Patent ID: 6566941
Filing Date: 2003-05-20
Classification: H04L

Abstract:
A phase detection device used in a phase demodulator with a certain phase resolution to calculate a phase using an in-phase signal and a quadrature signal generated by the phase demodulator, which phase detection device comprises:a quadrant determining module, which receives the in-phase signal and the quadrature signal, uses the highest bits of the in-phase signal and the quadrature signal to determine which quadrant the signals belong to, generates a first phase approximate value according to the determined quadrant, and outputs the absolute values of the in-phase signal and the quadrature signal; a first comparison module, which receives the absolute values of the in-phase signal and the quadrature signal output from the quadrant determining module, generates a second phase approximate value according to the relative magnitudes of the absolute values of the in-phase signal and the quadrature signal, and takes the one with a larger absolute value as a first coordinate component and the one with a smaller absolute value as a second coordinate component for further output; a second comparison module, which receives the first and second coordinate components and takes the ratio of them with the larger component as the divisor to obtain a coordinate ratio, which is used to generate a third phase approximate value and a rotation angle; a coordinate transforming module, which receives the first and second coordinate components and the rotation angle output from the second comparison module, converts the coordinate components into a third coordinate component and a fourth coordinate component using a set of specific functions, and outputs the third and fourth coordinate components to the second comparison module; and a phase computing module, which receives the first phase approximate value, the second phase approximate value, and the third phase approximate value, and uses the second phase approximate value to calculate a total phase of the in-phase signal and the quadrature signal.