Patent ID: 8022782
Filing Date: 2011-09-20
Classification: H03C

Abstract:
1. A two-point phase modulator, comprising: an input unit configured to output a division control signal based on a channel frequency signal and modulation data; a phase-locked loop (PLL) circuit configured to form a loop during an activation period of a loop control signal, detect a difference in phase between a reference frequency signal and a divided output frequency signal, store a voltage corresponding to the difference in phase, output an output frequency signal, change a frequency of the output frequency signal based on the stored voltage and a modulation signal, and generate the divided output frequency signal by dividing the output frequency signal based on the division control signal; a modulation signal generator configured to convert the modulation data from digital to analog based on a conversion gain value and output the modulation signal; and a conversion gain calibration unit configured to output the conversion gain value based on the output frequency signal and the reference frequency signal during a deactivation period of the loop control signal, wherein the conversion gain calibration unit includes, a frequency-digital converter configured to output digital output data based on the reference frequency signal and the output frequency signal during the deactivation period of the loop control signal, and a gain calibrator configured to calculate and output the conversion gain value using the output data and the modulation signal during the deactivation period of the loop control signal.