An approach to analog mitigation of RFI

Per Ödling, Per Ola Börjesson, T Magesacher, T Nordstrom

Research output: Contribution to journalArticlepeer-review

25 Citations (SciVal)


Among all noise sources present in wireline transmission systems we focus on one special type: narrowband radio frequency interference generated by radio amateurs (HAM) and broadcast radio stations. This disturbance, characterized by high power and narrow bandwidth, has the potential of overloading the receiver's analog-to-digital converter (ADC). Once the ADC is in saturation, any countermeasure taken in digital domain will fail. A viable way to face this problem is cancellation using the common-mode signal as a reference. This paper describes in detail an adaptive, mixed-signal, narrowband interference canceller employing a modified recursive least-squares algorithm, which is split into an analog and a digital part. The mixed-signal approach enables the circuit to generate an interference-cancelling signal of several MHz while operating the adaptive algorithm at some kilohertz. Simulation as well as measurement results show a steady-state disturbance suppression of about 35 dB. The convergence speed is high enough to protect the ADC from overloading due to time-variant HAM interference.
Original languageEnglish
Pages (from-to)974-986
JournalIEEE Journal on Selected Areas in Communications
Issue number5
Publication statusPublished - 2002

Subject classification (UKÄ)

  • Electrical Engineering, Electronic Engineering, Information Engineering


  • radio frequency interference
  • cancellation
  • interference mitigation


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