CN101674440A - Method for processing digital television signal offset - Google Patents
Method for processing digital television signal offset Download PDFInfo
- Publication number
- CN101674440A CN101674440A CN200810216226A CN200810216226A CN101674440A CN 101674440 A CN101674440 A CN 101674440A CN 200810216226 A CN200810216226 A CN 200810216226A CN 200810216226 A CN200810216226 A CN 200810216226A CN 101674440 A CN101674440 A CN 101674440A
- Authority
- CN
- China
- Prior art keywords
- signal
- frequency
- parameter value
- optimum
- correspondence
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Abstract
The invention provides a method for processing digital television signal offset, which is suitable for the technical field of digital television. The method comprises the following steps: a. arranginga low noise blockconverter at a frequency behind an offset step S of a channel center frequency in the frequency increase direction, acquiring signal parameter values from a demodulator chip and determining an optimum signal frequency point in the frequency increase direction by comparing the signal parameter values which correspond to frequencies behind various groups of offset step S; arrangingthe low noise blockconverter at the frequency behind the offset step S of the channel center frequency in the frequency decrease direction, acquiring signal parameter values from the demodulator chipand determining an optimum signal frequency point in the frequency decrease direction; and b. comparing the signal parameter values which correspond to the optimum signal frequency points in the frequency increase direction and the frequency decrease direction and determining an optimum signal frequency point. The technical scheme enables the digital television to correct the frequency offset anda digital television receiving system to be in an optimum signal receiving state.
Description
Technical field
The invention belongs to the digital television techniques field, relate in particular to the processing method of digital television signal offset.
Background technology
In the transmission course of TV signal, because the influence of transmitter, transmission equipment, transmission channel environment, all can there be skew to a certain extent in signal frequency.Search and tracking signal all are that the buckle variation of line realizes according to frequency in simulated television, just come scanning frequency with certain step-length, just can know the quality situation of anolog TV signals according to the signal amplitude on each frequency, this method itself just can effectively be handled the influence of frequency shift (FS) to signal.
In digital television system, Digital Television be with channel center frequency as channel frequency, audio/video information through chnnel coding and the modulation after be evenly distributed in the 8M bandwidth of radio frequency (RF) signal.After tuner (Tuner) was locked in the centre frequency of channel, output intermediate frequency (IF) signal was to demodulation (Demodulator) chip of rear end, and demodulation chip carries out recovering baseband signal after the A/D conversion to intermediate-freuqncy signal.Therefore intermediate-freuqncy signal has a suitable amplitude just can carry out the A/D conversion, just can not judge signal quality by the amplitude of intermediate frequency.
If this moment, skew appearred in the centre frequency of signal, when Tuner changed to IF with frequency by RF, SAW (surface acoustic wave) low pass filter phase noise can occur when the adjacent channel component is suppressed.In existing product design, most ways all are that the rectification ability that depends on Tuner and Demodulator device itself is corrected frequency offset issues, promptly when the Demodulator chip is handled the IF signal, can adapt to certain frequency shift (FS) by automatic frequency correction, but because the front end RF signal itself is offset, the frequency deviation range that only relies on rear end IF to proofread and correct is very limited, and therefore, existing technical scheme still can not reach desirable effect to the processing of frequency shift (FS).
Summary of the invention
The object of the present invention is to provide a kind of processing method of digital television signal offset, be intended to solve the Digital Television that exists in the prior art can not reach ideal effect to the processing of frequency shift (FS) problem.
The present invention is achieved in that a kind of processing method of digital television signal offset, and described method comprises the steps:
A, on frequency increases direction, with the frequency configuration tuner behind the channel center frequency skew step-length S, treat that tuner locking back obtains signal parameter value from demodulation chip, by comparison, determine that frequency increases the optimum signal Frequency point on the direction to the signal parameter value of the frequency correspondence behind each group skew step-length S; Reduce on the direction in frequency, with the frequency configuration tuner behind the channel center frequency skew step-length S, treat that tuner locking back obtains signal parameter value from demodulation chip, by comparison, determine that frequency reduces the optimum signal Frequency point on the direction to the signal parameter value of the frequency correspondence behind each group skew step-length S;
B, more described frequency increase optimum signal Frequency point and frequency on the direction and reduce the corresponding signal parameter value of optimum signal Frequency point on the direction, determine the optimum signal Frequency point.
