Patent ID: 6052037
Filing Date: 2000-04-18
Classification: H03D

Abstract:
A modulation method in which the frequency band of a transmission signal, consisting of signal points generated at a given modulation rate in accordance with transmission data, is shifted by a desired frequency shift amount, comprising the steps of:(a) shifting the frequency band of said transmission signal by a first frequency shift amount;(b) low-pass filtering an output signal resulting from said step (a) in order to limit said output signal to a frequency band containing baseband and equivalent to an integral multiple of said modulation rate; and(c) shifting the frequency band of an output signal resulting from said step (b) by a second frequency shift amount equivalent to an integral submultiple of a sampling frequency, and wherein:said first frequency shift amount is set so that the sum of said first frequency shift amount and said second frequency shift amount is equal to said desired frequency shift amount.