Patent ID: 8842720
Filing Date: 2014-09-23
Classification: H03F,H04L

Abstract:
1. A method for pre-equalizing a digital modulated RF signal, the method comprising: receiving an input stream of symbols (x(i)) representing a phase change and magnitude of an RF signal, wherein the magnitudes of the symbols in the input stream are constant and the phase changes of the symbols in the input stream encode digital information, and adjusting the input stream of symbols to reduce inter-symbol interference in transmission of an RF signal modulated according to the input stream, thus obtaining an equalized stream of symbols (x′(i)), each symbol of the equalized stream representing a phase change and magnitude of an RF signal, the adjusting comprising iteratively determining a next symbol of the equalized stream (x′(n)) after receiving a next symbol of the input stream (x(n)) by multiplying said next symbol of the input stream (x(n)) with a next adjusting real number (a(n)), multiplying a previous symbol of the input stream (x(n−1)) with a previous adjusting real number (a(n−1)), said previous symbol being received directly before said next symbol of the input stream, and computing the next symbol of the equalized stream from the multiplied next symbol of the input stream and the multiplied previous symbol of the input stream, wherein the equalized stream is defined by the following formula:  with the value of a(n) defined recursively as: wherein x′(n) represents the equalized stream, α(n) represents an adjusting stream, and p represents a model of the RF channel.