Wherein step a also comprises:
Described tuner locking back output intermediate-freuqncy signal is to described demodulation chip, and described demodulation chip feedback intermediate-frequency gain is controlled described tuner, and described tuner obtains described signal parameter value from described demodulation chip after locking described intermediate-frequency gain control.
Described signal parameter value specifically comprises the value of intensity, signal to noise ratio and the error rate.
The described comparison of passing through the signal parameter value of the frequency correspondence behind each group skew step-length S, obtain the optimum signal Frequency point that frequency increases on the direction and/or frequency reduces on the direction and specifically comprise:
If described signal strength values continues to reduce, be the optimum signal Frequency point with the pairing frequency of signal strength signal intensity maximum; If described signal strength signal intensity continues to increase, then the increase of judging signal strength signal intensity according to the value of the described signal to noise ratio and the error rate whether since noise cause, if not, then the frequency with the strong maximum correspondence of signal is the optimum signal Frequency point; The value of error rate minimum is as the optimum signal Frequency point if the signal to noise ratio maximum, is then selected in the increase of signal strength signal intensity owing to noise causes.
Whether the increase of judging signal strength signal intensity according to the value of the described signal to noise ratio and the error rate is because noise specifically comprising of causing:
When described signal strength signal intensity continues to increase, whether continue to increase by the described signal to noise ratio of relatively judging the signal to noise ratio parameter value of the frequency correspondence behind each group skew step-length S, if, then whether continue to increase by the described error rate of relatively judging to the error rate parameter value of the frequency correspondence behind each group skew step-length S, if the increase of then judging described signal strength signal intensity is because signal noise causes.
Wherein step b specifically comprises:
B1, comparison frequency increase the error rate parameter value of optimum signal Frequency point correspondence on the direction and the error rate parameter value that frequency reduces optimum signal Frequency point correspondence on the direction, if both differences, then the frequency with smaller error rate parameter value correspondence is the optimum signal Frequency point; If both are identical, then comparison frequency increases the signal to noise ratio parameter value of optimum signal Frequency point correspondence on the direction and the signal to noise ratio parameter value that frequency reduces optimum signal Frequency point correspondence on the direction, is the signal frequency point of the best with the frequency of bigger signal to noise ratio parameter value correspondence; If error rate parameter value is all identical with the signal to noise ratio parameter value, then comparison frequency increases the signal strength parameter value of optimum signal Frequency point correspondence on the direction and the signal strength parameter value that frequency reduces optimum signal Frequency point correspondence on the direction, is the optimum signal Frequency point with the frequency of bigger signal strength parameter value correspondence.
The present invention overcomes the deficiencies in the prior art, on the frequency increase/minimizing direction with the frequency configuration tuner behind the signal center frequency skew step-length S, treat that tuner locking back obtains signal parameter value from demodulation chip, by comparison to the signal parameter value of the frequency correspondence behind each group skew step-length S, determine that frequency increases optimum signal Frequency point on the direction and frequency and reduces optimum signal Frequency point on the direction, more described then frequency increases optimum signal Frequency point and frequency on the direction and reduces the corresponding signal parameter value of optimum signal Frequency point on the direction, determines the optimum signal Frequency point.Technical scheme provided by the invention makes Digital Television to correct frequency shift (FS), makes digital TV receiving system be in best signal accepting state.
Description of drawings
Fig. 1 is an embodiment of the invention flow chart;
Fig. 2 is the particular flow sheet that increases/reduce the optimum signal Frequency point on the direction in frequency that the embodiment of the 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.
