说明：  Bit Error Rate analysis of an Extended Receiver for Rectangular PAM. The performance of a digital communication system in the presence of additive white Gaussian noise (AWGN) can be assessed by the measurement of the bit error rate (BER). The Simulink model provided is a rectangular polar pulse amplitude modulation (PAM) baseband system with an AWGN channel and an extended sample and hold receiver with a low pass filter. An extended receiver has an odd number of sample and hold circuits. What remains to be answered is if such a receiver would provide a more desirable BER than that of a simple S/H receiver.