| 摘要 |
PURPOSE: A clock phase change history managing unit of a network synchronous apparatus is provided to manage a history of a clock by checking a variation of the clock output during a predetermined time. CONSTITUTION: A clock phase change history managing unit comprises an internal clock part(12a) and a network synchronous unit control part(20a). The internal clock part(12a) consists of first to third buffers(110a,110b,110c) each of which is to store a phase change history of an output clock. In the first buffer(110a) is stored a phase of a clock output from the internal clock part(12a) by an unit of a first set time. In the second buffer(110b) is stored a phase of a clock output from the internal clock part(12a) by an unit of a second set time. In the third buffer(110c) is stored a phase of a clock output from the internal clock part(12a) by an unit of a third set time. The network synchronous unit control part(20a) consists of first to third tacks(120a-120c), a backup task(121), an output task, and first to third memories(130a,130b,130c). The first task(120a) reads the contents of the first buffer(110a) by the unit of the first set time to store the first memory(130a), the second task(120b) reads the contents of the second buffer(110a) by the unit of the second set time to store the second memory(130b), and the third task(120c) reads the contents of the third buffer(110c) by the unit of the third set time to store the third memory(130c). The backup task(121) backups data of each memory(130a-130c) to another network synchronous unit control part of a standby mode. The output task(122) receives data from the first to third memories(130a-130c), and analyzes a received command of a manager.
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