Frequency synthesizer including a digital lock detector
AssigneeElectronics and Telecommunications Resarch Instittute
InventorsJa Yol Lee, Seong Do Kim, Mun Yang Park, Cheon Soo Kim, Hyun Kyu Yu
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Abstract
There is provided a digital lock detector and a frequency synthesizer using the same. The digital lock detector includes a comparator unit receiving a plurality of control bits, and generating a bit signal to notice a lock condition of the plurality of control bits; a delay cell block generating a plurality of delay signals based on the bit signal, and outputting a clock signal by combining the bit signal and the plurality of delay signals; and a detection unit detecting a shift time of the clock signal, and generating a lock indication signal according to the detection result.
Claims7
A frequency synthesizer including:
- a digital control oscillator adjusting a frequency of an output signal according to a plurality of control bits;
- a phase detector feeding back the output signal of the digital control oscillator and outputting an error signal;
- a digital loop filter generating the plurality of control bits from the error signal;
- and
- a digital lock detector receiving the plurality of control bits, and generating a lock indication signal to notice whether the output signal is locked to a target frequency or not.
Dependencies are inferred from the claim text.