Scanning systems which produce records of electromagnetic input signals are usually subject to random impulse interference which may seriously degrade the records. An impulse noise suppressor employing digital techniques has been developed which has general applicability to such systems and which has been employed with success in a meteor radar installation and a thermal infrared scanning system. The results of field tests are presented verifying the usefulness of the suppressor with the meteor radar system. When used in conjunction with a digital signal averager the improvement is equivalent to a tenfold increase in transmitter power, with the added advantage that the signal output is suitably conditioned for further computer processing.

http://iopscience.iop.org/article/10.1088/0022-3735/9/1/010/pdf

Performance of a digital signal processor with impulse noise suppression (meteor radar detection system appl.)

A method is described for suppressing impulse interference in a signal detection system by recognizing it as a non-Gaussian contribution, not possessing any of the expected signal characteristics. A digital implementation of the method is presented in detail. The performance of a complete signal detection system employing signal integration together with impulse interference suppression is discussed.

http://iopscience.iop.org/article/10.1088/0022-3735/4/5/010/pdf

Impulse noise suppression and digital signal integration

The Sun is a readily accessible source of wideband noise that can be used for the calibration of a wide variety of radio systems. Since 1979 the United States Air Force Radio Solar Telescope Network (RSTN) has performed solar flux observations around noon on eight frequencies between 245 and 15,400 MHz. These fluxes are disseminated by the National Ocean and Atmospheric Administration (NOAA) and are used by many radio and radar system operators to perform system calibration. Little analysis has been performed on the RSTN noon flux values. Here we review the calibration procedures of RSTN and perform statistical tests between the four sites comprising RSTN. For system operators who require precise system calibration the noted variations may be large enough to cast doubt on RSTN flux values for such calibration. However, for many communication systems a calibration within one or two dB is adequate. We discuss the reported variation both in linear and logarithmic terms. When it is possible to used smoothed data the inter‐site variation becomes less of a problem, although the correlation between sites at Ku band (15,400 MHz) still appears excessively large. We update some simple empirical models for wideband solar flux based purely on the 10 cm flux at any time, as these have also been used in solar radio calibration procedures. We give practical advice on the use of solar flux for radio system calibration and make some recommendations that we believe could improve the accuracy and utility of solar radio flux reports.

J A Kennewell

Papers

Impulse noise suppression and digital signal integration

Analysis of the Radio Solar Telescope Network's Noon Flux Observations Over Three Solar Cycles (1988–2020)