matlab里的关于maple的问题

Question

syms t w %定义两个符号变量t,w
Gt=sym('Heaviside(t+1)-Heaviside(t-1)'); %产生门宽为2的门函数
Fw=fourier(Gt,t,w); %对门函数作傅氏变换求F(jw)
FFw=maple('convert',Fw,'piecewise'); %数据类型转换
FFP=abs(FFw); %求振幅频谱| F(jw)|
ezplot(FFP,[-10*pi 10*pi]);grid; %绘制函数图形，并加网格
axis([-10*pi 10*pi 0 2.2])
为什么把函数式换成'0.018*exp(45*t)*cos(2*pi*3.89*100000*t)*[1-heaviside(t-0.028)]+0.088*exp(-11*t)*cos(2*pi*6.6*10000*t)*[heaviside(t-0.028)]‘的时候却出现报错：??? Error using ==> sym.maple
Error, (in inttrans/fourier/main) invalid input: inttrans/fourier/lookup expects its 1st argument, expr, to be of type algebraic, but received [1-Heaviside(t-7/250)]

Error in ==> sym.fourier at 74
F = maple('map','fourier',f,x,w);
大神解答

Answer 1

是你matlab版本的问题，去下载maple toolbox就可以解决。新版本默认不支持maple了。

Answer 2

老天呐追问

把函数式改成'0.018*exp(45*t).*cos(2*pi*3.89*100000*t).*[1-heaviside(t-0.028)]+0.088*exp(-11*t).*cos(2*pi*6.6*10000*t).*[heaviside(t-0.028)]‘，就是把各函数之间的相乘，由‘*’改成‘.*'，运行后又出现错误：??? Error using ==> sym.sym>char2sym
Not a valid symbolic expression.

Error in ==> sym.sym at 92
S = char2sym(x);
求大神解答