请教:PSD曲线变化剧烈说明什么?

shadowying7

自功率谱密度曲线变化的剧烈与平缓能表明什么?请各位赐教!多谢!

[ 本帖最后由 shadowying7 于 2007-9-20 19:18 编辑 ]

wanyeqing2003

PSD表示的是振动信号的频率分量。

fliony

我也想问类似问题
如何分析
曲线说明什么呢

jingrenzhi

找到答案了没?如果PSD表示的是振动信号的频率分布的话,说明振动频率变化太大,但是我没有找到哪本书上说过!

wanyeqing2003

如果功率谱曲线有突出的峰值，也就是峰值两边的曲线变化剧烈，说明是一个窄带随机过程，或者是一个周期振动。

如果功率谱曲线较为平坦，没有变化非常缓慢，这就表明是一个宽带振动。振动具有丰富的频率分量。

jingrenzhi

你好!我现在有一个问题,就是我用不同的方法,求出同一信号的功率谱,不一样,有的方法求出的功率谱曲线有突出的峰值,有的方法求出的功率谱曲线较为平坦，请问为什么?

wanyeqing2003

原帖由 jingrenzhi 于 2007-10-16 19:38 发表
你好!我现在有一个问题,就是我用不同的方法,求出同一信号的功率谱,不一样,有的方法求出的功率谱曲线有突出的峰值,有的方法求出的功率谱曲线较为平坦，请问为什么?

需要把具体处理的方法和数据提供给我们，这样才能帮你解决问题。

其中的可能，采样频率选取的问题，A/D变换的问题，软件本身的问题等。

jingrenzhi

这是我的程序和数据,请帮忙看看!谢谢!
(1)clear
clc
close all hidden
fni=input('wenjian:','s');
Fs=512;
N=1024;
n=0:1/Fs:1;
fid=fopen (fni,'r');
sf=fscanf (fid,'%f',1);
m=fscanf (fid,'%d', 1);
fno=fscanf (fid,'%s',1);
x=fscanf(fid,'%f',inf);
status=fclose (fid);
pyulear(x,15,N,Fs)
(2)clear
clc
close all hidden
fni=input('wenjian:','s');
fid=fopen (fni,'r');
x=fscanf(fid,'%f',inf);
N=1024;
fs=512;
h=spectrum.welch;
Hpsd=psd(h,x,'fs',fs);
plot(Hpsd)
数据附件,不会发,见下一贴!呵呵

jingrenzhi

我把数据做成了文本格式，这样更方便。
                                              ------zhangnan3509

[ 本帖最后由 zhangnan3509 于 2007-10-18 20:40 编辑 ]

jingrenzhi

你真的是太好了!能教给我怎么做的吗?以后我可以少占点版面空间!呵呵!

jingrenzhi

请问这两个程序,所用的方法有啥区别?谢谢

wanyeqing2003

怎么打不开数据？

jingrenzhi

哦!我也不知道!你这样看看!就是占版面太多!:@)
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wanyeqing2003

看了一下数据，只有中间一段数据是有效的。

数据分析时，应该考虑合理地选择数据区间和采样频率。应该说这样的信号应该有比较明显的峰值。

jingrenzhi

请问,针对我那两个程序,处理的结果,怎么不一样?