CN101877771A - Automatic frequency control method for television - Google Patents
Automatic frequency control method for television Download PDFInfo
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- CN101877771A CN101877771A CN2009101071889A CN200910107188A CN101877771A CN 101877771 A CN101877771 A CN 101877771A CN 2009101071889 A CN2009101071889 A CN 2009101071889A CN 200910107188 A CN200910107188 A CN 200910107188A CN 101877771 A CN101877771 A CN 101877771A
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Abstract
The invention relates to an automatic frequency control method for a television, which comprises the following steps of: A) arranging a frequency monitoring control module in a main loop of a television software system; B) monitoring whether the frequency of a television signal channel is locked by using the frequency monitoring control module, if so, finishing the frequency monitoring and returning the main loop, otherwise, entering a step C; C) detecting whether synchronizing signals exist in video signals, if so, performing fine adjustment on the frequency of the television channel with short step and returning the step B, otherwise, entering a step D; and D) judging whether the adjusted frequency of the television signal channel exceeds the preset wide frequency adjustment range, if so, returning the main loop, otherwise, adjusting the frequency of the television channel with long step and jumping to the step C. The method has the traceable and controllable frequency range much wider than that of the prior art, and can ensure that the automatic control, tracing and locking of the frequency of the channel can be realized under the condition of frequency drift in any environment.
Description
Technical field
The present invention relates to the channel frequency control technology of television set, relate in particular to a kind of TV signal channel frequency wide region method of control automatically that realizes.
Background technology
Traditional TV channel Automatic Frequency Control, mainly be the situation of determination frequency locking on software, adopt short step-length fine setting when not locking, in the less deviation range at channel frequency center, finely tune, if still do not lock, just can be judged as no TV signal.The frequency range of adjusting is narrow, is difficult to satisfy to off-gauge TV signal and because of the requirement of the automatic control of the bigger TV signal channel frequency of a variety of causes frequency drift.For the FREQUENCY CONTROL of the TV signal of frequency drift wider range, need to adopt special technology to follow the tracks of to satisfy wide region, guarantee the signal controlling quality simultaneously again.
Number of patent application a kind of method that enlarges the AFC control range that has been 200610021616.2 Chinese disclosure of the Invention.By following the tracks of synchronizing signal the AFC control range is moved, reach the effect of expanding AFC control range, synchronizing signal is locked in the AFC control range after moving.But the frequency lock process relative complex of this invention, the time that locking process needs is longer, and expandable frequency range is positively biased 3M negative bias 2M to the maximum, and therefore a kind of method that realizes that quick wide region automatic frequency is adjusted need be provided.
Summary of the invention
Purpose of the present invention, providing a kind of television set can be at the control reception technique under the TV signal wide frequency ranges drift situation.Utilize original hardware can be realized in the television set signal a part, utilize a plurality of control informations to reach wide region by software and control the tracking channel frequency automatically as control information.
To achieve these goals, the invention provides a kind of wide region tv channel frequency method of control automatically that realizes, comprise the steps:
A. in the television software system major cycle, increase the frequency monitoring control module that is used for Monitoring and Controlling TV signal channel frequency;
B. in described frequency monitoring control module, whether the monitoring TV signal channel frequency locks; Locked as frequency, then finish frequency monitoring, return major cycle; Not locked as frequency, then enter step C;
C. the synchronizing signal of monitoring video signal; As synchronizing signal as described in monitoring, then short step-length inching tv channel frequency returns step B again; As synchronizing signal as described in not monitoring, then enter step D;
D. judge whether adjusted TV signal channel frequency has exceeded the scope that broadband is adjusted that presets; As scope as described in not super, then adjust tv channel frequency with big step-length, jump to step C again; As super scope, return major cycle;
Further, the frequency lock among the described step B is judged the realization by AFC (Automatic FrequencyControl, the abbreviation of automatic frequency control);
Further, the short step-length inching among the described step C is 50KHz;
Further, the big step-length adjustment among the described step D is 500KHz;
Further, the scope that presets the broadband adjustment among the described step D is the inclined to one side supreme inclined to one side 2MHz of 2MHz under described channel frequency center;
Further, the scope that presets the broadband adjustment among the described step D is the inclined to one side supreme inclined to one side 3MHz of 3MHz under described channel frequency center;
Further, the synchronizing signal among the described step C is the signal that the Video processing hardware circuit produces in the television set;
Further, described TV signal comprises the TV signal of standard television signal, non-standard video signals and wide frequency ranges drift;
Further, described method is tentatively controlled judgement when big step-length tv channel frequency is adjusted, lack the inching of step-length tv channel frequency according to the AFC lock condition again, realizes the TV signal tracking Control of wide frequency ranges.
