CN1859005A - Clock back-up system in communication device - Google Patents
Clock back-up system in communication device Download PDFInfo
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- CN1859005A CN1859005A CN 200510111110 CN200510111110A CN1859005A CN 1859005 A CN1859005 A CN 1859005A CN 200510111110 CN200510111110 CN 200510111110 CN 200510111110 A CN200510111110 A CN 200510111110A CN 1859005 A CN1859005 A CN 1859005A
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Abstract
This invention discloses a clock bachup system in a communication device to reduce the cost for clock backup of the base stations on the basis of meeting the reliability of clocks, which takes TCVCXO as the standby clock of a communication device (base station), the primary and standby clocks are designed in two phase locking loops of a same signle board to carry out the switch by locking the loops and the reference source and clock test.
Description
Technical field
The present invention relates to mobile communication technology, particularly the clock backup technology in the mobile communications network.
Background technology
Over nearly 20 years, the development of mobile communication technology experienced for two generations, having finished from the analog cellular communication technology of the first generation is the transition of the digital communication technology of representative to the second generation with global system for mobile communications (Global System for MobileCommunications is called for short " GSM ").Now to 3-G (Generation Three mobile communication system) (Third Generation Mobile Communications System is called for short " 3G ") development.
In the development communication technologies process, the reliability to the work clock of base station in the communication system constantly proposes higher requirement.Usually adopt the mode of the active and standby clock board of configuration to improve reliability at present.Simultaneously, the clock accuracy of considering the base station requires very high, and general primary and backup clock all adopts rubidium clock or high-grade constant-temperature crystal oscillator (Oven Controlled Crystal Oscillator is called for short " OCXO ").
In actual applications, there is following problem in such scheme: the price of rubidium clock and OCXO is very high, causes communication system clock backup cost too high.
Summary of the invention
In view of this, main purpose of the present invention is to provide the clock back-up system in a kind of communication equipment, makes under the prerequisite that satisfies the reliability of clock requirement, reduces the base station clock backup cost.
For achieving the above object, the invention provides the clock back-up system in a kind of communication equipment, comprise active clock and standby clock, described standby clock adopts temperature-compensated voltage-controlled crystal oscillator to realize.
Wherein, described active clock and standby clock comprise a clock detection and select module and first, second phase-locked loop on same veneer in this veneer, wherein,
Comprise described active clock in first phase-locked loop, this first phase-locked loop is used for this active clock and reference clock source locking;
Comprise described standby clock in second phase-locked loop, this second phase-locked loop is used for this standby clock and the locking of described reference clock source;
Whether described clock detection selects module to be used to detect described active clock working properly, if undesired then switch to described standby clock.
In this external described system, described phase-locked loop can adopt software or hardware phase-lock mode.
In this external described system, described reference source can be one of following:
Global positioning system, E1 clock or building integrated timing supply.
In this external described system, described clock detection selects module also to be used for report and alarm information when described active clock work is undesired.
In this external described system, described active clock and standby clock in two veneers, switch to the veneer at standby clock place respectively when active clock work is undesired.
In this external described system, described active clock can use one of following device to realize:
Constant-temperature crystal oscillator, rubidium clock or caesium clock.
In this external described system, described communication equipment can be the base station in the mobile communications network.
By relatively finding, the main distinction of technical scheme of the present invention and prior art is, with the standby clock of temperature-compensated voltage-controlled crystal oscillator (Temperature Compensated Voltage ControlledCrystal Oscillator is called for short " TCVCXO ") as communication equipment (as the base station).
Primary, spare clock design by two phase-locked loops and reference source locking, selects to carry out active and standby switching by clock detection in two phase-locked loops of same veneer.
Difference on this technical scheme has brought comparatively significantly beneficial effect, has promptly reduced cost.With respect to the prior art of using high-grade clock, the cost of the TCVCXO that the present invention uses is about 1/5th of OCXO, compares with rubidium clock, caesium clock that then cost is lower, so can reduce the system clock backup cost effectively.
In addition, simplified configuration.Because in a veneer, so need only the backup that a veneer just can be realized system clock, with respect to the mode of using two veneers in the prior art, configuration obtains simplifying with primary, spare clock design in the present invention.