In the embodiment of the invention, system reads NVRAM (Non-Volatile RAM, non-changeability RAM) channel data of preserving in also is set to tuner, the output intermediate-freuqncy signal is to demodulation chip after the tuner locking frequency, and demodulation chip feedback intermediate-frequency gain control (AGC Automatic Gain Control) is to tuner; After the tremendously high frequency head AGC locking, system reads the parameter value of signal from demodulation chip: the value of signal strength signal intensity (Strength), signal to noise ratio (SNR Signal to Noise Ratio), the error rate (BER Bit ErrorRate) parameter; System is according to the direction of frequency values increase then, at every turn to lock tuner again after the step-length S deviation frequency, again obtain the relevant parameters such as signal strength signal intensity, signal to noise ratio and the error rate of the frequency correspondence behind the skew step-length S from demodulation chip, and compare, thereby obtain to increase optimum signal Frequency point on the direction in frequency with the parameter that obtains previously; The direction that system reduces according to frequency values, at every turn to lock tuner again after the step-length S deviation frequency, again obtain the relevant parameters such as signal strength signal intensity, signal to noise ratio and the error rate of the frequency correspondence behind the skew step-length S from demodulation chip, and compare, thereby obtain to reduce optimum signal Frequency point on the direction in frequency with the parameter that obtains previously; System draws corresponding optimum signal Frequency point by frequency being increased the isoparametric comparison of intensity, signal to noise ratio and the error rate that direction and frequency reduce to obtain on the direction optimum signal Frequency point.
Wherein, the value of skew step-length S is relevant with the characteristic of specific product, during the practical application technical solution of the present invention, can determine according to specific product.
Embodiment of the invention flow chart specifically comprises following step as shown in Figure 1:
1, system uses the channel information of preserving among the NVRAM after startup, and tuner is set, and perhaps according to channel table tuner is set by software when searching platform;
2, tuner is after locking frequency, and the output intermediate-freuqncy signal is to demodulation chip, and the demodulation chip feedback AGC locks up to tuner AGC to tuner;
3, system reads the value of signal strength signal intensity, signal to noise ratio and error rate parameter from demodulation chip, as the fiducial value of follow-up comparison;
4, system is a starting point with existing frequency (channel center frequency), direction according to the frequency values increase, again lock tuner with the frequency behind the skew step-length S at every turn, again from demodulation chip, obtain the value of one group of signal strength signal intensity, signal to noise ratio and the error rate parameter of the frequency correspondence behind each time skew step-length S, and compare, thereby obtain to increase optimum signal Frequency point (idiographic flow is referring to flow chart 2) on the direction in frequency with the parameter that obtains previously;
5, system is a starting point with existing frequency, the direction that reduces according to frequency values, again lock tuner with the frequency behind the skew step-length S at every turn, again from demodulation chip, obtain the value of one group of signal strength signal intensity, signal to noise ratio and the error rate parameter of the frequency correspondence behind each time skew step-length S, and compare, thereby obtain to reduce optimum signal Frequency point (idiographic flow is referring to flow chart 2) on the direction in frequency with the parameter that obtains previously;
6, comparison system increases and frequency reduces the value of intensity, signal to noise ratio and error rate parameter that direction obtains the optimum signal Frequency point in frequency, and the order of comparison is respectively the error rate, signal to noise ratio and signal strength signal intensity; If just the error rate has difference, then the frequency with one group of less parameter correspondence of the error rate is the optimum signal Frequency point; If error rate no change, then the frequency with one group of bigger parameter correspondence of signal to noise ratio is the signal frequency point of the best; Same, if the error rate, signal to noise ratio no change all, then the frequency with one group of bigger parameter correspondence of signal strength values is the optimum signal Frequency point.
