- 专利标题: Apparatus and methods for digital fractional phase locked loop with a current mode low pass filter
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申请号: US17101665申请日: 2020-11-23
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公开(公告)号: US11218155B2公开(公告)日: 2022-01-04
- 发明人: Tingjun Wen , Sadok Aouini , Naim Ben-Hamida , Mahdi Parvizi , Matthew Mikkelsen
- 申请人: Ciena Corporation
- 申请人地址: US MD Hanover
- 专利权人: Ciena Corporation
- 当前专利权人: Ciena Corporation
- 当前专利权人地址: US MD Hanover
- 代理机构: Young Basile Hanlon & MacFarlane, P.C.
- 主分类号: H03L7/06
- IPC分类号: H03L7/06 ; H03L7/197 ; H03L7/087 ; H03L7/107 ; H03L7/093 ; H03L7/099
摘要:
Described is a digital fractional phase locked loop (DFPLL) with a current mode low pass filter. The DFPLL includes a binary phase frequency detector (BPFD) configured to output a directional pulse based on comparison of a reference clock and a feedback clock, a current mode low pass filter connected to the BPFD, and a current controlled oscillator (CCO) connected to the current mode low pass filter. The current mode low pass filter configured to output a control current based on at least the directional pulse when a current steering switch directly controlled by the directional pulse switches to the CCO. The CCO configured to adjust a frequency of the CCO based on the control current to generate an output clock. The feedback clock based on the output clock and the reference clock aligned with the feedback clock by adjusting the frequency of the output clock until frequency and phase lock.
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