公开(公告)号：US06791906B1

公开(公告)日：2004-09-14

申请号：US10699546

申请日：2003-10-30

申请人： Timothy C. Fischer ,  Samuel D. Naffziger

发明人： Timothy C. Fischer ,  Samuel D. Naffziger

IPC分类号： G04C1500

CPC分类号： H03L7/16 ,  H03L7/087

摘要： In a preferred embodiment, the invention provides a method and system for allowing a frequency synthesizer to function despite long delays. A first and second phase comparator, each with at least three inputs and an output are preset to a predetermined logical value by a first control circuit. A first signal is connected to an input of the first and second phase comparators. A second signal is connected to a second input of the second phase comparator and to the input of a programmable dead zone delay circuit. The output of the programmable dead zone delay circuit is connected to a second input of the first phase comparator. A preset value, determined by the first control circuit, is presented on the outputs of the first and second phase comparators. Until metastability is resolved, these outputs retain a valid fail-safe default.

摘要翻译： 在优选实施例中，本发明提供一种即使长时间延迟也允许频率合成器起作用的方法和系统。 通过第一控制电路将具有至少三个输入和输出的第一和第二相位比较器预设为预定的逻辑值。 第一信号连接到第一和第二相位比较器的输入。 第二信号连接到第二相位比较器的第二输入端和可编程死区延迟电路的输入端。 可编程死区延迟电路的输出连接到第一相位比较器的第二输入端。 由第一控制电路确定的预设值呈现在第一和第二相位比较器的输出端上。 直到亚稳态解决，这些输出保留有效的故障安全默认值。

公开(公告)号：US06567346B2

公开(公告)日：2003-05-20

申请号：US09757074

申请日：2001-01-08

申请人： Thomas J. Aton ,  Shivaling S. Mahant-Shetti

发明人： Thomas J. Aton ,  Shivaling S. Mahant-Shetti

IPC分类号： G04C1500

CPC分类号： G04F5/16

摘要： An absolute time scale clock includes a radioactive isotope and a computer. The computer includes a processor that determines an indication of the current absolute time and a memory that stores a decay constant of the radioactive isotope, a reference time, and an amount of the isotope at the reference time. A energy supply that provides power to the computer. The absolute time scale clock further includes a detector positioned to respond to emissions from the radioactive isotope. The detector generates an indication of the number of emissions over a time interval that varies with the decay rate of the isotope. The processor is responsive to the indication from the detector, the decay constant, the reference time, and the reference amount to determine the indication of current absolute time.

公开(公告)号：US06249488B1

公开(公告)日：2001-06-19

申请号：US08790276

申请日：1997-01-28

申请人： Clark R. Williams ,  William J. Podkowa

发明人： Clark R. Williams ,  William J. Podkowa

IPC分类号： G04C1500

CPC分类号： G04G99/006 ,  G04G3/00 ,  G06F1/04 ,  G06F1/32

摘要： A low power timekeeping system utilizes a state machine to first read seconds stored in a RAM and update seconds and then determine if the minutes requires updating. If the minutes do not require updating then the sequencer stops operation until the next update cycle. Similarly, the minutes, hours, days of the week, date of the month, month, and year are updated only as needed in each update cycle thereby lowering the power requirement needed by the timekeeping system.

摘要翻译： 低功率计时系统利用状态机首先读取存储在RAM中的秒数，并更新秒数，然后确定分钟是否需要更新。 如果分钟不需要更新，则定序器将停止运行，直到下一个更新周期。 类似地，分钟，小时，星期几，月份，月份和年份的日期仅在每个更新周期中根据需要进行更新，从而降低计时系统所需的功率需求。