Joe T Sumida

US Patent:

48127868, Mar 14, 1989

Filed:

Sep 28, 1987

Appl. No.:

7/100991

Inventors:

Faramaz Davarian - Los Angeles CA
Joe T. Sumida - Altadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H03C 500
H04L 2712
H04L 2720

US Classification:

332 16R

Abstract:

A method and system is disclosed which provides precise multi-function digitally implementable modulation for a communication system. The invention provides a modulation signal for a communication system in response to an input signal from a data source. A digitized time response is generated from samples of a time domain representation of a spectrum profile of a selected modulation scheme. The invention generates and stores coefficients for each input symbol in accordance with the selected modulation scheme. The output signal is provided by a plurality of samples, each sample being generated by summing the products of a predetermined number of the coefficients and a predetermined number of the samples of the digitized time response. In a specific illustrative implementation, the samples of the output signals are converted to analog signals, filtered and used to modulate a carrier in a conventional manner. The invention is versatile in that it allows for the storage of the digitized time responses and corresponding coefficient lookup table of a number of modulation schemes, any of which may then be selected for use in accordance with the teachings of the invention.