Title :
A fast normalizer
Author :
Cox, Henry ; Pace, Donald
Author_Institution :
Orincon Corp., Arlington, VA, USA
Abstract :
Most detection systems use normalizers for dynamic range compression and to provide estimates of signal-to-noise ratio (SNR) from the total power or energy measurements that generally involve signal-plus-noise. Typically, an average of values in a "noise window" of neighboring bins in frequency, time or space is used to obtain a local noise estimate. A critical problem occurs if one or more of the neighboring bins contains a strong signal. Then, the resulting noise estimate will be too high and the SNR estimate too low, causing missed detections. To overcome this problem, a number of computationally intensive approaches have been developed. These attempt to identify and modify or remove from the average those bins that contain the signal. A new approach to this problem is presented, one that has been implemented by a fast convolution and by simple recursion. It involves use of the harmonic mean to suppress strong signals in the "noise window". A statistical analysis is presented. In general, an order-of-magnitude speed-up is achieved over the best normalizer with little or no loss in performance.
Keywords :
convolution; interference suppression; noise; parameter estimation; signal detection; statistical analysis; SNR estimates; detection systems; dynamic range compression; energy measurements; fast convolution; fast normalizer; frequency; harmonic mean; local noise estimate; missed detections; noise window; recursion; signal plus noise; signal to noise ratio; statistical analysis; strong signals suppression; total power measurements; Background noise; Convolution; Dynamic range; Energy measurement; Frequency estimation; Power harmonic filters; Signal processing; Signal resolution; Signal to noise ratio; Statistical analysis;
Conference_Titel :
Signals, Systems and Computers, 1996. Conference Record of the Thirtieth Asilomar Conference on
Conference_Location :
Pacific Grove, CA, USA
Print_ISBN :
0-8186-7646-9
DOI :
10.1109/ACSSC.1996.600947