Traditional technology generally mainly is to judge the situation of AFC (Automatic Frequency Control) locking on software, in the less deviation range at channel frequency center, finely tune when not locking, if still do not lock, just can be judged as no TV signal.The fine setting of conventional art mainly is the adjustment in the inclined to one side supreme inclined to one side 1MHz scope of 0.7MHz under the channel frequency center, and this can satisfy the requirement of the TV signal of standard, and for non-standard video signals, conventional art is difficult to satisfy the frequency departure of wide region.But and the frequency range of tracking Control among the present invention, much wideer than the scope that conventional art covers, guarantee that frequency drift in any environment can both realize controlling automatically the tracking lock channel frequency, make to adapt to TV signal under the various harsh conditions based on television set of the present invention.With the patent No. is that the method for 200610021616.2 the disclosed a kind of AFC of expansion control range of invention is compared, the present invention utilizes the synchronizing signal of vision signal to judge TV channel signal, when adjusting, big step-length tentatively controls judgement according to synchronizing signal earlier, lack the step frequency fine setting according to the situation of AFC locking again, big step-length and short step frequency adjustment combine, simple frequency lock process shortens the frequency lock time.Make software when big step-length is adjusted frequency, need not increase under the situation of television set hardware cost and can monitor useful signal well, and the frequency range that the present invention can monitor adjustment can reach up and down 3M even more partially, thereby can realize the TV signal tracking Control in the wideer frequency range, make the television set that adopts present technique can adapt to the demand in various markets.
Description of drawings
The invention will be further described below in conjunction with drawings and Examples, in the accompanying drawing:
Fig. 1 is the present invention's hardware signal of being correlated with and the interworking schematic diagram between the software control;
Fig. 2 is a system of the present invention major cycle flow chart;
Fig. 3 embodiment of the invention medium frequency Monitoring and Controlling module workflow diagram.
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 is used to explain the present invention, and be not used in qualification the present invention.
Fig. 1 is the present invention's hardware signal of being correlated with and the interworking schematic diagram between the software control.The course of work is as follows: AFC carries out tracking lock according to the centre frequency that is stored in the TV channel signal in the tuner related register to the TV signal that receives.Frequency monitoring control method according to the present invention is at first monitored the AFC lock-out state, if AFC locks onto TV signal, the user just can watch TV programme, if AFC non-locking TV signal is monitored the synchronizing signal that the Video processing hardware circuit produces again.State according to the synchronizing signal monitoring carries out different actions, if monitor synchronizing signal, then carries out the correspondent frequency adjustment, is the short step-length adjustment of 50KHz in the present embodiment, carries out the AFC locking subsequently again and judges, partial circulating fine setting frequency is until frequency lock; If do not monitor synchronizing signal, then carry out corresponding big step frequency adjustment, be 500KHz in the present embodiment, return the state of judging the synchronizing signal monitoring again.See frequency monitoring control flow chart shown in Figure 3 for details.Short step-length and big step-length adjustment meeting are carried out corresponding positively biased and negative bias adjustment according to the signal drift situation.
Fig. 2 is system's major cycle flow chart of implementing the inventive method.Frequency monitoring control module P100 of the present invention is increased in the major cycle of television software system, steps A promptly of the present invention.
Frequency monitoring control module P100 workflow diagram among Fig. 2 as shown in Figure 3.Whether frequency monitoring control module monitoring TV signal channel frequency locks, i.e. step B; In this way, then finish frequency monitoring, return major cycle; As not, then enter step C.The synchronizing signal of step C monitoring video signal: as monitor synchronizing signal, then short step-length inching tv channel frequency, return step B determination frequency lock condition again, partial circulating fine setting frequency is until frequency lock, when determining frequency lock, the tracking lock channel center frequency is finished in expression, finishes frequency monitoring control, returns major cycle; As do not monitor synchronizing signal, then enter step D; Step D judges whether adjusted TV signal channel frequency has exceeded the scope that broadband is adjusted that presets: as not, then big step-length is adjusted tv channel frequency, jumps to step C again; In this way, finish frequency monitoring, return major cycle.Shown in step B, C, D see that respectively frame of broken lines partly among Fig. 3.
Suppose that TV channel signal centre frequency fo is 471.25MHz, scope that can this channel of tracking lock after general television set is searched platform is from fo-0.7MHz to fo+1MHz.If this tv channel frequency for a certain reason, its centre frequency fo has become fo-1.5MHz, and then conventional art can followed the tracks of according to the AFC lock condition.Because its tracking can only be at fo-0.7MHz in the frequency range of fo+1MHz, therefore can't the tracking lock frequency have become the TV signal of fo-1.5MHz.That is to say the TV signal after the general television set that adopts conventional art can't trace into frequency change, the user also just can't see the TV programme after the frequency change.And the TV auto frequency control method that the present invention proposes is not when tracing into TV signal in the frequency range from fo-0.7MHz to fo+1MHz, and system carries out the frequency-tracking in the wideer scope automatically.Because AFC can't follow the tracks of when surpassing the AFC following range, adopt this moment the synchronizing information of vision signal to differentiate as preliminary judgement signal, in wide region, search for, when searching synchronizing signal, adopt AFC to carry out tracking Control again, until tracking lock tv channel frequency accurately, when not searching synchronizing signal, carry out the adjustment of adjusting frequency of big step-length, like this, change for a certain reason when big at tv channel frequency, adopt the television set of the method that the present invention proposes can also tracking lock to this television channel, the user can continue to watch the TV programme after the frequency change.
