CN102131068A - Digital TV (television) tuner and filtering method thereof - Google Patents
Digital TV (television) tuner and filtering method thereof Download PDFInfo
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- CN102131068A CN102131068A CN2011100085824A CN201110008582A CN102131068A CN 102131068 A CN102131068 A CN 102131068A CN 2011100085824 A CN2011100085824 A CN 2011100085824A CN 201110008582 A CN201110008582 A CN 201110008582A CN 102131068 A CN102131068 A CN 102131068A
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Abstract
The invention particularly relates to a digital TV (television) tuner comprising a front-end broadband low-noise amplifier composed of a high-pass filter and a broadband low-noise amplifier, a down conversion module, a demodulation/decoding module and a capture filter, wherein the input end of the capture filter receives signals respectively from the I2C (Inter-Integrated Circuit) controllers of the front-end broadband low-noise amplifier, the demodulation/decoding module and the down conversion module, and the output end of the capture filter is connected with an amplifier in the down conversion module. The invention also discloses a filtering method of the capture filter. In the invention, the central frequency and 3dB bandwidth of the capture filter can be automatically adjusted based on the frequency and code rate of digital TV signals. Thus, the bandwidth matching degree of signals can be up to 98%, the noise signal bandwidth can be reduced as much as possible on the premise of having no signal energy loss, the signal-to-noise ratio is improved, and the sensitivity is high, thereby ensuring that the invention is applicable to receiving digital TV programs with various code rates and modes.
Description
Technical field
The present invention relates to satellite digital television receiving system, be specifically related to a kind of Digital Television tuner.
Background technology
Satellite digital television receiving system owing to the characteristics of its carrier frequency height, bandwidth (950MHz-2150MHz), generally adopts the demodulation mode of quadrature.The satellite digital TV signal has various code rate, and different code checks is to the bandwidth requirement difference of channel, and the narrow words of channel can be lost useful signal energy, and the wide words of channel can be introduced interference noise, thereby reduces the receiving sensitivity of Digital Television.Present Digital Television tuner, generally before this radiofrequency signal frequency conversion was become intermediate-freuqncy signal, and then intermediate-freuqncy signal is transformed into baseband signal, in processing procedure just to the intermediate-frequency bandwidth adjustment of dispersing, can not before entering frequency-conversion processing, signal carry out Filtering Processing to it by frequency and the code check according to signal, so cause pending modulation signal to lack the accuracy of bandwidth match, also increased the influence of unwanted signal to intermediate-freuqncy signal.
Summary of the invention
The purpose of this invention is to provide and a kind ofly can before signal enters frequency-conversion processing, carry out the Digital Television tuner of Filtering Processing to it by frequency and the code check according to signal, this Digital Television tuner bandwidth match degree height, signal to noise ratio height, highly sensitive.
For achieving the above object, the present invention has adopted following technical scheme, the present invention includes front-end wideband low noise amplifier, down conversion module, demodulating and decoding module that high pass filter, broadband low noise amplifier constitute, catch filter, described input of catching filter fetches the signal of the I 2C controller in front-end wideband low noise amplifier, demodulating and decoding module, down conversion module respectively, the amplifier in the output termination down conversion module.
Another program of the present invention is the filtering method of catching filter, comprises the method for adjustment of catching filter bandwidht and centre frequency:
The method of adjustment of catching filter bandwidht is as follows:
After the demodulating and decoding module receives intermediate-freuqncy signal, bandwidth to intermediate-freuqncy signal is analyzed, and sends 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth then, after this Serial No. is changed through number-Mo, form a control voltage Vc, adjust the bandwidth of catching filter;
The method of adjustment of catching the filter center frequency is as follows:
The I2C controller sends the center frequency information of selected digital signal by the I2C agreement to catching filter behind selected digital TV channel, catch after filter receives this information, and signal is converted into dc controling level, regulates its centre frequency;
Then, catch filter and the signal of importing is carried out Filtering Processing according to above-mentioned bandwidth value and center frequency value.
As shown from the above technical solution, the present invention can be according to the frequency and the code check of digital television signal, automatically regulate the centre frequency and the three dB bandwidth of catching filter, the bandwidth match degree that can make signal like this is up to 98%, under the condition of not losing signal energy, reduce the noise signal bandwidth as much as possible, improved signal to noise ratio, highly sensitive, the Digital Television that can be adapted under various code rate and the various modes receives.
Description of drawings
Fig. 1 is circuit theory diagrams of the present invention.
