摘要:
A synthesizer (100) is used for generating a plurality of synthesized clock signals (128, 156). The synthesizer includes a clock source (102) for generating a common frequency reference signal (103), and a clock generator (104) coupled to the common frequency reference signal for generating a plurality of generated clock signals (106, 108), wherein each of the plurality of generated clock signals is offset from each other by a predetermined phase offset (189, 192). In addition, the synthesizer includes a plurality of PLLs (Phase Locked Loops) (166-168) for generating a selected one of the plurality of synthesized clock signals, wherein each of the plurality of PLLs is coupled to, and operates from, a corresponding one of the plurality of generated clock signals, and wherein the predetermined phase offset between each of the plurality of generated clock signals is known to suppress noise between the plurality of PLLs operating therefrom.
摘要:
A phase-frequency detector (110) includes an output stage (300) and a control stage (200). The output stage includes a pump up switched current source (350), a pump down switched current sink (360), and a constant current source (325) that are coupled to a charge pump output node (111). The control stage generates, in response to a divided variable frequency signal (FV) (136) and a reference frequency signal (FR) (106), a pump up control signal (246) and a pump down control signal (216).