实用模拟电路设计技术Section3

实用模拟电路设计技术-Section3SECTION5UNDERSAMPLING APPLICATIONSFundamentals of UndersamplingIncreasing ADC SFDR and ENOB using External SHAsUse of Dither Signals to Increase ADC Dynamic RangeEffect of ADC Linearity and Resolution on SFDR andNoise in Digital Spectral Analysis ApplicationsFuture Trends in Undersampling ADCs1SECTION5UNDERSAMPLING APPLICATIONSWalt KesterAn exciting new application for wideband,low distortion ADCs is calledundersampling,harmonic sampling,bandpass sampling,or Super-NyquistSampling.To understand these applications,it is necessary to review the basics ofthe sampling process.The concept of discrete time and amplitude sampling of an analog signal is shown inFigure5.1.The continuous analog data must be sampled at discrete