CN101202562A - Cable modem and gain adjustment method thereof - Google Patents
Cable modem and gain adjustment method thereof Download PDFInfo
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- CN101202562A CN101202562A CNA2007100740951A CN200710074095A CN101202562A CN 101202562 A CN101202562 A CN 101202562A CN A2007100740951 A CNA2007100740951 A CN A2007100740951A CN 200710074095 A CN200710074095 A CN 200710074095A CN 101202562 A CN101202562 A CN 101202562A
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Abstract
The invention is applicable to the field of network communication and provides a cable modem and a gain adjustment method thereof. The method includes the following steps of judging whether the current signal is a weak signal or not; reading the level value of the current frequency point when the signal is weak; and automatically adjusting the grain control grade according to the level value. The gain adjustment method for the cable modem of the embodiment of the invention judges whether the current signal is weak and when the signal is weak, the level value of the current frequency point is read and the gain adjustment grade is automatically adjusted according to the current level value, thus enlarging the acceptable level range.
Description
Technical field
The invention belongs to network communication field, relate in particular to a kind of cable modem and gain adjusting method thereof.
Background technology
Cable modem (Cable Modem) is a kind of device that can carry out the high-speed data access by cable TV network, and two interfaces are generally arranged, and one of them interface is connected with the cable TV port, and another interface is connected with computer.Cable modem receives and sends data on two different directions, the uplink and downlink digital signal is modulated on the television channel of some 6MHz of transmitted in both directions or 8MHz bandwidth with different modulation systems.
Cable modem comprises master chip and tuner.In the prior art, cable modem utilizes variable gain amplifier in the tuner, and (Variable Gain Amplifie, acquiescence controlling grade incoming level VGA) carry out frequency locking to radio-frequency current (RF) signal.Promptly utilize the acquiescence controlling grade of VGA interface in the tuner to receive-20dBmV～+ level range of 28dBmV (modulation system is 64QAM, and different cable modems have the difference of 1dBmV～2dBmV).Existing cable modem can't be adjusted the gain controlling grade, and receivable level range is restricted, and can't surf the Net when network condition is relatively poor relatively.
Summary of the invention
The purpose of the embodiment of the invention is to provide a kind of cable modem and gain adjusting method thereof, is intended to solve existing cable modem and can't adjusts the gain controlling grade, the problem that receivable level range is restricted.
The embodiment of the invention is achieved in that a kind of gain adjusting method of cable modem, said method comprising the steps of:
Judge whether current demand signal is weak signal;
When weak signal, read the level value of current frequency;
Automatically adjust the gain controlling grade according to described level value.
The present invention also provides a kind of cable modem, comprises master chip and tuner, and master chip comprises the QAM status register, and tuner comprises gain register, and described master chip also comprises strong and weak judge module of signal and level value judge module; Described tuner comprises that also the gain controlling grade is provided with module automatically, wherein,
The strong and weak judge module of described signal, the value that is used to read the WEAKSIG position of QAM status register judges whether current demand signal is weak signal;
Described level value judge module is used for judging current level value when weak signal;
Described gain controlling grade is provided with module automatically, is used for changing according to the judged result of described level value judge module the value of described gain register, and the gain controlling grade is set.
The gain adjusting method of the cable modem of the embodiment of the invention, by judging whether current demand signal is weak signal, when weak signal, read the level value of current frequency, adjust the gain controlling grade of tuner automatically, enlarged receivable level range according to level value.
Description of drawings
Fig. 1 is the gain adjusting method schematic diagram of the cable modem that provides of the embodiment of the invention.
Fig. 2 is a gain adjusting method flow chart in the line process on the cable modem that provides of the embodiment of the invention.
Fig. 3 is cable modem that the embodiment of the invention the provides back signal gain adjusting method flow chart when changing of reaching the standard grade.
Fig. 4 is the cable modem schematic diagram that the embodiment of the invention provides.
Fig. 5 is the cable modem schematic diagram that the another kind of embodiment of the present invention provides.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
The gain adjusting method of the cable modem of the embodiment of the invention, the strong and weak gain of adjusting cable modem automatically according to current demand signal has enlarged the receivable level range of cable modem.
Fig. 1 shows the realization flow of the cable modem gain adjusting method that the embodiment of the invention provides, and details are as follows:
Step S101: judge whether current demand signal is weak signal.
The master chip of cable modem comprises the QAM status register.In the QAM status register, that describes the QAM state mainly contains two, position 0 (WEAKSIG) and position 1 (QAMLOCK).Wherein, (whether Automatic Gain Control AGC) has reached its maximum gain to the control of WEAKSIG bit representation automatic gain, i.e. expression monitors the signal of low amplitude, or signal may be lost.The value of WEAKSIG position is 0, expression signal normal (or strong signal); The value of WEAKSIG position is 1, and the expression signal is a weak signal.Whether QAMLOCK bit representation cable modem locks (0-non-locking, 1-is locked).
