signal for the non-cyclical signal.

Signal is not periodically appear, but only to remain for some time, no longer repeated, such as the transition process, blast shock wave, landing-landing signal, signals such as non-periodic signals.

Signal is not periodically appear, but only to remain for some time, no longer repeated, such as the transition process, blast shock wave, landing-landing signal, signals such as non-periodic signals.