帮我看看我的matlab程序出了什么问题,为什么第三个图出现不了

帮我看看我的matlab程序出了什么问题,为什么第三个图出现不了
fm=20*10^6;%medium frequency
bm=5*10^6;%signal band
ts=100*10^(-6);%sweeping period
fs=60*10^6;%sampling frequency
fd=2e6;%doppler frenquency
t=0:1/fs:ts;
s=cos(2*pi*(fm-0.5*bm).*t+2*pi*bm/(2*ts).*t.^2);%signal sampling
subplot(311);
plot(t,s)
title('调频信号时域图');
xlabel('t/100us');
s_len=length(s);
ws=fft(s);
f=(0:length(ws)-1)'*fs/length(ws);
subplot(312);
plot(f,abs(ws))%frequency spectrum of sgnal
title('调频信号频域图');
xlabel('f/10MHz');
n=28;
ff=[0.05 0.95];
m=[1 1];
b=firls(n,ff,m,'hilbert');
ss=conv(s,b,'same');
susb=0.5*s.*cos(2*pi*fd.*t)+0.5*ss.*sin(2*pi*fd.*t);
wsusb=fft(susb);
f1=(0:length(susb)-1)'*fs/length(susb);
subplot(313);
plot(f1,abs(wsusb))%frequency spectrum of handled signal
title('调频信号多普勒频移');
xlabel('t/10MHz');
报错信息为
Error in ==>
ss=conv(s,b,'same');
请大侠们帮我解释一下,在下感激不尽
不好意思,漏写错误信息了,完整信息为
Error using ==> conv
Too many input arguments.
Error in ==>
ss=conv(s,b,'same');