Step S102:, read the level value of current frequency if current demand signal is a weak signal.
Step S103: according to the level value that reads the value of low two of gain register is carried out corresponding setting, adjust the VGA gain controlling grade of tuner automatically.
If current demand signal is weak signal, the level value of the current frequency that reads is less than 0 o'clock, illustrate that signal too a little less than, exceed the level range of current gain controlling grade, so improve the gain controlling grade.
If current demand signal is a weak signal, the level value of the current frequency that reads is not less than at 0 o'clock, illustrates that signal is too strong, exceeds the level range of current gain controlling grade, therefore reduces the gain controlling grade.
Handling process when the gain adjusting method of the cable modem of the embodiment of the invention is applicable to line process on the cable modem and the back signal of reaching the standard grade changes.
For convenience of description, the embodiment of the invention is an example with the MT2060 tuner, describes the specific implementation of the embodiment of the invention in detail.
The gain controlling of MT2060 tuner VGA is divided into Three Estate: MT2060 VGAG 0DB, MT2060_VGAG_5DB and MT2060_VGAG_11DB.The controlling grade that general acquiescence adopts is MT2060_VGAG_5DB.
Following table has provided the gain controlling grade of MT2060 tuner VGA of the value correspondence of low two of gain register.
| The value that register is low two | Explanation is selected in gain |
| 00 | MT2060_VGAG_0DB |
| 01 | MT2060_VGAG_5DB |
| 10 | Keep |
| 11 | MT2060_VGAG_11DB |
In the line process, as shown in Figure 2, the gain adjusting method of cable modem is as follows on cable modem:
In step S201, the hardware to its inside after cable modem starts carries out initialization.
In step S202, the value that gain register is low two is set to 01, selects the gain controlling grade of acquiescence.The gain controlling grade that general acquiescence adopts is MT2060_VGAG_5DB.
In step S203, obtain the frequency of current scanning.
In step S204, read the value of WEAKSIG position in the QAM status register, judge whether current demand signal is weak signal.
If current demand signal is a weak signal, then change step S205 over to;
If current demand signal is not a weak signal, then change step S208 over to.
In step S205, read the level value of current frequency, whether the decision level value is less than 0.If the level value of current frequency illustrates that less than 0 signal is too low, changes step S206 over to; If the level value of current frequency is not less than 0, illustrate that signal is too high, changes step S207 over to.
In step S206, improve the gain controlling grade, low two of tuner gain register are set to 11, select gain controlling grade MT2060_VGAG_11DB, change step S208 over to.
In step S207, reduce the gain controlling grade, low two of the gain register of tuner are set to 00, select gain controlling grade MT2060_VGAG_0DB, change step S208 over to.
In step S208, the DL synchronization passage.
In step S209, read the value of QAM status register QAMLOCK position, judge whether down going channel is synchronous.
The value of QAM status register QAMLOCK position is that explanation in 1 o'clock is synchronous, and the value of QAMLOCK position is that explanation in 0 o'clock is not synchronous.
If down going channel is synchronous, change step S210 over to;
If down going channel is not synchronous, low two of tuner gain register are set to 01, select the gain controlling grade MT2060_VGAG_5DB of acquiescence; Scan next frequency, change step S204 over to;
In step S210, the locking down going channel.
In step S211, obtain the data feedback channel parameter, the locking data feedback channel;
In step S212, set up IP and connect.
In step S213, download configuration file is reached the standard grade after the registration.
On the cable modem in the line process, when the DL synchronization signal, judge current network signal by the value that reads WEAKSIG position in the QAM status register, adjust the gain controlling grade of tuner according to the real network signal dynamics, enlarged the receivable level range of cable modem, thereby cable modem is reached the standard grade under more loose network environment.
When signal changed after cable modem was reached the standard grade, as shown in Figure 3, its gain adjusting method was as follows:
In step S301, read the value of QAM status register WEAKSIG position.
In step S302, judge according to the value of QAM status register WEAKSIG position whether current demand signal is weak signal.
If when current demand signal is not weak signal, change step S301 over to;
If when current demand signal is weak signal, change step S303 over to.
In step S303, read the gain controlling grade of current tuner.
In step S304, read the level value of current frequency.
In step S305, judge whether the gain controlling grade is MT2060_VGAG_5DB.
If the gain controlling grade is MT2060_VGAG_5DB, change step S306 over to;
If the gain controlling grade is not MT2060_VGAG_5DB, then change step S309 over to.
In step S306, whether the decision level value is less than 0.
If level value less than 0, then enters step S307; If level value is not less than 0, then enter step S308.
