Signal Enhancement in AM-FM Interference

Abstract

A new approach to interference suppression is developed to enhance the audibility of signals corrupted by amplitude-modulated (AM) and frequency- modulated (FM) tonal interference. The suppression algorithm uses a short-time, least-squares estimation of the parameters of an AM-FM model of the time-varying tonal interference. The method, developed in a sine-wave analysis/synthesis framework, can be integrated with time and frequency modifications for further signal enhancement. Suppression is applied to single and multitone synthetic and actual AM-FM interference, the latter including man-made signals (e.g., siren interference) and those that occur naturally (e.g., biologic interference). The relative advantages and disadvantages of the sine-wave framework in contrast to a short-time Fourier transform overlap-add framework are described. The enhancement techniques are robust in a large range of environments and can be designed to preserve a random noise background. Finally, it is shown that interference suppression on multichannels prior to beamforming enhances beamformer performance.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
May 17, 1994
Accession Number
ADA285114

Entities

People

  • Robert B. Dunn
  • Robert J. Mcaulay
  • Thomas F. Quantieri

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Biomedical
  • C4I
  • Energy and Power Technologies
  • Sensors

DTIC Thesaurus Topics

  • Acoustic Signals
  • Algorithms
  • Amplitude
  • Background Noise
  • Biomedical Research
  • Differential Equations
  • Equations
  • Estimators
  • Frequency
  • Frequency Bands
  • Gaussian Noise
  • Measurement
  • Modulation
  • Sine Waves
  • Test And Evaluation
  • Waveforms
  • Waves

Fields of Study

  • Engineering

Readers

  • Adaptive Control and Estimation with Uncertainty in Dynamic Systems.
  • Radio communications and signal processing.
  • Speech Processing/Speech Recognition.