Specifically, system increases in frequency/reduces on the direction and locks tuner again with the frequency behind the migration S, again from demodulation chip, obtain the value of signal strength signal intensity, signal to noise ratio and error rate parameter, as follows thereby acquisition increases/reduce the procedure declaration of the optimum signal Frequency point on the direction in frequency:
If described signal strength values continues to reduce, be the optimum signal Frequency point with the pairing frequency of signal strength signal intensity maximum; If described signal strength signal intensity continues to increase, then the increase of judging signal strength signal intensity according to the value of the described signal to noise ratio and the error rate whether since noise cause, if not, then the frequency with the strong maximum correspondence of signal is the optimum signal Frequency point; The value of error rate minimum is as the optimum signal Frequency point if the signal to noise ratio maximum, is then selected in the increase of signal strength signal intensity owing to noise causes.
Wherein, whether the increase of judging signal strength signal intensity according to the value of the signal to noise ratio and the error rate is because noise specifically comprising of causing: when described signal strength signal intensity continues to increase, whether continue to increase by the described signal to noise ratio of relatively judging the signal to noise ratio parameter value of the frequency correspondence behind each group skew step-length S, if, then whether continue to increase by the described error rate of relatively judging to the error rate parameter value of the frequency correspondence behind each group skew step-length S, if the increase of then judging described signal strength signal intensity is because signal noise causes.
Idiographic flow is as shown in Figure 2:
1, a skew of the increase/minimizing step-length S on existing frequency of system is with the frequency configuration tuner behind the skew step-length S;
2, tuner is after locking frequency, and the output intermediate-freuqncy signal is to demodulation chip, and the demodulation chip feedback AGC locks up to tuner AGC to tuner;
3, system reads the value of signal strength signal intensity, signal to noise ratio and error rate parameter from demodulation chip;
Does 4, the signal strength parameter value increase? if change step 5, otherwise change step 8;
Is 5, signal to noise ratio currency (Current_SNR) greater than or equal to a snr value (Last_SNR)? if change step 1, otherwise change step 6;
Is 6, error rate currency (Current_BER) greater than or equal to a ber value (Last_BER)? if change step 7, otherwise change step 1;
7, preserve the frequency of a last signal strength signal intensity, a last signal to noise ratio and a last error rate correspondence as current optimum signal Frequency point;
If 8 signal strength signal intensities reduce, system variable Count counting adds 1;
9, with the cyclic variable count value N contrast of Count and default,, otherwise change step 1 if Count＞N changes step 10;
10, the explanation signal strength signal intensity continues to reduce, and then preserving the pairing frequency of signal strength signal intensity maximum is the optimum signal Frequency point.
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 (6)
1, a kind of processing method of digital television signal offset is characterized in that, described method comprises the steps:
A, on frequency increases direction, with the frequency configuration tuner behind the channel center frequency skew step-length S, treat that tuner locking back obtains signal parameter value from demodulation chip, by comparison, determine that frequency increases the optimum signal Frequency point on the direction to the signal parameter value of the frequency correspondence behind each group skew step-length S; Reduce on the direction in frequency, with the frequency configuration tuner behind the channel center frequency skew step-length S, treat that tuner locking back obtains signal parameter value from demodulation chip, by comparison, determine that frequency reduces the optimum signal Frequency point on the direction to the signal parameter value of the frequency correspondence behind each group skew step-length S;
B, more described frequency increase optimum signal Frequency point and frequency on the direction and reduce the corresponding signal parameter value of optimum signal Frequency point on the direction, determine the optimum signal Frequency point.
2, method according to claim 1 is characterized in that, wherein step a also comprises:
Described tuner locking back output intermediate-freuqncy signal is to described demodulation chip, and described demodulation chip feedback intermediate-frequency gain is controlled described tuner, and described tuner obtains described signal parameter value from described demodulation chip after locking described intermediate-frequency gain control.
3, method according to claim 1 is characterized in that, described signal parameter value specifically comprises the value of intensity, signal to noise ratio and the error rate.
