Systems and methods for generating clock phase signals with accurate timing relations are disclosed. For example, four clock signals spaced by 90 degrees can be generating from differential CML clock signals. A CML to CMOS converter converts the differential CML clock signals to differential CMOS clock signals and provides duty cycle correction. Delay cells produce delayed clock signals from the differential CMOS clock signals. The differential CMOS clock signals and the delayed clock signals are logically combined to produce four quarter clock signals having active times of one-quarter clock period. Set-reset latches produce the four clock signals from the quarter clock signals. A calibration module control delays of the delay cells and controls the duty cycle correction of the CML to CMOS converter to adjust the timing relationships of the four clock signals. The four clock signals may be used, for example, in a deserializer.