Ashok Swaminathan

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—A fast-settling adaptive calibration technique is presented that makes phase noise cancelling 16 fractional-PLLs practical for the low reference frequencies commonly used in wireless communication systems. The technique is demonstrated as an enabling component of a 2.4 GHz ISM band CMOS PLL IC with a 730 kHz bandwidth, a 12 MHz reference, and an on-chip(More)
—A major problem in oversampling digital-to-analog converters and fractional-frequency synthesizers, which are ubiquitous in modern communication systems, is that the noise they introduce contains spurious tones. The spurious tones are the result of digitally generated, quantized signals passing through nonlinear analog components. This paper presents a new(More)
—This paper demonstrates that spurious tones in the output of a fractional-N PLL can be reduced by replacing the 16 modulator with a new type of digital quantizer and adding a charge pump offset combined with a sampled loop filter. It describes the underlying mechanisms of the spurious tones, proposes techniques that mitigate the effects of the mechanisms,(More)
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