Reconfigurable IP-Based Spectral Interference Canceller

Abstract

This paper presents a technique to detect and compensate the spurious signals present in a continuous wave (CW) signal which is fixed in frequency and amplitude where the frequency and amplitude of the interfering signal is unknown to the receiver. The interference canceller proposed in this paper is used to detect the presence of standing spurious signals from approximately 0–500 kHz through waveform digitization and processing. This is an alternative solution to the existing analog implementations which function by receiving a certain bandwidth, and creating an out of phase version of the original signal, and then summing the two, cancelling spurs at a specific frequency. The source of these spurs can be internal (ex: self-coupling) or external (ex: nearby transmission stations). As the spur power approaches and exceeds the signal of interest, the receiving system experiences difficulty distinguishing between the intended signal and the spur. To the best of our knowledge, this is the first digital solution to the baseband interference problem. The technique presented in this paper was implemented on ZYNQ-7000 series housed on Xilinx Zedboard development board. The utilization reports show 36% of the Slices, 28% of the LUTs, 43% of the BRAMs, and 36% of the DSP blocks have been used for the complete system. Furthermore, its end-to-end functionality was verified using Xilinx’s Integrated Logic Analyzer (ILA) in removing standing spurious signals, while minimizing distortion to the signal(s) of interest.