Nonlinear Analysis of Angle Demodulation,
Abstract
The angle-demodulation problem is investigated from the viewpoint of nonlinear filtering theory. The mean square error criterion and state-variable representation of Kushner's classical nonlinear approach are adopted. The relationship between the optimum nonlinear filter and certain decoupled implementations is shown. The decoupled implementations are subsequently analyzed and nonlinear effects such as thresholding, cycle skipping, and phase locking are investigated by Fokker-Planck methods. The mean square estimation error is obtained exactly for the first-order signal-to-noise ratios (SNR) and demodulator gains. Linear methods of analysis are shown to lead to erroneous results even when the SNR is large. Since solutions to the Fokker-Planck equation for angle-modulation problems are usually difficult to obtain, an orthogonal projection technique is presented for obtaining approximate solutions. The approximate solutions are shown to compare favorably with simulations above and below threshold for the frequency demodulation of a message with a first-order spectrum. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1972
- Accession Number
- AD0767714
Entities
People
- Francis S. Nakamoto
- Neil J. Bershad
Organizations
- University of California, Irvine