Digitally Enhanced Software-Defined Radio Receiver Robust to Out-of-Band Interference

Z. Ru, N.A. Moseley, Eric A.M. Klumperink, Bram Nauta

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    239 Citations (Scopus)
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    Abstract—A software-defined radio (SDR) receiver with improved robustness to out-of-band interference (OBI) is presented. Two main challenges are identified for an OBI-robust SDR receiver: out-of-band nonlinearity and harmonic mixing. Voltage gain at RF is avoided, and instead realized at baseband in combination with low-pass filtering to mitigate blockers and improve out-of-band IIP3. Two alternative “iterative��? harmonic-rejection (HR) techniques are presented to achieve high HR robust to mismatch: a) an analog two-stage polyphase HR concept, which enhances the HR to more than 60 dB; b) a digital adaptive interference cancelling (AIC) technique, which can suppress one dominating harmonic by at least 80 dB. An accurate multiphase clock generator is presented for a mismatch-robust HR. A proof-of-concept receiver is implemented in 65 nm CMOS. Measurements show 34 dB gain, 4 dB NF, and 3.5 dBm in-band IIP3 while the out-of-band IIP3 is + 16 dBm without fine tuning. The measured RF bandwidth is up to 6 GHz and the 8-phase LO works up to 0.9 GHz (master clock up to 7.2 GHz). At 0.8 GHz LO, the analog two-stage polyphase HR achieves a second to sixth order HR > dB over 40 chips, while the digital AIC technique achieves HR > 80 dB for the dominating harmonic. The total power consumption is 50 mA from a 1.2 V supply.
    Original languageEnglish
    Pages (from-to)3359-3375
    Number of pages17
    JournalIEEE journal of solid-state circuits
    Issue number12
    Publication statusPublished - 1 Dec 2009


    • receiver
    • CMOS
    • wideband receiver
    • EWI-17379
    • Adaptive interference cancellation
    • Crosscorrelation
    • Multi-phase
    • Linearity
    • SAW-less
    • adaptive signal processing
    • Nonlinearity
    • LMS
    • multiphase clock
    • out-of-band interference
    • Polyphase
    • passive mixer
    • Software-defined radio (SDR)
    • blocker
    • blocker filtering
    • switching mixer
    • interference mitigation
    • low-noise amplifier (LNA)
    • low-noise transconductanceamplifier (LNTA)
    • harmonic rejection
    • mismatch
    • baseband processing
    • digitally assisted
    • digitally enhanced
    • harmonic mixing
    • software radio (SWR)
    • METIS-265273
    • IR-69829
    • robust receiver


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