4, method according to claim 3 is characterized in that, the described comparison of passing through the signal parameter value of the frequency correspondence behind each group skew step-length S is obtained the optimum signal Frequency point that frequency increases on the direction and/or frequency reduces on the direction and specifically comprised:
If described signal strength values continues to reduce, be the optimum signal Frequency point with the pairing frequency of signal strength signal intensity maximum; If described signal strength signal intensity continues to increase, then the increase of judging signal strength signal intensity according to the value of the described signal to noise ratio and the error rate whether since noise cause, if not, then the frequency with the strong maximum correspondence of signal is the optimum signal Frequency point; The value of error rate minimum is as the optimum signal Frequency point if the signal to noise ratio maximum, is then selected in the increase of signal strength signal intensity owing to noise causes.
5, method according to claim 4 is characterized in that, whether the increase of judging signal strength signal intensity according to the value of the described signal to noise ratio and the error rate is because noise specifically comprising of causing:
When described signal strength signal intensity continues to increase, whether continue to increase by the described signal to noise ratio of relatively judging the signal to noise ratio parameter value of the frequency correspondence behind each group skew step-length S, if, then whether continue to increase by the described error rate of relatively judging to the error rate parameter value of the frequency correspondence behind each group skew step-length S, if the increase of then judging described signal strength signal intensity is because signal noise causes.
6, method according to claim 3 is characterized in that, wherein step b specifically comprises:
B1, comparison frequency increase the error rate parameter value of optimum signal Frequency point correspondence on the direction and the error rate parameter value that frequency reduces optimum signal Frequency point correspondence on the direction, if both differences, then the frequency with smaller error rate parameter value correspondence is the optimum signal Frequency point; If both are identical, then comparison frequency increases the signal to noise ratio parameter value of optimum signal Frequency point correspondence on the direction and the signal to noise ratio parameter value that frequency reduces optimum signal Frequency point correspondence on the direction, is the signal frequency point of the best with the frequency of bigger signal to noise ratio parameter value correspondence; If error rate parameter value is all identical with the signal to noise ratio parameter value, then comparison frequency increases the signal strength parameter value of optimum signal Frequency point correspondence on the direction and the signal strength parameter value that frequency reduces optimum signal Frequency point correspondence on the direction, is the optimum signal Frequency point with the frequency of bigger signal strength parameter value correspondence.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810216226XA CN101674440B (en) | 2008-09-12 | 2008-09-12 | Method for processing digital television signal offset |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810216226XA CN101674440B (en) | 2008-09-12 | 2008-09-12 | Method for processing digital television signal offset |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101674440A true CN101674440A (en) | 2010-03-17 |
| CN101674440B CN101674440B (en) | 2012-03-21 |
Family
ID=42021398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200810216226XA Expired - Fee Related CN101674440B (en) | 2008-09-12 | 2008-09-12 | Method for processing digital television signal offset |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101674440B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102256083A (en) * | 2011-07-01 | 2011-11-23 | 南京熊猫信息产业有限公司 | Method for accelerating channel demodulation speed of wired television STB (Set Top Box) |
| CN102315884A (en) * | 2010-06-29 | 2012-01-11 | 北京创毅视讯科技有限公司 | Method and device for reducing communication signal interference in mobile television signal |
| CN103227909A (en) * | 2013-04-19 | 2013-07-31 | 深圳创维－Rgb电子有限公司 | Signal processing method and device for silicon tuner |
