基于MATLAB设计的CIC滤波器的问题

Question

我设计了一个CIC滤波器，我想不用补偿滤波器，直接求它的频谱，可是总是出错，不知道什么原因，是不是滤波器设计的不合理呢，设计的信号是AM信号基带信号为100KHZ，载波信号为1MHZ,采样率为80MHZ，将其抽取到10MHZ.
下面是我的代码
clc;
A0=1;
Al=0.8;
fc=1000000;%载波频率1MHZ
f=100000;%基带信号100KHZ
fs1=80000000;%采样率80MHZ
fs2=10000000;
t=0:1/fs1:0.00009;
mes1=Al*cos(2*pi*f*t);
uam1=(mes1+1).*cos(2*pi*fc*t);
s=awgn(uam1,1);
%CIC滤波器的设计
Fs = 80000000; % Input sampling frequency
Fpass = 0.3e6; % Frequency band of interest
D = 8; % Decimation factor of CIC
d1 = fdesign.decimator(D,'CIC',1,Fpass,65,Fs); %design a cic filter
Hcic = design(d1);
Hd(1) = cascade(dfilt.scalar(1/gain(Hcic)),Hcic);
d2 = fdesign.ciccomp(Hcic.DifferentialDelay, ...
Hcic.NumberOfSections,Fpass,5e6,.005,67,Fs/D); % design a cic compensator filter
Hd(2) = design(d2);
y1=filter(Hd(1),s);
y3=filter(Hd(2),y1);
Pxx2=pwelch(y1,[],[],[],fs2,'twosided');%求s得功率谱
LengthAll2=length(Pxx2);
x2=linspace(-fs2/2,fs2/2,LengthAll2)/1000000;%求一半频率的功率
y2=10*log10([Pxx2(LengthAll2/2+1:LengthAll2)',Pxx2(1:LengthAll2/2)']);
subplot(221)
plot(real(y1),'g');hold on;grid minor;

title('通过CIC滤波器');
subplot(212);
plot(x2,y2,'g');hold on;grid minor;
xlabel('Freq (MHz)');
axis([0,5,-150,-10]);
title('频域对比图');