A&A Supplement Series, Vol. 126, November II 1997, 161-167

Received December 10, 1996; accepted February 21, 1997

Spectral detector for interference time blanking using quantized correlator

R. Weber - C. Faye - F. Biraud - J. Dansou

Send offprint request: R. Weber e-mail: weber@lesi.univ-orleans.fr
  LESI-ESPEO, Université d'Orléans, 45000 Orléans, France
  ETIS-ENSEA, 95000 Cergy-Pontoise, France
  Unité Scientifique de Nançay, Observatoire de Paris, 1 Place Jules Janssen, F-92195 Meudon Principal Cedex, France
  GTR-IUT de Blois, 41 000 Blois, France

Abstract:

Given the large flow of data to be processed, quantized correlators are widely used in radio astronomy. Unfortunately, the occurrence of non-Gaussian interference combined with a coarse quantization can strongly alter the shape of the estimated spectra. The final spectral estimation can be preserved by blanking the correlator in real-time. A new interference detection criterion is proposed within this framework. It uses the real-time capabilities of correlators and compares contaminated and non-contaminated correlation functions. No a priori information on the interfering signals is required. Simulations, using synthetic and actual data, are presented. This new technique of real time detection can significantly improve the quality of spectral line observations.

keywords: instrumentation: miscellaneous -- methods: data analysis -- techniques: spectroscopic

• 1. Introduction
• 2. Generalized chi-square test () theory
• 3. Application of to RFI detection
• 4. Evaluation of the reference vector and the covariance matrix
• 5. Implementation
• 6. Performances
• 7. Conclusion
• References