| CN105450572A (en) * | 2014-08-27 | 2016-03-30 | 华为技术有限公司 | OFDM system and center frequency adjusting method thereof |
| WO2017101264A1 (en) * | 2015-12-17 | 2017-06-22 | 深圳Tcl数字技术有限公司 | Channel searching method and system for television terminal |
| CN115333654A (en) * | 2022-10-13 | 2022-11-11 | 成都爱旗科技有限公司 | Frequency offset detection method, system and electronic equipment |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004328054A (en) * | 2003-04-21 | 2004-11-18 | Sharp Corp | Pll circuit, television receiver using the same, beat improving method for television receiver |
| JP4656836B2 (en) * | 2003-12-19 | 2011-03-23 | パナソニック株式会社 | Synchronous clock generation apparatus and synchronous clock generation method |
| US8055226B2 (en) * | 2006-10-18 | 2011-11-08 | Tektronix, Inc. | Frequency response correction for a receiver having a frequency translation device |
| CN101242391B (en) * | 2007-02-09 | 2011-08-31 | 卓胜微电子（上海）有限公司 | Carrier frequency recovery and tracking method |
-
2008
- 2008-09-12 CN CN200810216226XA patent/CN101674440B/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102315884A (en) * | 2010-06-29 | 2012-01-11 | 北京创毅视讯科技有限公司 | Method and device for reducing communication signal interference in mobile television signal |
| CN102256083A (en) * | 2011-07-01 | 2011-11-23 | 南京熊猫信息产业有限公司 | Method for accelerating channel demodulation speed of wired television STB (Set Top Box) |
| CN103227909A (en) * | 2013-04-19 | 2013-07-31 | 深圳创维－Rgb电子有限公司 | Signal processing method and device for silicon tuner |
| CN103227909B (en) * | 2013-04-19 | 2016-03-23 | 深圳创维－Rgb电子有限公司 | For signal processing method and the device of silicon tuner |
| CN105450572A (en) * | 2014-08-27 | 2016-03-30 | 华为技术有限公司 | OFDM system and center frequency adjusting method thereof |
| CN105450572B (en) * | 2014-08-27 | 2018-12-25 | 华为技术有限公司 | Ofdm system and its centre frequency method of adjustment |
| WO2017101264A1 (en) * | 2015-12-17 | 2017-06-22 | 深圳Tcl数字技术有限公司 | Channel searching method and system for television terminal |
| CN115333654A (en) * | 2022-10-13 | 2022-11-11 | 成都爱旗科技有限公司 | Frequency offset detection method, system and electronic equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101674440B (en) | 2012-03-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101147393B (en) | Device and method for tuning radio frequency signal | |
| US7668260B2 (en) | Method of and apparatus for detecting impulsive noise, method of operating a demodulator, demodulator and radio receiver | |
| US6771719B1 (en) | Automatic gain control method and its system | |
| US7233629B2 (en) | Adjusting a receiver | |
| CN101674440B (en) | Method for processing digital television signal offset | |
| US20020073436A1 (en) | Tuner | |
| CN1146120A (en) | Digital carrier wave restoring device and method therefor in television signal receiver | |
| KR100480646B1 (en) | Automatic gain controller providing for stable signal acquisition and tracking adaptive in high-noise multipath channels, digital television receiver comprising it and method thereof | |
| US20110019783A1 (en) | Receiver and electronic device using the same | |
| US20100238358A1 (en) | Adjacent channel power scan | |
| RU2594764C2 (en) | Receiving device, receiving method and program | |
| JP2005130076A (en) | Digital broadcast receiver | |
| US7480350B2 (en) | Carrier recovery apparatus and broadcasting receiver using the same | |
| KR100379490B1 (en) | AGC apparatus in digital TV receiver | |
| JP2010045652A (en) | Receiving system, control method of receiving system, control program of receiving system, and recording medium having recorded control program of receiving system | |
| JP4818229B2 (en) | Tuner circuit and receiving apparatus | |
| KR101185561B1 (en) | Apparatus and method for controlling gain of broadcasting receiver automatically | |
| JP2006148592A (en) | Cofdm modulation signal receiver | |
| JP2005102008A (en) | Receiver and receiving method | |
| KR100309097B1 (en) | Method and apparatus of fine tuning for television receiver and method and apparatus of matching vsb signal | |
| JP2006270582A (en) | Receiving circuit | |
| JP5574531B2 (en) | transceiver | |
| JP2021093615A (en) | Radio communication device and receiving device | |
| JP2004221831A (en) | Demodulator | |
| KR20050076882A (en) | Agc apparatus in digital tv receiver |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120321 |