发明授权
US4970475A Linearized three state phase detector 失效
线性三态相位检测器

  • 专利标题: Linearized three state phase detector
  • 专利标题(中): 线性三态相位检测器
  • 申请号: US500626
    申请日: 1990-03-28
  • 公开(公告)号: US4970475A
    公开(公告)日: 1990-11-13
  • 发明人: Steven F. Gillig
  • 申请人: Steven F. Gillig
  • 申请人地址: IL Schaumburg
  • 专利权人: Motorola Inc.
  • 当前专利权人: Motorola Inc.
  • 当前专利权人地址: IL Schaumburg
  • 主分类号: H03D13/00
  • IPC分类号: H03D13/00 H03L7/089
Linearized three state phase detector
摘要:
A linearized three state phase detector (300) that exhibits a linear transfer function of phase to current or charge at and around the zero phase error region. The inputs to the D flip-flops (301 and 302) are tied to a logic high. the first flip-flop (301) is clocked with reference signal F.sub.r while the other flip-flop (302) is clocked with a variable frequency feedback signal F.sub.v. F.sub.v is typically from a voltage controlled oscillator in a phase locked loop. The outputs of the flip-flops are ANDed together with the result of this operation going through a delay element (304) before reseting one of the flip-flops (301). The other flip-flop (302) is reset by the output of the AND gate (304) without the delay element (304). Each flip-flop output enables a charge pump--one negative polarity (306) and one positive polarity (305). The present invention will maintain a lock condition in a phase locked loop by extending the DOWN pulse enabling the negative polarity charge pump (306) to the same width as the UP pulse that enables the positive pump (305). This will create a net zero charge from the present invention.
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