Present technique utilizes the synchronizing signal of vision signal to judge the judgement of TV channel signal, tentatively controls judgement according to synchronizing signal earlier when big step-length is adjusted, and lacks the step frequency fine setting according to the situation of AFC locking again.Make software when big step-length is adjusted frequency, can monitor useful signal well, thereby can realize the TV signal tracking Control in the wideer frequency range.
The method that the present invention proposes can realize the frequency-tracking control of wide frequency ranges, guarantee that in any environment frequency drift can both realize that channel frequency is followed the tracks of in control automatically, make to adapt to TV signal under the various harsh conditions based on television set of the present invention.Need not increase under the situation of television set hardware cost, realize that with the method for software the TV signal of wide frequency ranges is controlled automatically, make and adopt television set of the present invention can adapt to the demand in various markets.
In conjunction with the accompanying drawings embodiments of the invention are described above; but the present invention is not limited to above-mentioned embodiment; above-mentioned embodiment only is schematic; rather than it is restrictive; those of ordinary skill in the art is under enlightenment of the present invention; not breaking away from any modification of being done under the scope situation that aim of the present invention and claim protect, being equal to and replacing and improvement etc., all belong to protection scope of the present invention.
Claims (9)
1. realize the TV automatic frequency control method for one kind, it is characterized in that, may further comprise the steps:
A. in the television software system major cycle, increase the frequency monitoring control module (P100) that is used for Monitoring and Controlling TV signal channel frequency;
B. in described frequency monitoring control module (P100), whether the monitoring TV signal channel frequency locks; Locked as frequency, then finish frequency monitoring, return major cycle; Not locked as frequency, then enter step (C);
C. the synchronizing signal of monitoring video signal; As synchronizing signal as described in monitoring, then, return step (B) again to lack step-length inching tv channel frequency; As synchronizing signal as described in not monitoring, then enter step (D);
D. judge whether adjusted TV signal channel frequency has exceeded the scope that broadband is adjusted that presets; As scope as described in not super, then adjust tv channel frequency with big step-length, jump to step (C) again; As super scope, then return major cycle.
2. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that, the frequency lock judgement in the described step (B) realizes by AFC.
3. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that the short step-length inching in the described step (C) is 50KHz.
4. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that the big step-length adjustment in the described step (D) is 500KHz.
5. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that, the scope that presets the broadband adjustment in the described step (D) is the inclined to one side supreme inclined to one side 2MHz of 2MHz under described channel frequency center.
6. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that, the scope that presets the broadband adjustment in the described step (D) is the inclined to one side supreme inclined to one side 3MHz of 3MHz under described channel frequency center.
7. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that, the synchronizing signal in the described step (C) is the signal that the Video processing hardware circuit produces in the television set.
8. a kind of realization TV automatic frequency control method according to claim 1 is characterized in that, described TV signal comprises the TV signal of standard television signal, non-standard video signals and wide frequency ranges drift.
9. according to claim 1 and 2 described a kind of realization TV automatic frequency control method, it is characterized in that, described method is tentatively controlled judgement when big step-length tv channel frequency is adjusted, lack the inching of step-length tv channel frequency according to the AFC lock condition again, realize the TV signal tracking Control of wide frequency ranges.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101071889A CN101877771A (en) | 2009-04-30 | 2009-04-30 | Automatic frequency control method for television |
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| CN2009101071889A CN101877771A (en) | 2009-04-30 | 2009-04-30 | Automatic frequency control method for television |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103596059A (en) * | 2013-11-21 | 2014-02-19 | 乐视致新电子科技（天津）有限公司 | Intelligent-television media player and playing progress adjusting method thereof, and intelligent television |
| CN105812915A (en) * | 2014-12-30 | 2016-07-27 | 深圳Tcl数字技术有限公司 | Television channel searching method and system |
| CN111641793A (en) * | 2020-06-03 | 2020-09-08 | 海信视像科技股份有限公司 | Analog television playing method and display equipment |
-
2009
- 2009-04-30 CN CN2009101071889A patent/CN101877771A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103596059A (en) * | 2013-11-21 | 2014-02-19 | 乐视致新电子科技（天津）有限公司 | Intelligent-television media player and playing progress adjusting method thereof, and intelligent television |
| CN105812915A (en) * | 2014-12-30 | 2016-07-27 | 深圳Tcl数字技术有限公司 | Television channel searching method and system |
| CN105812915B (en) * | 2014-12-30 | 2019-09-20 | 深圳Tcl数字技术有限公司 | TV set to search programmes method and system |
| CN111641793A (en) * | 2020-06-03 | 2020-09-08 | 海信视像科技股份有限公司 | Analog television playing method and display equipment |
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Application publication date: 20101103 |