Patent ID: 6980134
Filing Date: 2005-12-27
Classification: G01D,G06F,H02P,H03M

Abstract:
1. An apparatus for processing a plurality of input signals each of which vary sinusoidally with the value of a variable and out of phase with respect to each other, the apparatus comprising: a multiplier operable to multiply each of said signals with a respective one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase; a first combiner operable to combine the signals from said multiplying means to provide an output signal; wherein said predetermined phases of said periodic time varying signals are determined so that the output signal from said first combiner contains a single periodic component having said predetermined period whose phase varies with said variable; first processing circuitry operable to process said output signal from said first combiner to generate an output signal having a value which monotonically varies with the phase of the output signal from said first combiner and hence with the value of said variable over one period of said sinusoidal variation; second processing circuitry operable to process a periodic time varying signal having said predetermined period to generate an output signal having a value which monotonically varies with the phase of the periodic time varying signal processed; and a second combiner operable to combine the output signal value from said first processing circuitry with the output signal value from said second processing circuitry to provide a combined output signal having a value which monotonically varies with the value of said variable over one period of said sinusoidal variation.