CN102131068B - Digital TV (television) tuner and filtering method thereof - Google Patents
Digital TV (television) tuner and filtering method thereof Download PDFInfo
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- CN102131068B CN102131068B CN 201110008582 CN201110008582A CN102131068B CN 102131068 B CN102131068 B CN 102131068B CN 201110008582 CN201110008582 CN 201110008582 CN 201110008582 A CN201110008582 A CN 201110008582A CN 102131068 B CN102131068 B CN 102131068B
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- 238000001914 filtration Methods 0.000 title claims abstract description 16
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 17
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- 230000003321 amplification Effects 0.000 description 1
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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 because its carrier frequency is high, the characteristics of bandwidth (950MHz-2150MHz), generally adopts the demodulation mode of quadrature.Satellite digital television signal has various code rate, and different code checks is different to the bandwidth requirement 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 the 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 impact of unwanted signal on intermediate-freuqncy signal.
Summary of the invention
The purpose of this invention is to provide and a kind ofly can be before signal enters frequency-conversion processing carry out the Digital Television tuner that filtering is processed according to frequency and the code check of signal to it, this Digital Television tuner bandwidth match degree is high, signal to noise ratio is high, 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 consist of, catch filter, described input of catching filter fetches respectively the I in front-end wideband low noise amplifier, demodulating and decoding module, down conversion module
2The signal of C controller, 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 then sends 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth, after this Serial No. is changed through number-mould, form a control voltage Vc, adjust the bandwidth of catching filter;
The method of adjustment of catching the filter center frequency is as follows:
I
2The C controller passes through I behind selected digital TV channel
2The C agreement is to the center frequency information of catching filter and send selected digital signal, catches after filter receives this information, and signal is converted into dc controling level, regulates its centre frequency;
Then, catch filter and according to above-mentioned bandwidth value and center frequency value the signal of inputting is carried out the filtering processing.
As shown from the above technical solution, the present invention can be according to frequency and the code check of digital television signal, automatically regulate centre frequency and the three dB bandwidth of catching filter, can make like this bandwidth match degree of signal up to 98%, under the condition of not losing signal energy, reduce as much as possible the noise signal bandwidth, improved signal to noise ratio, highly sensitive, can be adapted to the Digital TV Receiving under various code rate and the various modes.
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 are consisted of by high pass filter 1, broadband low noise amplifier 2, catch filter 13, the input of catching filter 13 fetches respectively the I in front-end wideband low noise amplifier 17, demodulating and decoding module 14, down conversion module 16
2The signal of C controller 10, 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, I
2C controller 10, loop filter 11, crystal oscillator 12, demodulating and decoding module 14, amplifier 15.
Filtering method is namely 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, then sends 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth, after this Serial No. is changed through number-mould, 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:
I
2 C controller 10 passes through I behind selected digital TV channel
2The C agreement is to the center frequency information of catching filter 13 and send selected digital signals, catches after filter 13 receives this information, and signal is converted into dc controling level, regulates its centre frequency;
Then, catch filter 13 and according to above-mentioned bandwidth value and center frequency value the signal of inputting is carried out the filtering processing.
Below in conjunction with Fig. 1 operation principle of the present invention is described, catches filter 13 after powering on and obtain an initial voltage, be used for adjusting its bandwidth, I
2C controller 10 passes through I behind selected digital TV channel
2The C agreement is to the center frequency information of catching filter 13 and send selected digital signals, catches 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 and process, then pass through successively automatic gain control amplifier 3, 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, then send 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth, after this Serial No. is changed through number-mould, form a control voltage Vc, this voltage Vc is transmitted to and catches filter 13 for adjusting the bandwidth of catching filter 13.Radiofrequency signal through front-end wideband low noise amplifier 17 enters when catching filter 13 again, to carry out filtering according to this bandwidth value, then signal enters again demodulating and decoding module 14 through some row amplifications, frequency conversion, filtering after processing, demodulating and decoding module 14 produces a control voltage Vc again, so repeatedly adjustment 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 (1)
1. Digital Television tuner, comprise the front-end wideband low noise amplifier (17), down conversion module (16), the demodulating and decoding module (14) that are consisted of by high pass filter (1), broadband low noise amplifier (2), it is characterized in that: also comprise and catch filter (13), described input of catching filter (13) fetches respectively the I in front-end wideband low noise amplifier (17), demodulating and decoding module (14), down conversion module (16)
2The signal of C controller (10) is caught the amplifier (15) in filter (13) the output termination down conversion module (16);
Catching filter (13) bandwidth and centre frequency is handled as follows;
After demodulating and decoding module (14) receives intermediate-freuqncy signal, bandwidth to intermediate-freuqncy signal is judged, then send 16 numerical sequence signal of an expression intermediate-freuqncy signal bandwidth, after this Serial No. is changed through number-mould, form a control voltage Vc, adjust the bandwidth of catching filter (13);
I
2C controller (10) passes through I behind selected digital TV channel
2The C agreement is to the center frequency information of catching filter (13) and send selected digital signal, catches after filter (13) receives this information, and signal is converted into dc controling level, regulates its centre frequency;
Then, catch filter (13) and according to above-mentioned bandwidth value and center frequency value the signal of inputting is carried out the filtering processing.
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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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| 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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| CN102131068A CN102131068A (en) | 2011-07-20 |
| CN102131068B true CN102131068B (en) | 2013-01-23 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103167254B (en) * | 2013-03-29 | 2016-02-24 | 深圳英盟欣科技有限公司 | High frequency tuner circuit |
Family Cites Families (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 |
| JP2009088618A (en) * | 2007-09-27 | 2009-04-23 | Sanyo Electric Co Ltd | Receiving device |
| 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 |
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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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Address after: 230088 ginkgo Road, hi tech Zone, Anhui, Hefei, 108 Patentee after: HEFEI RADIO COMMUNICATION TECHNOLOGY CO.,LTD. Address before: 230088 ginkgo Road, hi tech Zone, Anhui, Hefei, 108 Patentee before: Hefei radio communication Polytron Technologies Inc. |
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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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