在大尺度之波浪水槽中觀察造波機所造出之波列，其傳遞至水槽下游時，其前方波列由初始靜水狀態發展至穩定波動形態，在靜水位與穩定段之間有一段非線性且非穩態的波動，吾人稱此波動為波列之波前(wave front)。波前現象是以振幅的調變狀態呈現，而最終形成一類似實際海面的群波現象。了解波前特性可延續探討實際海面上群波或是由靜水面而產生的風浪特性，本研究即針對試驗資料中非線性波前之演化來做探討。
本研究實驗於國立成功大學台南水工試驗所超大型斷面實驗水槽中進行(長300m，寬5m，深5.2m)，針對兩種典型非線性波列之所衍生出之非線性波前演變進行分析探討，分別為給定一主頻之規則波列以及給定兩振幅而頻率存在微小差異成份波組成之雙主頻波列。由於常用的傅立葉頻譜分析只能顯現整體頻率的變化，因此本研究以同時具有頻率域以及時間域分析能力，且對雙主頻波有良好分析能力的小波分析，探討深水非線性波列所衍生的波前之演化。
分析結果證實小波分析在波前演化的區域，無論規則波或是雙主頻波列，皆能良好的展現各時間點尖峰頻率的變化。對照水位時序列與小波能譜等值圖，振幅較高的區域，其尖峰頻率高於穩定段。為更加了解波前內部波動機制，亦探討了相位速度與個別波波浪尖銳度的變化，結果證實於波前的漸變區，水位振幅高者相位速度較慢，水位振幅低者相位速度較快，對照小波能譜等值圖，可發現相位速度較慢的區域其能量分部較為集中。在波前獨立出一前導波群後，前導波群內的頻率、相位速度、最大個別波波浪尖銳度皆漸趨近一穩定值。

We observe the front wave change from the quiet water state to steady wave motion state, when the wave train which are created by wave maker are delivered to the lower reaches of water flume. There is the non-linear and unstable wave between quiet water state and steady state. We call it wave front of wave train. The phenomenon of wave front shows the wave modulation, and finally becomes The phenomenon of wave group looking like real sea level. Due to understanding the characteristic of wave front, we can continue to discuss the wave group at field ocean or the characteristic of stormy waves which is created from quiet water state. We will use the experimental data of non-linear wave front to illustrate the evolution of it on the research.
The experiments were carried out in a super wave flume whose length is 300m, and width is 5m, and height is 5.2m at Tainan Hydraulics Laboratory in National Cheng-Kung University. We analyse the development of non-linear wave front that are derived from two typical non-linear wave train. The two typical non-linear wave train are regular wave and Bichromatic waves. Because the analysis of used Fourier analysis only can show the change in whole frequency, we decide to use wavelet analysis that have analytical ability of frequency and time domain, and also have good ability to analyse Bichromatic waves. We discuss the development of wave front that are derived from deep-water non-linear wave train by using it.
From the result of the wavelet analysis, both regular wave and Bichromatic wave clearly show the change of peak frequency at any time. In wavelet spectrum, the peak frequency of high amplitude is taller than steady section. We also discuss the change of wave steepness and phase velocity.
Contrasted to wavelet spectrum, we find that the power of slow phase velocity become more concentrated. After wave front separate from leading wave, the frequency of phase velocity and the wave's steepness of the biggest wave also turn into stable value.

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