Novel Distortion Compensation Scheme for Multichannel Direct RF Digitization Receiver

This paper presents the analysis of the nonlinear distortion model of Low Noise Amplifier (LNA) for direct RF digitization receivers (DRF-RX) and proposes a novel compensation technique for receivers working in multi-channel mode
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. With the proposed design the distortion is suppressed by using a linear reference receiver with a least mean square (LMS) filter. As the major advantage, the distortion suppression is performed after the down-converter so all high-order distortion components are automatically phased out. Furthermore, as the signal is fully processed at a low sampling rate, our proposed scheme is much simpler and the circuit inherently consumes less energy and is more compact, compared to the prior arts.To demonstrate the proposed technique, a direct RF digitization UHF receiver with QPSK modulation has been built and modeled in Matlab. The simulation results show that we could achieve an improvement of ~30 dB in signal SFDR (Spurious-free dynamic range) with the standard two-tone test case, and a reduction of 1000 times in the bit-error-rate (BER) in comparison with the non-compensation receiver.