中文说明：随机噪声是由随机数来表达的，随机数的产生可分为查表法、物理方法和数学递推法。由于精度有限，现有的随机数产生算法均是伪随机数产生算法，即所产生的随机数都有一定的周期性。在实际应用中也没有必要采用真正随机的数，能达到一定程度的随机性就可以了。此处的随机数发生采用计算机中rand()函数的做法
English Description：
Random noise is expressed by random number. The generation of random number can be divided into look-up table method, physical method and mathematical recurrence method. Due to the limited precision, the existing random number generation algorithms are pseudo-random number generation algorithms, that is, the generated random numbers have a certain periodicity. In practical application, there is no need to use the real random number, it can achieve a certain degree of randomness. The random number here is generated by the rand () function in the computer