【求助】ifft的使用问题
各位大侠，我是个菜鸟，现有一个频域转时域的ifft问题一直搞不懂，恳请指教H11 =
(-3/4*w^4+1095/2*i*w^3+129500*w^2-14950000*i*w-747500000)/(3*w^6-2865*i*w^5-956750*w^4+158800000*i*w^3+14127500000*w^2-742500000000*i*w-24750000000000)
subs(H11,w,-pi:pi/50:pi)
ans =
1.0e-004 *
Columns 1 through 9
0.3023 + 0.0095i 0.3023 + 0.0093i 0.3023 + 0.0091i 0.3023 + 0.0089i 0.3023 + 0.0088i 0.3023 + 0.0086i 0.3022 + 0.0084i 0.3022 + 0.0082i 0.3022 + 0.0080i
Columns 10 through 18
0.3022 + 0.0078i 0.3022 + 0.0076i 0.3022 + 0.0074i 0.3022 + 0.0072i 0.3022 + 0.0070i 0.3022 + 0.0068i 0.3022 + 0.0067i 0.3022 + 0.0065i 0.3021 + 0.0063i
Columns 19 through 27
0.3021 + 0.0061i 0.3021 + 0.0059i 0.3021 + 0.0057i 0.3021 + 0.0055i 0.3021 + 0.0053i 0.3021 + 0.0051i 0.3021 + 0.0049i 0.3021 + 0.0047i 0.3021 + 0.0046i
Columns 28 through 36
0.3021 + 0.0044i 0.3021 + 0.0042i 0.3021 + 0.0040i 0.3021 + 0.0038i 0.3021 + 0.0036i 0.3021 + 0.0034i 0.3021 + 0.0032i 0.3020 + 0.0030i 0.3020 + 0.0028i
Columns 37 through 45
0.3020 + 0.0027i 0.3020 + 0.0025i 0.3020 + 0.0023i 0.3020 + 0.0021i 0.3020 + 0.0019i 0.3020 + 0.0017i 0.3020 + 0.0015i 0.3020 + 0.0013i 0.3020 + 0.0011i
Columns 46 through 54
0.3020 + 0.0009i 0.3020 + 0.0008i 0.3020 + 0.0006i 0.3020 + 0.0004i 0.3020 + 0.0002i 0.3020 0.3020 - 0.0002i 0.3020 - 0.0004i 0.3020 - 0.0006i
Columns 55 through 63
0.3020 - 0.0008i 0.3020 - 0.0009i 0.3020 - 0.0011i 0.3020 - 0.0013i 0.3020 - 0.0015i 0.3020 - 0.0017i 0.3020 - 0.0019i 0.3020 - 0.0021i 0.3020 - 0.0023i
Columns 64 through 72
0.3020 - 0.0025i 0.3020 - 0.0027i 0.3020 - 0.0028i 0.3020 - 0.0030i 0.3021 - 0.0032i 0.3021 - 0.0034i 0.3021 - 0.0036i 0.3021 - 0.0038i 0.3021 - 0.0040i
Columns 73 through 81
0.3021 - 0.0042i 0.3021 - 0.0044i 0.3021 - 0.0046i 0.3021 - 0.0047i 0.3021 - 0.0049i 0.3021 - 0.0051i 0.3021 - 0.0053i 0.3021 - 0.0055i 0.3021 - 0.0057i
Columns 82 through 90
0.3021 - 0.0059i 0.3021 - 0.0061i 0.3021 - 0.0063i 0.3022 - 0.0065i 0.3022 - 0.0067i 0.3022 - 0.0068i 0.3022 - 0.0070i 0.3022 - 0.0072i 0.3022 - 0.0074i
Columns 91 through 99
0.3022 - 0.0076i 0.3022 - 0.0078i 0.3022 - 0.0080i 0.3022 - 0.0082i 0.3022 - 0.0084i 0.3023 - 0.0086i 0.3023 - 0.0088i 0.3023 - 0.0089i 0.3023 - 0.0091i
Columns 100 through 101
0.3023 - 0.0093i 0.3023 - 0.0095i
>> h11=ifft(H11)
??? Function 'ifft' is not defined for values of class 'sym'.
我想问问我这用ifft到底出了什么问题
有什么更好的方法吗？
感谢万分！ 使用之前最好要fft。请看help文件吧 原帖由 jww100 于 2008-9-14 03:12 发表 http://www.chinavib.com/forum/images/common/back.gif
各位大侠，我是个菜鸟，现有一个频域转时域的ifft问题一直搞不懂，恳请指教
H11 =
(-3/4*w^4+1095/2*i*w^3+129500*w^2-14950000*i*w-747500000)/(3*w^6-2865*i*w^5-956750*w^4+158800000*i*w^3+14127500000*w^2 ...
你的里面H11的结果在ifft计算时不是数组，任然是变量，ifft（ans）这样应该可以了吧。 感谢"yelv123"
页:
[1]