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This article has demonstrated the key elements of digital quadrature modulation. The high speeds available from today's semiconductor processes make it ever more practical to implement modulation functions in digital rather than analog technologies.

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This trend will likely continue as digital semiconductor technology pushes operating speeds ever higher. It should be kept in mind that the end result of implementing analog functions in the digital domain is a time sequence of digital numbers, a natural consequence of the sampling process. However, this number stream must ultimately be converted to an analog waveform to be of any practical use. Thus, a digital-to-analog converter (DAC) must be employed to transform the digital signal into the analog domain. As such, there is still a significant role for analog circuitry, especially DACs. As both sample rate and resolution increase, the requirement for high speed, high resolution DACs becomes ever more apparent.

About the Author

Ken Gentile graduated with honors from North Carolina State University where he received a B.S.E.E. degree in 1996. Currently, he is a system design engineer at Analog Devices Inc. (www.analog.com) where he is responsible for the system level design and analysis of signal synthesis products. His specialties are the application of digital signal processing techniques in communications systems and analog filter design. Ken has been published in several industry trade journals and was a primary contributing author to ADI's “A Technical Tutorial on Digital Signal Synthesis”. Gentile can be reached at ken.gentile@analog.com.