Industrial Automatic Control Systems and Controllers Annotation << Back Development of the Principle of Multistage Differential Encoding/Decoding in an Optical System With the MOQPSK Modulation Format and Block Encoding of Transmitted Discrete Messages Rudnev A.N. Based on the properties of algebraically coupled sequences, the development of the method of multiple differential encoding/decoding (MDCD) of a binary information sequence is proposed, which allows to increase the energy effi ciency of the MOQPSK system with block coding. A con-dition has been determined under which MDCD does not reproduce demodulation errors. The results of a comparative analysis of MOQPSK systems with different MDCD parameters and BCH(7.4) and BCH(15.5) codes are presented. The analysis was carried out by software simula-tion modeling of systems in the SystemView environment, and the simulation results are presented in the form of graphs of the dependence of Pb on the Eb/N0 ratio. Keywords: optical communication systems; 100G technology; spectral effi ciency; algebraically coupled sequences; multiple differential encoding/decoding; MOQPSK; block coding; energy gain; software simulation. DOI: 10.25791/asu.8.2024.1526 Pp. 36-40.