Signal-to-noise ratios in smooth limiters

Signal-to-noise ratios associated with smooth band-pass limiting and subsequent narrow-band filtering of a periodic signal and random noise are computed. Observed changes in signal-to-noise ratios may be used to estimate detectability losses. The error function is used to represent the limiter characteristic at various degrees of limiting. First-order corrections with an increasing input signal to the signal-to-noise ratios, which are based on the small signal theory, are computed for limiter input noise with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sin x/x</tex> , Gaussian, and exponential correlation functions.