仿真4-PAM载波调制信号在AWGN信道下的误码率和误比特率性能，并与理论值相比较。假设符号周期为1s，载波频率为10Hz，每个符号周期内采样100个点。

-Simulation 4-PAM modulation signal in AWGN channel bit error rate and bit error rate performance, and compared with the theoretical value. Assuming symbol period for 1s, the carrier frequency is 10Hz, each symbol period sampling 100 points.