The third edition of the book deals with the subject of digital techniques and systems from the basic circuits (gates) to small scale integrated circuits (SSI), medium scale integrated circuits (MSI), large scale integrated circuits(LSI), and very large scale integrated ciruits (VLSI). Computer-aided design tools and hardware description language VHDL have been introduced to familiarize the readers with the CAD techniques. Key Features : Introduces the CAD tools for digital system design including the hardware description language VHDL; includes new topics such as error-detecting and error-correcting codes, adder with look ahead carry, design of synchronous sequential and asynchronous sequential circuits; discusses issues related to interfacing between ICs of the same logic families and between those of different logic families; quine - Mcluskey method included in chapter 5 on Combinational Circuit Design.; design of complex digital circuits explained using PLDs, PLAs, PALs, CPLDs, and FPGAs; review questions with answers, glossary of key terms, large number of solved examples, and practice problems.