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    Carrier-recovery loop with stored initialization in a radio receiver
    2.
    发明授权
    Carrier-recovery loop with stored initialization in a radio receiver 失效
    在无线电接收机中存储初始化的载波恢复循环

    公开(公告)号：US6072842A

    公开(公告)日：2000-06-06

    申请号：US968029

    申请日：1997-11-12

    申请人： Stephen T. Janesch ,  Paul G. Schnizlein ,  Ed Bell

    发明人： Stephen T. Janesch ,  Paul G. Schnizlein ,  Ed Bell

    IPC分类号： H03L7/093 ,  H03L7/099 ,  H03L7/14 ,  H04L1/24 ,  H04L7/033 ,  H04L27/00 ,  H04L27/22 ,  H04L27/227 ,  H03D3/24

    CPC分类号： H04L27/22 ,  H03L7/0991 ,  H03L7/146 ,  H04L1/24 ,  H04L27/2273 ,  H03L7/093 ,  H04L2027/0028 ,  H04L2027/0046 ,  H04L2027/0067 ,  H04L2027/0069 ,  H04L7/0334

    摘要： A carrier-recovery loop for a receiver in a communication system with features that facilitate initialization of the loop. The carrier-recovery loop is a PLL that uses a feedback signal to keep a recovery oscillator phase-locked to the carrier of a received signal. In the present invention, an initializing value of the feedback signal is stored in a memory and provided to a digitally controlled recovery oscillator (DCO). This initializing value brings the recovered signal to an initial frequency that approximates the carrier frequency. When the receivers starts to acquire a phase-lock with the carrier, the carrier-recovery loop is in a condition close to the desired phase lock. Preparing the DCO in this manner imparts a significant improvement to the carrier-recovery loop. The response time for the loop to acquire a phase lock depends in part on its initial frequency offset from the carrier. In general, reducing this initial offset reduces the loop's acquisition time. By thus anticipating the frequency of the carrier, this carrier-recovery loop can have an improved acquisition time to reach phase lock. The initializing value of the feedback signal can be generated by recording a sample of the feedback signal when the carrier-recovery loop is phase-locked to a received signal or to an on-board crystal oscillator. The invention also includes a mechanism to correct drifts in the crystal oscillator's frequency.

    摘要翻译： 具有促进循环初始化的特征的通信系统中的接收机的载波恢复回路。 载波恢复环路是使用反馈信号将恢复振荡器锁相到接收信号的载波的PLL。 在本发明中，将反馈信号的初始化值存储在存储器中并提供给数字控制的恢复振荡器（DCO）。 该初始化值使恢复的信号达到近似载波频率的初始频率。 当接收机开始与载波采集相位锁定时，载波恢复环路处于接近所需相位锁定状态。 以这种方式准备DCO对载体恢复循环有显着的改进。 环路获取锁相的响应时间部分取决于其与载波的初始频率偏移。 一般来说，减少初始偏移可以减少环路的采集时间。 通过这样预期载波的频率，该载波恢复回路可以具有改善的采集时间以达到锁相。 反馈信号的初始化值可以通过当载波恢复环路锁相到接收信号时记录反馈信号的样本，或者通过在板上晶体振荡器上记录反馈信号的初始化值。 本发明还包括校正晶体振荡器频率漂移的机制。