Precoded and polarity‐controlled 3B‐2T code transmission systems

Abstract

In realizing block polarity controlled 3B‐2T code transmission systems, suppression of burst error occurrence due to block polarity control for BSI is the most important problem. This system is more efficient then the conventional AMI code transmission and 4B‐3T code transmission systems. This paper describes a new polarity‐control method, PPC, which makes it possible to eliminate burst errors, and the 3B‐2T code transmission system construction using this method. The proposed polarity‐control burst error elimination is realized by precoding and decoding for polarity indicating signal sequence, and inserting dummy bit at the head of polarity‐control block. The characteristics of twenty‐four 3B‐2T code conversion rules and the four optimum 3B‐2T code conversion rules with average error extension rate 1.6 and average parity detection rate 1.0 are shown. Moreover, word synchronization at demodulation is achieved by detecting the ternary illegal word and its average synchronization detection digit length is shown to be 16. The optimum polarity control block length for an 800 Mbit/s coaxial PCM transmission system is determined to be 32 digits, considering SN degradation caused by waveform distortion due to low‐frequency‐cutoff, timing information disappearance and scapegoat bit insertion which are introduced to satisfy BSI condition.

Analog and digital amplitude‐domain‐multiplexed signal transmission systems using DC‐balance mB‐nB codes

“…The positive and negative analog signals are separated from the ADM signals at the receiver as shown in Fig. (14) [5] ~d -2 reM• ( r + J / 2) · 277max • ft / fo (14) Figure 4 shows the relation between Od and r When the 6B-8B code (nmax • 3) described in Sect. When the 6B-8B code is used, assuming that the word occurrence probabilities are equal and random and that the analog signal is a stationary process, the average low-frequency cutoff distortion noise power Nz (i) (i = 1, 2, 3, 4) for the ith digit in a word of the analog PAM signal, where positive and negative sides are added, is evaluated as shown below, where xa (0 ~ xa ~ a) is the analog signal amplitude for the ADM pulse and ~ denotes the average value N\ 2 > = : 4 X ( 7 ft 1 +6ft 2 +12ft3 +ft4 +6/is) If the analog signal amplitude Xa is uniformly distributed, Eq.…”

“…Nm (number of kinds of mB words) and Nn (number of kinds of nB words) are evaluated by (5) and (6), respectively N,. = 2"' (5) N,.…”

“…The worst intersymbol interference in the digital signal (od) is caused by the low-frequency cutoff in the case of Xd = a and a digital sum variation of 2 x nmax• and is evaluated by Eq. (14) [5] ~d -2 reM• ( r + J / 2) · 277max • ft / fo (14) Figure 4 shows the relation between Od and r When the 6B-8B code (nmax • 3) described in Sect. 3, is used as the mB-nB code, with an order M = 1 of low-frequency cutoff.…”