In step S307, low two of gain register are set to 11, select gain controlling grade MT2060_VGAG_11DB, but enlarged the controlled range of current incoming level, change step S301 over to.
In step S308, low two of gain register are set to 00, select gain controlling grade MT2060_VGAG_0DB, but enlarged the controlled range of current incoming level, change step S301 over to.
In step S309, judge whether the gain controlling grade is MT2060_VGAG_11DB.
If the gain controlling grade is MT2060_VGAG_11DB, then change step S310 over to;
If the gain controlling grade is not MT2060_VGAG_11DB, then change step S311 over to.
In step S310, whether the decision level value is less than 0.
If level value is less than 0, then signal is too low, changes step S312 over to;
If level value is not less than 0, illustrate that signal is too high, changes step S313 over to.
In step S312, current signal intensity has exceeded the controlled range of tuner, and cable modem goes offline.
In step S313, low two of gain register are set to 01, select gain controlling grade MT2060_VGAG_5DB.
In step S311, whether the decision level value is less than 0.
If level value less than 0, illustrates that signal is too low, changes step S314 over to;
If level value is not less than 0, change among the step S312, go offline.
In step S314, low two of gain register are set to 01, select gain controlling grade MT2060_VGAG_5DB;
When signal changed after cable modem was reached the standard grade, constantly monitor current network state, when signal exceeds receivable level range, in time adjust the gain controlling grade of tuner, thereby enlarge the online level range of cable modem.
As shown in Figure 4, the cable modem of the embodiment of the invention comprises master chip 410 and tuner 420.Master chip 410 comprises QAM status register 411, the strong and weak judge module 412 of signal and level value judge module 413; Tuner 420 comprises that gain register 421 and gain controlling grade are provided with module 422 automatically.
The strong and weak judge module 412 of signal judges according to the value that reads the WEAKSIG position of QAM status register 411 whether current demand signal is weak signal, and the value when the WEAKSIG position is 1, and the expression signal is a weak signal.Value when the WEAKSIG position is 0, and the expression signal is normal; When current demand signal is weak signal, level value judge module 413 reads the level value of current frequency, whether the decision level value is less than 0, module 422 is set automatically for the gain controlling grade its result transmission, the gain controlling grade is provided with module 422 automatically and according to the level value that receives low two value of the gain register 421 of tuner 420 is set accordingly, changes the gain controlling grade.The level value that reads when level value judge module 413 is less than 0 the time, and low two the value that the gain controlling grade is provided with module 422 gain register 421 automatically is set to 11, improves the gain controlling grade; When the level value that reads when level value judge module 413 was not less than 0, low two value of gain register was set to 00, reduces the gain controlling grade.
As shown in Figure 5, the tuner 420 of cable modem also can comprise gain controlling grade judge module 423 in the middle of concrete enforcement, is used for judging when cable modem is reached the standard grade back signal generation current gain controlling grade.Back signal power judge module 412 bases of reaching the standard grade cable modem read the value of the WEAKSIG position of QAM status register and judge whether current demand signal is weak signal, and the value when the WEAKSIG position is 1, and the expression signal is a weak signal; Value when the WEAKSIG position is 0, and the expression signal is normal.When current demand signal was weak signal, gain controlling grade judge module 423 was judged by low two the value that reads gain register 421, is given level value judge module 413 with its result transmission.Wherein, gain controlling grade judge module 423 is judged current gain controlling grade by low two the value that reads gain register.Gain controlling grade judge module 423 judges that current gain controlling grade is not during for 5DB, judge whether to be 11DB again, and triggering level value judge module 413 reads the level value of current frequency, and whether the decision level value is provided with module 422 for the gain controlling grade its result transmission less than 0 automatically; The gain controlling grade is provided with module 422 automatically and according to the level value that receives low two value of tuner gain register is set accordingly, changes the gain controlling grade of tuner.When the gain controlling grade is 11DB, and level value is less than 0 o'clock, and cable modem goes offline; When the gain controlling grade is 11DB, and level value is not less than at 0 o'clock, and low two the value that the gain controlling grade is provided with module 422 gain register automatically is set to 01, improves the gain controlling grade; When the gain controlling grade is not to be 11DB, and level value judge module 413 decision level values are less than 0 o'clock, and low two the value that the gain controlling grade is provided with module 422 gain register automatically is set to 01, improves the gain controlling grade; When the gain controlling grade is not to be 11DB, and level value judge module 413 decision level values are not less than at 0 o'clock, and cable modem goes offline.
In the middle of concrete enforcement, gain controlling grade judge module 423 can be for being provided with one of tuner 420 inside that module 422 is connected independently module with the gain controlling grade automatically, also can be for being included in the module that the gain controlling grade is provided with module 422 inside automatically.
