Patent ID: 8289087
Filing Date: 2012-10-16
Classification: H03M

Abstract:
1. A computer-implemented method for detecting a phase shift between an I data clock and a Q data clock in processing an I data signal or a Q data signal used in quadrature modulation or quadrature demodulation, wherein said I data clock and said Q data clock are obtained based on a sampling clock, and said method comprising: receiving an input of said I data clock and said Q data clock; performing exclusive-ORing (XORing) on said I data clock and said Q data clock; latching a result of the performance of XORing on a phase sampling clock which is asynchronous with said I data clock and said Q data clock to create a sampled result; incrementing a first number when said sampled result having a value of 0 occurs in a predetermined period of time; incrementing a second number when said sampled result having a value of 1 occurs in said predetermined period of time; comparing said incremented first number and incremented second number and determining, based on a phase determination criterion, a phase shift between said I data clock and said Q data clock; detecting a phase shift between said I data clock and said Q data clock according to said determination based on said phase determination criterion; delaying said I data clock or said Q data clock; incrementing said first number and said second number if said step of delaying said I data clock or Q data clock is executed or incrementing a third number when said sampled result of 0 occurs and incrementing a fourth number when said result of 1 occurs, if said step of delaying said I data clock or said Q data clock is not executed; and determining a phase shift by comparing said first number, said second number, said third number, and said fourth number and distinguishing between a case where said I data clock and said Q data clock are out of phase with each other by 90° and a case where said I data clock and said Q data clock are out of phase with each other by 270°.