| 摘要 |
PURPOSE: A frequency synthesizer for wireless terminal is provided to detect a phase of a signal by using a digital signal processor in the frequency synthesizer and improve a characteristic of lock time by removing a loop filter. CONSTITUTION: A digital/analog converter(21) is used for converting digital information to an analog signal. A voltage control oscillator(22) generates voltage according to the converted analog signal and a signal with a predetermined frequency. A frequency counter(23) displays the frequency of the signal of the voltage control oscillator(22) and feeds back the signal. A digital signal processor(24) performs a frequency converting process for the frequency of an internal signal with the frequency of the signal applied from the frequency counter(23), detects phase information according to the converted frequency value, and outputs the detected phase information to the digital/analog converter(21).
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