GSM TCH全速话音信道仿真（基带）

				%绘制不同信噪比下的误码率曲线图
				echo on
				clear all
				close all
				snr_in_DB=0:2:10;
				for i=1:length(snr_in_DB)
				   [class1(i),class2(i),signal(i)]=PrimePe(snr_in_DB(i));  %返回三组误码率
				end
				semilogy(snr_in_DB,class1,'g*',snr_in_DB,class2,'b*',snr_in_DB,signal,'r*'); %绘图
				legend('class I','class II','class I+II');