KR960009775A - Standard clock selection device and control method of local exchange - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an apparatus and method for supplying a reference clock to a clock synchronizing apparatus of a local exchange.

2. The technical problem to be solved by the invention

In the conventional local exchange, when the reference clock applied from the upper station is not provided, the reference clock provided inside the clock synchronizing device solves the instability of the exchange system caused by the inferior frequency performance and stability.

3. Summary of Solution to Invention

First, in the present invention, when a frequency signal of GHz unit propagated from a satellite is received by a global positioning system (GPS), the clock generator 10 generates a standard clock in synchronization with it. If the reference clock is not received from the upper station, the logic operation unit 18 and the CPU 16 perform predetermined control to provide the clock synchronization unit 28 with the standard clock generated by the clock generation unit 10. .

4. Important uses of the invention

It is used in the clock synchronization device of the local exchange which requires the reference clock.

※ Selection first degree.

Description

Standard clock selection device and control method of local exchange

Since this is an open matter, no full text was included.

1 is a view showing a reference clock selection device according to the present invention.

Claims (7)

An apparatus for supplying a clock to a clock synchronizing device of an exchange system, comprising: first clock receiving means for receiving a first reference clock applied from a higher station, and a second reference clock for receiving a second reference clock from an external device generating a predetermined clock; One clock receiving means, monitoring means for monitoring an error state of the first reference clock and the second reference clock, and control means for controlling to select a reference clock in a steady state by monitoring the monitoring means. Reference clock selector that supplies a clock to the clock synchronizer. 2. The first apparatus of claim 1, wherein the first clock signal is connected between the first clock receiving means and the clock synchronizing device and selects and outputs the first reference clock of the first clock means to the clock synchronizing device under control of the control means. Second selection means connected between a selection means, the second clock receiving means and the clock synchronization device, and selecting and outputting a second reference clock of the second clock means to the clock synchronization device under the control of the control means; Reference clock selection device characterized in that it further comprises. 3. The apparatus according to claim 1 or 2, wherein the external device is a satellite frequency receiving means for receiving a predetermined frequency from a communication satellite and a clock generating means for generating the second reference clock in synchronization with the frequency of the satellite frequency receiving means. Reference clock selection device characterized in that the configuration. 4. The reference clock selection device according to claim 3, wherein the first clock receiving means and the second clock receiving means have one or more input / output lines for transmitting and receiving the first and second reference clocks. The method of claim 4, wherein the monitoring means comprises: a first monitoring unit for monitoring an error state of the first reference block of each output line of the first clock receiving unit, and an error state of the second reference clock of the second clock receiving unit; A reference clock selection device comprising a second monitoring unit for monitoring. 6. The control unit as claimed in claim 5, wherein the control unit performs a logical operation on each output of the first monitoring unit and each output of the second monitoring unit, thereby operating the first selection unit and the second selection unit, and the first monitoring unit. And a line selection control unit for controlling the first selection means and the second selection means to detect the respective outputs and the respective outputs of the second monitoring unit and to select a line operating normally. A control method for supplying a clock to a clock synchronizing device of an exchange system, comprising: a plurality of external devices receiving first reference clocks respectively applied from a plurality of output lines of an upper station by a first clock receiving means and generating a predetermined frequency; A first process of receiving, by the second clock receiving means, second reference clocks respectively applied from an output line, a second process of monitoring an error state of the first reference clock and the second reference clocks, and in the second process A third step of selecting a normal reference clock of the first clock receiving means and providing the clock synchronization device to the clock synchronizing device when at least one of the first reference clocks detects a normal state; When all of the first reference clocks are in an abnormal state, a fourth process of selecting a normal reference clock of the second clock receiving means and providing the clock to the clock synchronizing apparatus is performed. A control method. ※ Note: The disclosure is based on the initial application.