Accession Number:

ADA218423

Title:

Optimum Memoryless Nonlinear Transformation for Weak Narrowband Signals in Noise

Descriptive Note:

Technical rept.

Corporate Author:

NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT

Personal Author(s):

Report Date:

1989-10-01

Pagination or Media Count:

80.0

Abstract:

The optimum memoryless nonlinear transformation for weak narrowband signals in narrowband noise is derived in terms of the joint probability density function of the noise amplitude and phase modulations. The optimization is in terms of maximizing the magnitude of the deflection of the complex envelope at the nonlinearity output, for small signal inputs of arbitrary characteristics. The optimum nonlinearity is complex, in general, meaning that a phase modulation is superposed, in addition to that present at the input to the nonlinearity. A problem with the behavior of the optimum nonlinearity is traced back to a shortcoming in the approximate analysis, and a method for circumventing the problem is presented. Two methods of treating the spurious weak signal component at the nonlinearity output are considered and compared quantitatively. Finally, the optimum nonlinearity for processing phase differences is derived for a particular model of noise statistics and shown to be closely related to an earlier processor. jhd

Subject Categories:

  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE