The Effects of Limiters on the Detection of Narrow Band Signals in Broad Band Noise

摘要

The effects of hard limiting on a narrow-band signal in broad-band Gaussian noise is analyzed. The post-limiting spectrum of the noise is shown to be a function not only of the signal-to-noise ratio (SNR) applied to the limiter but also of the frequency (f sub 0) of the signal within the bandwidth (B) of the noise. The output signal-to-noise ratio is computed for a narrow-band filter following the limiter and centered on the signal frequency. For large input SNR, the output SNR is shown to be improved by a factor of 2 if the signal frequency is greater than B/3 and to be degraded by the factor 4 f sub 0/B if the signal frequency is located in the lower frequency region of the noise band. (Author)