[MATLAB数学相关] mtimes和mpower的问题，

[biscu.it]

我也眼花了，我不知道要去哪里问= =

??? Error using ==> mtimes
Inner matrix dimensions must agree.

??? Error using ==> mpower
Matrix must be square.

我在写我的程序时候出现了这些，
然后我也google了说什么家点点，
例如.^2 还是x.*y之类的，
我其实也不太清楚这些怎么看，
我乱加一通结果导致不一样的程式出来的图都一样了，
有谁可以帮我解答？

目前我程序这个样子：

%physical properties of the helmholtz resonator
Vc=0.006868125; %volume of the cavity (m)
a=0.025; %neck radius (m)
Ln=0.015; %neck length (m)
Sn=pi*a^2; %cross sectional area of the neck (m^2)
rho=1.225; %density of air @ 15degC (kgm^(-3))
c0=340.29; %speed of sound @ 15degC (ms^(-1))

%defining plotting interval for the passive helmholtz resonator
fs=1; %define start frequency
ff=500; %define finish frequency
step=1; %frequency step size
f=fs:step:ff; %define frequency interval and step size

%effective properties of the helmholtz resonator
Leff=Ln+1.7*a; %effective neck length for flanged HR
Meff=rho*Sn*Leff; %effective mass for the lumped of air
keff=rho*(c0^2)*(Sn^2)/Vc; %effective stiffness in the cavity
kwav=(2*pi*f)/c0; %wave number
Rr=rho*c0*kwav.^2*Sn^2/(2*pi); %radiation resistance
Q=2*pi*sqrt(Vc*(Leff/Sn)^3); %quality factor for flanged HR
f0=sqrt(keff/Meff)/(2*pi); %w0=resonance frequency (w=2*pi*f)
Rw=f0*2*pi*Meff/Q; %thermoviscous resistance

%orifice impedance
Zn=(Rr+Rw)+1i*(2*pi*f*Meff); %orifice impedance

%actuator dynamics for secondary speaker
Ea=0.04; %actuator damping coefficient
Wa=3456; %actuator natural frequency in rads^-1
Ga=1; %defining gain constant
Ha=(1i*2*pi*f*Ga)/((1i*2*pi*f).^2+2*Ea*Wa*(1i*2*pi*f)+Wa^2); %actuator dynamics

%controller transfer function

Kp=4;
那两个程式也有用到这一个variable- -
可是目前的状况，当我改Kp时候，
plot完全不动，所以是出问题了= =+

%value for Kp
Ns=Kp; %numerator for the controller transfer function
Ds=1; %denomenator for the controller transfer funtion
Hc=Ns/Ds; %controller transfer function

%pressure amplification of the resonator (pressure in the cavity/external driving pressure)

Case 1：P=(Ds-Zn*Ha*Ns)./(Ds*(Zn.*(1i*2*pi*f)*(1/keff)+1));
Case 2：P=Ds./(Zn.*1i*2*pi.*f*(1/keff).*Ds+Ds+Zn.*Ha.*Ns);
程序的所有都是一样的，除了这一行，
可是当我plot的时候，这两个出现的plot是一模一样，
我不知道哪里出错了= =+

%the equivalent of pressure ratio P=Pc/Ps
Pmag=sqrt(real(P).^2+imag(P).^2); %magnitude of the pressure ratio
Pphase=atan(imag(P)./real(P)); %phase of the pressure ratio
PdB=20*log10(Pmag); %magnitude in dB (level of sound)

%plotting command for the bode plot of passive helmholtz resonator
subplot(2,1,1)
plot(f,PdB) %plotting magnitude in dB
Title('Bode plot of activeHR-case 1')
xlabel('Frequency(Hz)')
ylabel('Magnitude(dB)')
subplot(2,1,2)
plot(f,Pphase*(180/pi)) %plotting phase in degrees
xlabel('Frequency(Hz)')
ylabel('Phase(deg)')