Patent ID: 6570441
Filing Date: 2003-05-27
Classification: H03D

Abstract:
An incoherent demodulator comprising:local oscillator circuitry for producing a pair of orthogonal carriers; a pair of analog mixers for incoherently demodulating a pair of modulated orthogonal signals with said orthogonal carriers to produce a pair of analog orthogonal baseband signals, there being a phase rotation in said analog orthogonal baseband signals resulting from the incoherent demodulation of said modulated signals; a pair of analog-to-digital converters for processing said analog orthogonal baseband signals to produce first and second digital signals; gain controlled circuitry for scaling the first digital signal, said gain controlled circuitry including averaging circuitry to produce a first average value representing an average power of a scaled first digital signal, and a second average value representing an average power of said second digital signal, such that a difference which exists between the average power of the scaled first digital signal and the average power of the second digital signal reduces to zero; and a digital phase shifter for processing first and second output signals of said gain controlled circuitry so that the processed first and second output signals no longer contain said phase rotation.