Patent ID: 6466098
Filing Date: 2002-10-15
Classification: H03L

Abstract:
Apparatus for generating an oscillating signal in a desired phase relationship with an input signal, comprising:mixing means arranged to receive a pair of reference signals oscillating at a common frequency and having a phase offset between them, and to mix said reference signals in variable proportions according to the value of input weighting signals to generate an output signal; comparing means arranged to compare the phase of said output signal with that of said input signal to determine whether said signals are in said desired phase relationship and, if not, to output one or more control signals indicative of the required adjustment in the phase of said output signal to achieve said desired phase relationship; and an adjustable ring oscillator comprising a plurality of stages connected in a ring and arranged to propagate oscillations around said ring, said ring oscillator being responsive to said one or more control signals to propagate said oscillations in first and second directions around said ring and being arranged to provide said weighting signals to said mixing means from outputs of ones of its stages.