摘要：现实生活中的很多信号都是非平稳的，钢琴琴音信号是常见的非平稳信号之一。时频分析方法是研究非平稳信号特征的常用工具，时频分析将一维的时域信号映射到二维的时频平面，形成时间和频率联合分布信息，更全面地体现非平稳信号时频特征。本文研究了时频分析方法的国内外发展现状，对以短时傅里叶变换、小波变换、S变换为代表的常用的时频分析方法进行探索，选取了钢琴琴音低、中、高不同音区的代表乐音和混合音，对每种乐音同时用三种方法分析，比较三种分析方法的优劣，同时进行低、中、高音，单音和混合音的对比，研究三种分析方法的普遍适用性，对用电脑构造的音乐系统进行音乐数字化分析具有重要意义。

关键词  钢琴琴音信号  时频分析  Matlab 

毕业设计说明书外文摘要

Title    The Application of Time-frequency Analysis Method in Piano  Signal Detection                                                 

Abstract：The signal not only has the form in the time domain , in the frequency domain, the frequency domain also has the form of expression. Signals that are difficult to discern in the time domain which can be analyzed by Fourier transform to the frequency domain. Often in the frequency domain , the analysis of music signals easier to finding out their respective characteristics between. Time domain signal can be converted to the frequency domain by Fourier transform, especially in the recent development of discrete Fourier transform, there have been a variety of fast algorithm, especially with the computer, making the calculation of the simplification of the complex rapider, visualization.The main task of this text is to master the basic composition of the piano and its signal characteristics, masering the use of time-frequency analysis method to extract the characteristics of music signals, tone and mixed tone detection. Through the time-frequency analysis method of sound signal, such as STFT, ST, etc., time-frequency characteristic analysis of single-key and multi-key mixed tone is carried out, and the performance of each algorithm is compared in Matlab environment.

Keywords  the piano sound signal  JTFA  matlab

目   次

1 绪论 5

1.1 提出问题 5

1.2 选题研究背景 5

1.3 目前研究现状 6

1.4 本文研究内容 6

2 基础乐理知识 7

2.1 音乐的基础知识 7

2.2 钢琴键盘 8

2.3 音的成分 9

2.4 音符时值 10

2.5 和弦 10

3时频分析方法 11

3.1短时傅里叶分析方法 11

3.2 小波变换分析方法 16

3.3 S变换分析方法 19

4单音和混合音的研究及判定 24

4.1 单音 25

4.2 混合音 29

5 结论 32

6 致谢 33

7 参考文献 34