Embodiment
As shown in Figure 1, the present invention includes the front-end wideband low noise amplifier 17, down conversion module 16, the demodulating and decoding module 14 that constitute by high pass filter 1, broadband low noise amplifier 2, catch filter 13, the input of catching filter 13 fetches the signal of the I2C controller 10 in front-end wideband low noise amplifier 17, demodulating and decoding module 14, down conversion module 16 respectively, the amplifier 15 in the output termination down conversion module 16.
Wherein, down conversion module 16 comprises automatic gain control amplifier 3, orthogonal mixer 4, intermediate frequency amplifier 5, intermediate frequency low pass filter 6, intermediate frequency high-gain amplifier 7,90 degree phase-shifters 8, local oscillator 9, I2C controller 10, loop filter 11, crystal oscillator 12, demodulating and decoding module 14, amplifier 15.
Filtering method is promptly caught the filtering method of filter 13, comprises the method for adjustment of catching filter 13 bandwidth and centre frequency:
The method of adjustment of catching filter 13 bandwidth is as follows:
After demodulating and decoding module 14 receives intermediate-freuqncy signal, bandwidth to intermediate-freuqncy signal is judged, sends 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth then, after this Serial No. is changed through number-Mo, form a control voltage Vc, adjust the bandwidth of catching filter 13;
The method of adjustment of catching filter 13 centre frequencies is as follows:
Then, catch filter 13 and the signal of importing is carried out Filtering Processing according to above-mentioned bandwidth value and center frequency value.
Below in conjunction with Fig. 1 operation principle of the present invention is described, catch filter 13 after powering on and obtain an initial voltage, be used to adjust its bandwidth, 12C controller 10 is behind selected digital TV channel, send the center frequency information of selected digital signals by the I2C agreement to catching filter 13, catch after filter 13 receives this information, signal is converted into dc controling level, in order to regulate its centre frequency.Radiofrequency signal is amplified into through broadband low noise amplifier 2 through high pass filter 1 filtering low-frequency noise again and catches filter 13 and carry out Filtering Processing, pass through automatic gain control amplifier 3 then successively, orthogonal mixer 4 produces intermediate-freuqncy signal, intermediate frequency amplifier 5, intermediate frequency low pass filter 6 filtering high frequency clutters, intermediate frequency high-gain amplifier 7 enters demodulating and decoding module 14, after demodulating and decoding module 14 receives intermediate-freuqncy signal, bandwidth to signal is judged, send 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth then, after this Serial No. is changed through number-Mo, form a control voltage Vc, this voltage Vc is transmitted to and catches filter 13 and be used to adjust the bandwidth of catching filter 13.Radiofrequency signal through front-end wideband low noise amplifier 17 enters when catching filter 13 once more, to carry out filtering according to this bandwidth value, enter demodulating and decoding module 14 again after some the row amplifications of signal process, frequency conversion, the Filtering Processing then, demodulating and decoding module 14 produces a control voltage Vc once more, so adjustment repeatedly of this cyclic system of process, bandwidth value is more and more near the true bandwidth of radiofrequency signal, and last bandwidth match Du Keda 98% has improved signal to noise ratio greatly.
Claims (2)
1. Digital Television tuner, comprise the front-end wideband low noise amplifier (17), down conversion module (16), the demodulating and decoding module (14) that constitute by high pass filter (1), broadband low noise amplifier (2), it is characterized in that: the present invention also comprises and catches filter (13), described input of catching filter (13) fetches the signal of the I2C controller (10) in front-end wideband low noise amplifier (17), demodulating and decoding module (14), down conversion module (16) respectively, the amplifier (15) in the output termination down conversion module (16).
