Patent ID: 6466277
Filing Date: 2002-10-15
Classification: H04L

Abstract:
A complex digital modulator for generating a carrier modulated by a digital signal comprising:a source of digital signal occurring at a given sample rate; an upsampler responsive to said digital signal, having an output providing samples at an effective sample rate, UR, higher than said given sample rate; a complex modulator having a signal input coupled to the output of the upsampler, and having a carrier input; a source of a repeating sequence of S complex values representing an exponential carrier, with respective complex values occurring at said higher sample rate and applied to said carrier input; wherein a ratio of higher to given sample rate is selected such that the modulator is conditioned to provide a complex modulation about a pseudo-carrier, of frequency PS, which pseudo-carrier has an image frequency such as the sum of UR plus PS, where UR is a positive value, PS represents a complex exponential carrier and S is an integer.