We can say that the present invention has not only overcome at present because TCVCXO stability adopts its technology prejudice as system clock inadequately and not, and can satisfy the reliability of clock requirement of base station system.Specifically, it is because the stability of TCVCXO is good inadequately as the main cause of system clock that prior art does not adopt TCVCXO, if the error that the occurrence temperature sudden change has above communication standard produces.But, it is considered herein that TCVCXO is enough to competent standby clock.This be because, the precision of TCVCXO when operate as normal can meet the demands in fact, and system generally had been in steady-working state when active and standby switching took place, and temperature is also stable already, the situation of little temperature jump is so TCVCXO can meet the demands at this moment.In addition, system's most of the time also is to use active clock, and the chance that standby clock uses is few, the time short, so it is just littler to run into the probability of temperature jump.
Description of drawings
Fig. 1 is the structural representation of clock back-up system in the communication equipment in accordance with the principles of the present invention.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing.
Generally speaking, the principle of clock back-up system of the present invention is, adopt temperature-compensated voltage-controlled crystal oscillator (Temperature Compensated Voltage Controlled Crystal Oscillator, be called for short " TCVCXO ") replace OCXO as standby clock, satisfying the base station system reliability requirement simultaneously, the cost of standby clock is being reduced to about 1/5th when adopting OCXO, and, can adopt the scheme of single configurable clock generator plate among the present invention, simplify configuration.
Proposing the present invention's general concept before thinks, though the precision of TCVCXO can satisfy the reliability requirement of backup clock, but, vibration frequency changes owing to can varying with temperature, therefore stability is not so good, if the sudden change of occurrence temperature, the error that can cause surpassing communication standard produces, and is not suitable for being applied in the clock back-up system of communication equipment.
But the present inventor draws the standby clock that different conclusions: TCVCXO can be used as clock back-up system fully by research.Reason is that when the master/backup clock switching took place, system generally had been in steady-working state, and temperature is also stable already, and the situation of little temperature jump is so TCVCXO can meet the demands at this moment.In addition, system's most of the time also is to use active clock, and is few by the chance of using with clock, and the time is short, so the probability that runs into temperature jump just still less.Simultaneously, the cost of TCVCXO is compared with the cost of OCXO greatly and is reduced, and very helps reducing the cost of clock back-up system.
Below with reference to Fig. 1, describe according to the clock back-up system in the communication equipment of the first embodiment of the present invention, wherein, communication equipment is the base station in the mobile communications network.
As shown in the figure, clock back-up system comprises: as the OCXO of active clock, as standby clock TCVCXO, the first and second software phase discriminators, first and second filtering and control phase-locked algoritic module, first and second digital to analog converters, clock detection and select module.
Wherein, the first software phase discriminator, first filtering and control phase-locked algoritic module, first digital to analog converter and OCXO and connect have successively constituted first phase-locked loop, and it is used for OCXO and reference clock source locking.
The second software phase discriminator, second filtering and control phase-locked algoritic module, second digital to analog converter and TCVCXO and connect successively constitute second phase-locked loop, and it is used for TCVCXO and reference clock locking.
Whether clock detection selects module to be used to the OCXO that detects as active clock working properly, if undesired then switch to standby clock TCVCXO, report and alarm information simultaneously for example, reports and is used to start to control the veneer of making usefulness in the communication equipment.And first and second phase-locked loops output to clock detection and select module.
In the present embodiment, first and second phase-locked loops and clock detection select module all to be arranged on the same veneer.
Following brief description OCXO and TCVCXO.
The frequency of oscillation of quartz crystal can change with variation of temperature, can make a frequency to the variation of temperature curve, and the slope of this change curve is different under different temperature.A heater is arranged among the OCXO, make the temperature of quartz crystal remain on one more among a small circle by negative feedback mechanism, and frequency of oscillation is to temperature-insensitive in this scope, change curve is more smooth in other words.A temperature sensor is arranged among the TCVCXO, can set different control voltage according to different temperature and carry out frequency compensation.It is lower that TCVCXO and OCXO compare cost.
It is pointed out that except OCXO in according to other embodiments of the invention, active clock also can be realized by constant-temperature crystal oscillator, rubidium clock or caesium clock.
The input of first and second phase-locked loops all is a reference source, in the present invention, reference source can be one of following: global positioning system (Global Position System, abbreviation " GPS "), E1 clock or building integrated timing supply (Building Integrated Timing Supply system is called for short " BITS ").
In the present embodiment, first and second phase-locked loops adopt the software phase-lock mode to realize.Persons of ordinary skill in the art may appreciate that in other embodiments first and second phase-locked loops also can adopt the hardware phase-lock mode to realize.PHASE-LOCKED LOOP PLL TECHNIQUE is the known prior aries of those of ordinary skills, does not do at this and gives unnecessary details.
More than the clock back-up system of present embodiment constituted be illustrated, the dynamic duty process of this clock back-up system is described below.
