QUADRATIC DETECTORS FOR ENERGY ESTIMATION

The estimation of signal energy is an important part of physics and si gnal processing, A commonly used energy estimate in signal processing is instantaneous energy that is defined by the square of the signal ma gnitude at time t, i.e., \x(t)\(2). For a noisy signal, a standard ene rgy detector, which consists of a linear time-invariant (LTI) filter f ollowed by a magnitude-squared operator, is commonly used to reduce no ise and extract signal energy in a certain frequency band. However, du e to the temporal response of the LTI filtering, this energy estimate is smeared in time, In addition, it is unclear how this estimate relat es to the physical energy in the system that produced the signal, In t his paper, we propose simple quadratic systems producing frequency-sel ective energy estimates and effective noise reduction with little or n o smearing in time, We introduce the new concept of quadratic detector s, discuss desirable time and frequency resolution properties of a gen eral quadratic detector, and study five different applications to demo nstrate the simplicity of quadratic detector design and implementation .