The gain adjusting method of the cable modem of the embodiment of the invention, judge by the value that reads QAM status register WEAKSIG position whether current demand signal is weak signal, when weak signal, read the level value of current frequency, according to level value the value of low two of gain register is carried out corresponding setting, automatically adjust the gain controlling grade of tuner, enlarged receivable level range.Thereby in last line process, cable modem can be reached the standard grade under more loose network environment, and the gain controlling grade of tuner is in time adjusted in the back of reaching the standard grade, thereby enlarges online level range.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. the gain adjusting method of a cable modem is characterized in that, said method comprising the steps of:
Judge whether current demand signal is weak signal;
When weak signal, read the level value of current frequency;
Automatically adjust the gain controlling grade according to described level value.
2. the gain adjusting method of cable modem as claimed in claim 1 is characterized in that, low two value of the gain register of described current gain controlling grade by reading tuner is determined.
3. the gain adjusting method of cable modem as claimed in claim 2 is characterized in that, the described step of adjusting the gain controlling grade automatically according to described level value is specially:
If the level value of the current frequency that reads then improves the gain controlling grade less than 0;
If the level value of the current frequency that reads is not less than 0, then reduce the gain controlling grade.
4. the gain adjusting method of cable modem as claimed in claim 1, it is characterized in that, after reaching the standard grade, cable modem gains when adjusting, if current the highest grade of gain controlling, and the level value of current frequency is less than zero, perhaps current gain controlling grade is minimum, and the level value of current frequency is not less than zero, then does the processing that goes offline.
5. a cable modem comprises master chip and tuner, and master chip comprises the QAM status register, and tuner comprises gain register, it is characterized in that, described master chip also comprises strong and weak judge module of signal and level value judge module; Described tuner comprises that also the gain controlling grade is provided with module automatically, wherein,
The strong and weak judge module of described signal, the value that is used to read the WEAKSIG position of QAM status register judges whether current demand signal is weak signal;
Described level value judge module is used for judging current level value when weak signal;
Described gain controlling grade is provided with module automatically, is used for changing according to the judged result of described level value judge module the value of described gain register, and the gain controlling grade is set.
6. cable modem as claimed in claim 5, it is characterized in that, the level value that described gain controlling grade is provided with the current frequency that module reads at described level value judge module automatically is less than improving the gain controlling grade at 0 o'clock, and the level value of the current frequency that reads at described level value judge module is not less than at 0 o'clock and reduces the gain controlling grade.
7. cable modem as claimed in claim 5 is characterized in that, described cable modem also comprises:
Gain controlling grade judge module is used to judge current gain controlling grade, module is set automatically for described gain controlling grade its result transmission.
8. cable modem as claimed in claim 7 is characterized in that, described gain controlling grade judge module is judged the gain controlling grade by low two the value that reads described gain register.
9. cable modem as claimed in claim 7 is characterized in that, described gain controlling grade judge module is positioned at described gain controlling grade inside modules or outside are set automatically.
10. cable modem as claimed in claim 7, it is characterized in that, described gain controlling grade is provided with module automatically and gains after cable modem is reached the standard grade when adjusting, in current the highest grade of gain controlling, and the level value of current frequency is less than zero, perhaps current gain controlling grade is minimum, and the level value of current frequency is done the processing that goes offline when being not less than zero.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2007100740951A CN101202562B (en) | 2007-04-24 | 2007-04-24 | Cable modem and gain adjustment method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007100740951A CN101202562B (en) | 2007-04-24 | 2007-04-24 | Cable modem and gain adjustment method thereof |
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| CN101202562A true CN101202562A (en) | 2008-06-18 |
| CN101202562B CN101202562B (en) | 2011-05-11 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101902419B (en) * | 2009-05-27 | 2013-02-13 | 鸿富锦精密工业（深圳）有限公司 | Cable modem and method thereof for keeping communication linkage |
| CN106301922A (en) * | 2016-08-16 | 2017-01-04 | 青岛海信宽带多媒体技术有限公司 | The method of adjustment of a kind of Tuner state and device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1144460C (en) * | 2000-11-24 | 2004-03-31 | 大连大显集团有限公司 | Downstream receiver circuit and upstream modulator circuit for cable modem in two-way cable TV network |
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2007
- 2007-04-24 CN CN2007100740951A patent/CN101202562B/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101902419B (en) * | 2009-05-27 | 2013-02-13 | 鸿富锦精密工业（深圳）有限公司 | Cable modem and method thereof for keeping communication linkage |
| CN106301922A (en) * | 2016-08-16 | 2017-01-04 | 青岛海信宽带多媒体技术有限公司 | The method of adjustment of a kind of Tuner state and device |
| CN106301922B (en) * | 2016-08-16 | 2020-02-04 | 青岛海信宽带多媒体技术有限公司 | Method and device for adjusting Tuner state |
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| CN101202562B (en) | 2011-05-11 |
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