1.Signal cycle is not there,but continued for some time,not repeated,if the transition process,blasts,the landing gear while landing signals,such signals can become non-periodic signals.Analysis of non-periodic signals ideas :in the time domain,when the cycle T1 → ∞,periodic signals into non-cycle signal; in the frequency domain signal cycle in the spectrum T1 → ∞ limit,and non-periodic signals into a spectrum,Fourier transform.2.In the time domain signal compression Europium times (Europium "1),in the frequency domain band widening,one-amplitude compression Europium times; Instead signal in the time domain expansion (Europium "1),in the frequency domain will lead to narrow frequency band,but the amplitude increased.