2. filtering method comprises the method for adjustment of catching filter (13) bandwidth and centre frequency:
The method of adjustment of catching filter (13) bandwidth is as follows:
After demodulating and decoding module (14) receives intermediate-freuqncy signal, bandwidth to intermediate-freuqncy signal is judged, sends 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth then, after this Serial No. is changed through number-Mo, form a control voltage Vc, adjust the bandwidth of catching filter (13);
The method of adjustment of catching filter (13) centre frequency is as follows:
I2C controller (10) is behind selected digital TV channel, send the center frequency information of selected digital signal by the I2C agreement to catching filter (13), catch after filter (13) receives this information, signal is converted into dc controling level, regulate its centre frequency;
Then, catch filter (13) and the signal of importing is carried out Filtering Processing according to above-mentioned bandwidth value and center frequency value.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201110008582 CN102131068B (en) | 2011-01-16 | 2011-01-16 | Digital TV (television) tuner and filtering method thereof |
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| CN 201110008582 CN102131068B (en) | 2011-01-16 | 2011-01-16 | Digital TV (television) tuner and filtering method thereof |
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| CN102131068B CN102131068B (en) | 2013-01-23 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103167254A (en) * | 2013-03-29 | 2013-06-19 | 无锡盟欣智能科技有限公司 | Tuner circuit |
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| CN2329125Y (en) * | 1998-06-04 | 1999-07-14 | 成都新泰克电子有限公司 | Tuner special for digital wired TV |
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| CN101287077A (en) * | 2007-11-21 | 2008-10-15 | 雷科通技术（杭州）有限公司 | Novel integrated bidirectional tuner |
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| US20090086859A1 (en) * | 2007-09-27 | 2009-04-02 | Sanyo Electric Co., Ltd. | Receiving unit receiving digital television broadcasting |
| CN201328153Y (en) * | 2008-12-05 | 2009-10-14 | 中山圣马丁电子元件有限公司 | Multi-functional KU frequency-band satellite receiving high-frequency head and corresponding receiving device |
| CN201383849Y (en) * | 2009-03-13 | 2010-01-13 | 深圳市中龙通电子科技有限公司 | Digital-analog integrated tuner with FM receiving function |
| CN201557188U (en) * | 2009-09-30 | 2010-08-18 | 陕西凌华电子有限公司 | Cable digital tuner |
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2011
- 2011-01-16 CN CN 201110008582 patent/CN102131068B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2329125Y (en) * | 1998-06-04 | 1999-07-14 | 成都新泰克电子有限公司 | Tuner special for digital wired TV |
| CN2634754Y (en) * | 2003-08-19 | 2004-08-18 | 四川长虹电器股份有限公司 | High sensitive receiving tuner |
| US20090086859A1 (en) * | 2007-09-27 | 2009-04-02 | Sanyo Electric Co., Ltd. | Receiving unit receiving digital television broadcasting |
| CN101287077A (en) * | 2007-11-21 | 2008-10-15 | 雷科通技术（杭州）有限公司 | Novel integrated bidirectional tuner |
| CN201142720Y (en) * | 2007-12-29 | 2008-10-29 | 深圳市同洲电子股份有限公司 | Radio-frequency head, satellite digital television signal receiving and processing circuit and receiving system |
| CN201328153Y (en) * | 2008-12-05 | 2009-10-14 | 中山圣马丁电子元件有限公司 | Multi-functional KU frequency-band satellite receiving high-frequency head and corresponding receiving device |
| CN201383849Y (en) * | 2009-03-13 | 2010-01-13 | 深圳市中龙通电子科技有限公司 | Digital-analog integrated tuner with FM receiving function |
| CN201557188U (en) * | 2009-09-30 | 2010-08-18 | 陕西凌华电子有限公司 | Cable digital tuner |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103167254A (en) * | 2013-03-29 | 2013-06-19 | 无锡盟欣智能科技有限公司 | Tuner circuit |
| CN103167254B (en) * | 2013-03-29 | 2016-02-24 | 深圳英盟欣科技有限公司 | High frequency tuner circuit |
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| CN102131068B (en) | 2013-01-23 |
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Address after: 230088 ginkgo Road, hi tech Zone, Anhui, Hefei, 108 Patentee after: Hefei radio communication Polytron Technologies Inc. Address before: 230088 intersection of camphor road and ginkgo Road, Hefei hi tech Industrial Development Zone, Anhui, China Patentee before: HEFEI RADIO TECHNOLOGY Co.,Ltd. |
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Denomination of invention: Digital TV (television) tuner and filtering method thereof Effective date of registration: 20190830 Granted publication date: 20130123 Pledgee: Merchants Bank Hefei Dongmen branch Pledgor: HEFEI RADIO COMMUNICATION TECHNOLOGY CO.,LTD. Registration number: Y2019340000034 |
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Date of cancellation: 20200818 Granted publication date: 20130123 Pledgee: Merchants Bank Hefei Dongmen branch Pledgor: HEFEI RADIO COMMUNICATION TECHNOLOGY Co.,Ltd. Registration number: Y2019340000034 |
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Denomination of invention: Digital TV High Frequency Headers and Their Filtering Methods Effective date of registration: 20230504 Granted publication date: 20130123 Pledgee: Industrial Bank Limited by Share Ltd. Hefei branch Pledgor: HEFEI RADIO COMMUNICATION TECHNOLOGY CO.,LTD. Registration number: Y2023980039707 |
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Granted publication date: 20130123 Pledgee: Industrial Bank Limited by Share Ltd. Hefei branch Pledgor: HEFEI RADIO COMMUNICATION TECHNOLOGY CO.,LTD. Registration number: Y2023980039707 |