Phase frequency detector used in phase locked loop
AssigneeRealtek Semiconductor Corp.
InventorsYu-Pin Chou, Yi-Shu Chang
Life of this patent
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Abstract
A phase frequency detector used in a phase locked loop includes a phase error detecting unit for outputting phase error signals according to a phase error between a first input signal and a second input signal, and a reset unit coupled to the phase error detecting unit. The reset unit outputs reset signals according to the first and second input signals so as to reset the phase error detecting unit without delay time. Thus, it is possible to make the output timing of the phase error signal in a more precisely linear proportion to the phase error value and to enhance the sensitivity of the phase locked loop.
Claims13
A phase frequency detector comprising:
- a phase error detecting unit for outputting at least a phase error signal according to a phase error between a first input signal and a second input signal;
- and
- a reset unit coupled to the phase error detecting unit for receiving the first input signal and the second input signal, and for outputting a reset signal according to the first input signal and the second input signal, in order to reset the phase error detecting unit.
A phase locked loop comprising:
- a phase error detector for receiving a first input signal and a second input signal, and outputting a phase error signal;
- and
- a clock signal generator for outputting the second input signal according to the phase error signal;
- wherein the phase error detector comprises:
- a phase error detecting unit for outputting the phase error signal according to a phase error between the first input signal and the second input signal;
- and
- a reset unit coupled to the phase error detecting unit for receiving the first input signal and the second input signal, and for outputting a reset signal according to the first input signal and the second input signal, in order to reset the phase error detecting unit.
Dependencies are inferred from the claim text.