摘要
本文叙述了一种用于高速光纤数字通信系统中的DmBlM码,并与使用较为广泛的mBnB码和mBlC码作比较。mBnB码的功率谱形状较好,但它存在误码增殖。在高速系统中受器件限制会进一步产生误码,并且随字长增加码变换电路亦将复杂化,而mBlC码某种程度上克服了这些不足。mBlC码的功率谱由连续谱和离散谱两部分组成。当信息码佳号率不为1/2时会出现线状谱,它是产生相位抖动的原因,但它没有误码增殖。mBlC码的电路设计比mBnB简单。 本文着重研讨了DmBlm码。无论信息码传号率为何值,经码型变换后,该种码型传号率均为1/2,以致离散谱线为0,故不会产生相位抖动。由于该种码型功率谱计算较为烦杂,本文给出了用计算机快速相关计算方法获得DmBlM码的功率谱估值。实测所得该种码型功率谱与理论分析亦是一致的。
This paper presents a new DmB1M code for high speed optical fiber communication systems,and compares it with the mBnB code and mB1C code. Although the shape of power spectrum of mBnB code is better,there is bit error multiplication. Because of device limitation,the mBnB code will introduce more bit errors in high speed systems. The code translation cirrcuits also become more complicated with the increase of codeword length. The mB1C code overcomes certain disadvantages of the mBnB code to a certain extent. The power spectrum of the mB1C code is composed of continuous spectrum and discrete spectrum. If the mark rate of information code is not 1/2,the line spectrum will appear. Although the phase jitter will occur due to line spectrum,the bit error multiplication will not come out. The circuit design for the mB1C code is more simple than that for the mBnB code.This paper discusses features with the emphasis on the DmBIM code. Whatever the value of the mark rate of information code is,the mark rate of translated code format is always 1/2. Because the mark rate is 1/2,there are not discrete spectral lines in power spectrum. Therefore phase jitter does not exist. The power spectrum computation of the DmBIM code is rather complicated. Here,a fast-correlation method is given in the paper to estimate the power spectrum of the DmBIM code. The results show that the experimental power spectrum is in good agreement with the theoretical power spectrum.
关键词
功率谱
编码
编码电路
编译码器
power spectrum,coding,coding circuits,code conversion, coder
