Publications (2)0 Total impact
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Conference Proceeding: A software-defined radio receiver architecture robust to out-of-band interference
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ABSTRACT: In a software-defined radio (SDR) receiver it is desirable to minimize RF band-filtering for flexibility, size and cost reasons, but this leads to increased out- of-band interference (OBI). Besides harmonic and intermodulation distortion (HD/IMD), OBI can also lead to blocking and harmonic mixing. A wideband LNA amplifies signal and interference with equal gain. Even a low gain of 6dB can clip OdBm OBI to a 1.2V supply, blocking the receiver. Hard-switching mixers not only translate the wanted signal to baseband but also the interference around LO harmonics. Harmonic rejection (HR) mixers have been used, but are sensitive to phase and gain mismatch. Indeed the HR in shows a large spread, whereas other work only shows results from one chip. This paper describes techniques to relax blocking and HD/IMD, and make HR robust to mismatch.Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009. IEEE International; 03/2009 -
Conference Proceeding: Multipath Polyphase Circuits and their Application to RF Transceivers
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ABSTRACT: Nonlinearity and time-variance in radio frequency (RF) circuits leads to unwanted harmonics and intermodulation products, e.g. in power amplifiers and mixers. This paper reviews a recently proposed multipath polyphase circuit technique which can cancel such harmonics and intermodulation products. This will be illustrated using a power upconverter IC as an example. The upconverter works from DC to 2.4 GHz, and the multipath polyphase technique cleans its spectrum up to the 17th harmonic, keeping unwanted spurious responses more than 40dB below the carrier. The technique can also be useful for other applications, and some possible applications will be discussed.Circuits and Systems, 2007. ISCAS 2007. IEEE International Symposium on; 06/2007