When communication device initiated, first and second phase-locked loops phase-locked by to reference source calibrated primary and backup clock.When operate as normal, it is normal from the OCXO of first phase-locked loop that clock detection selects module to judge, and the active clock signal is exported as the base station reference clock.If active clock breaks down, clock detection selects module to detect the active clock abnormal signal, at this moment,, then standby clock signal is exported as the base station reference clock if normal from the TCVCXO signal of second phase-locked loop, and report and alarm information.
In clock back-up system according to a second embodiment of the present invention, as first phase-locked loop at the OCXO place of active clock and as second phase-locked loop at the TCVCXO place of standby clock respectively in two veneers, when OCXO works when undesired, switch to the veneer at TCVCXO place.Its operation principle is similar with first embodiment, does not do at this and gives unnecessary details.
This shows that the present invention has reduced the base station clock backup cost when the reliability of clock that satisfies base station system requires.
Though by with reference to some preferred embodiment of the present invention, the present invention is illustrated and describes, those of ordinary skill in the art should be understood that and can do various changes to it in the form and details, and without departing from the spirit and scope of the present invention.
Claims (8)
1. the clock back-up system in the communication equipment comprises active clock and standby clock,
It is characterized in that described standby clock adopts temperature-compensated voltage-controlled crystal oscillator to realize.
2. the clock back-up system in the communication equipment according to claim 1 is characterized in that, described active clock and standby clock comprise a clock detection and select module and first, second phase-locked loop on same veneer in this veneer, wherein,
Comprise described active clock in first phase-locked loop, this first phase-locked loop is used for this active clock and reference clock source locking;
Comprise described standby clock in second phase-locked loop, this second phase-locked loop is used for this standby clock and the locking of described reference clock source;
Whether described clock detection selects module to be used to detect described active clock working properly, if undesired then switch to described standby clock.
3. the clock back-up system in the communication equipment according to claim 2 is characterized in that, described phase-locked loop can adopt software or hardware phase-lock mode.
4. the clock back-up system in the communication equipment according to claim 2 is characterized in that, described reference source can be one of following:
Global positioning system, E1 clock or building integrated timing supply.
5. the clock back-up system in the communication equipment according to claim 2 is characterized in that, described clock detection selects module also to be used for report and alarm information when described active clock work is undesired.
6. the clock back-up system in the communication equipment according to claim 1 is characterized in that, described active clock and standby clock in two veneers, switch to the veneer at standby clock place respectively when active clock work is undesired.
7. according to the clock back-up system in each described communication equipment in the claim 1 to 6, it is characterized in that described active clock can use one of following device to realize:
Constant-temperature crystal oscillator, rubidium clock or caesium clock.
8. the clock back-up system in the communication equipment according to claim 7 is characterized in that, described communication equipment can be the base station in the mobile communications network.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510111110 CN1859005A (en) | 2005-12-02 | 2005-12-02 | Clock back-up system in communication device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 200510111110 CN1859005A (en) | 2005-12-02 | 2005-12-02 | Clock back-up system in communication device |
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| CN1859005A true CN1859005A (en) | 2006-11-08 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101840357A (en) * | 2010-04-08 | 2010-09-22 | 北京星网锐捷网络技术有限公司 | Clock backup method and clock backup device |
| CN103414468A (en) * | 2013-06-25 | 2013-11-27 | 广州思信电子科技有限公司 | Phase-locked loop system |
| CN110988931A (en) * | 2019-10-31 | 2020-04-10 | 北京遥测技术研究所 | Clock self-checking circuit based on AD8310 detector |
-
2005
- 2005-12-02 CN CN 200510111110 patent/CN1859005A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101840357A (en) * | 2010-04-08 | 2010-09-22 | 北京星网锐捷网络技术有限公司 | Clock backup method and clock backup device |
| CN101840357B (en) * | 2010-04-08 | 2012-09-05 | 北京星网锐捷网络技术有限公司 | Clock backup method and clock backup device |
| CN103414468A (en) * | 2013-06-25 | 2013-11-27 | 广州思信电子科技有限公司 | Phase-locked loop system |
| CN103414468B (en) * | 2013-06-25 | 2016-08-31 | 广州思信电子科技有限公司 | Phase-locked loop systems |
| CN110988931A (en) * | 2019-10-31 | 2020-04-10 | 北京遥测技术研究所 | Clock self-checking circuit based on AD8310 detector |
| CN110988931B (en) * | 2019-10-31 | 2022-03-04 | 北京遥测技术研究所 | Clock self-checking circuit based on AD8310 detector |
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