Accession Number : ADD017991

Title :   Method and Apparatus for Suppressing Linear Amplitude Interference from Bandspread Communication Signals.

Descriptive Note : Patent, Filed 26 Sep 91, patented 27 Feb 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Bond, James W ; Velez, Williams

Report Date : 27 Feb 1996

Pagination or Media Count : 12

Abstract : A method and apparatus are provided for suppressing linear amplitude interference (e.g., on off interference) from a sequence of bandspread communication signals generated by a radio receiver. Each sample is defined as a vector having signal and interference vector components. The interference vector component is such that the amplitude of the interference: (1) is essentially linear, and (2) dominates the signal component. To suppress the linear amplitude interference, a pseudo second derivative is obtained for each sample based upon the current, previous and subsequent sample amplitudes. The pseudo second derivative for each current sample is transformed into a corresponding pseudo second derivative vector based on a symmetric sampling of pseudo second derivatives from previous and subsequent received signal samples. All terms of each corresponding pseudo second derivative vector are summed and averaged to generate a corresponding average enhanced signal gain for each sample. Each corresponding average enhanced signal gain is multiplied by a normalized vector approximately parallel to the corresponding sample's interference vector component. This estimates the signal vector component that is parallel to the interference vector component for each sample as an indication of the desired communication signal. The method and apparatus are effective whenever the amplitude of the interference vector components is approximately linear over the time that the interference is present.

Descriptors :   *RADIO INTERFERENCE, *SUPPRESSION, *PATENTS, RADIO RECEIVERS, SYMMETRY, SAMPLING, VECTOR ANALYSIS, RADIO SIGNALS

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE