具有数字镜像抑制的TV CMOS调谐器和解调器

caroline11

Abstract—Superheterodyne TV tuners have been implementedin discrete forms using tunable RF and SAW IF filters. IntegratingTV tuners in CMOS technology without them is a challenging taskto cope with technical issues such as harmonic mixing and image.The image rejection in low- or zero-IF systems has been limited to30–40 dB by analog imperfections such as path gain and phasemismatches. A single-chip low-IF TV tuner solution is proposed sothat the image can be suppressed digitally using an image cancellation technique based on a complex one-tap LMS signal decorrelation algorithm. Programmable digital filtering and video/sound demodulation make a multistandard TV tuner feasible in the 48–860MHz VHF/UHF band. The chip has a maximum gain of 63 dB andan input automatic gain control (AGC) range from 15 to 25 dBwith 0.85-dB steps. It achieves an image and IF rejection of 60 dB,a peak carrier-to-noise ratio (CNR) of 55 dB, and a peak soundsignal-to-noise ratio (SNR) of 44 dB without frequency modulation(FM) de-emphasis. The prototype occupies 6 6 mm2 in 0.25- mCMOS and consumes 1 W at 2.5 V。