Abstract

Modulation is one of the fundamental technique required for communication applications. High bit rate, better\nconstellation diagram and effective utilization of bandwidth are the important properties which will be considered in selecting\na modulation technique. One such modulation technique which has these properties is QAM technique. Quadrature\nAmplitude Modulation (QAM) is a combination of two basic modulation techniques amplitude modulation and phase\nmodulation. QAM is widely used in communication applications which come under radio frequency range (such as modems\nover telephone lines, satellite communications, HD television broadcasting and wireless communications etc) because of its\nhigh bit rate, better constellation diagram and effective utilization of bandwidth. Different types of QAM techniques are\nstudied. Designing and implementation of different types of QAMs (16, 32 and 64-QAM) are carried out. In these QAM\ndesigns the basic components used are the MOSFETs. The circuit is analyzed at each stage and resulting waveforms are\nobtained. The bit rate of each QAM is calculated and the comparison is done for different QAMs that are designed. The\nwhole design and implementation of these circuits are carried out using cadence virtuoso software, stimulations are done\nusing spectre circuit simulator and the technology used is CMOS 180nm.