Patent ID: 6233287
Filing Date: 2001-05-15
Classification: H03D

Abstract:
A method for frequency converting a first digital signal, sampled at a first sampling rate and operating at a first frequency, to a second digital signal operating at a desired frequency, comprising the steps of:modifying and filtering the first digital signal to eliminate unwanted frequencies in the first digital signal and to alter the first sampling rate of the first digital signal by a predetermined factor to generate a modified and filtered first digital signal sampled at a second sampling rate and operating at the first frequency, wherein the step of modifying and filtering comprises the steps of:segmenting the first digital signal into a plurality of digital words of predetermined length,filtering a selected one of the plurality of digital words with a predetermined transfer function to generate a filtered digital word, andcombining a plurality of filtered digital words generated over a predetermined time interval to construct the modified and filtered first digital signal sampled at the second sampling rate and operating at the first frequency;andmixing the modified and filtered first digital signal with a predetermined injection signal to generate the second digital signal sampled at the second sampling rate and operating at the desired frequency.