分别产生符合下列要求的眼图，输入调制方式为2PAM和4PAM，符号率为1Hz，等效信道滤波器为升余弦滚降成形滤波器(缺省滚降系数为0.5)：
1)　　无噪声和信噪比为20dB的加性高斯白噪声
2)　　升余弦滚降系数分别为0.5和1
3)　　受到码间串扰影响，信道参数可设为：ch=[0.9806; -0.1961]；(In accordance with the following requirements of eye respectively, the input modulation mode is 2PAM and 4PAM, the symbol rate is 1Hz, the equivalent channel filter for raised cosine shaping filter (default roll off factor of 0.5):
1) additive Gauss white noise with noise free and signal to noise ratio of 20dB
2) raised cosine roll down coefficients are 0.5 and 1, respectively
3) affected by intersymbol interference, the channel parameters can be set as follows: ch=[0.9806; -0.1961];)