CN104469084A - Device for eliminating same frequency interference of digital TV receiver - Google Patents
Device for eliminating same frequency interference of digital TV receiver Download PDFInfo
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- CN104469084A CN104469084A CN201310428156.5A CN201310428156A CN104469084A CN 104469084 A CN104469084 A CN 104469084A CN 201310428156 A CN201310428156 A CN 201310428156A CN 104469084 A CN104469084 A CN 104469084A
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Abstract
Provided is a device for eliminating same frequency interference of a digital TV receiver. The device comprises a detection and determination module, a same frequency interference elimination module, and a digital automatic gain control module connected in sequence. The detection and determination module is used to detect and determine a same frequency interference signal. The same frequency interference elimination module moves the same frequency interference signal and filters the same frequency interference signal. The digital automatic gain control module restores power of the signal which is removed with same frequency interference to an initial value. The device for eliminating same frequency interference of a digital TV receiver effectively reduces same frequency interference of a simulated same frequency signal on the digital receiver, and signal distortion factor is greatly reduced, and the device occupies little hardware resource and is low in power consumption. The device is suitable for large-scale popularization and application.
Description
Technical field
The invention belongs to consumer electronics field, relate to a kind of digital television receiver co-channel interference cancellation element.
Background technology
Simulated television, with the transmission of vestigial sideband amplitudemodulation mode frequency division multiplexing, is characterized in clear and definite carrier frequency.
Such as television image signal is modulated onto on the carrier wave that frequency is f1, for avoiding the main energetic region of picture signal, again in 8 MHz bandwidth, audio signal is modulated onto frequency and is about on the carrier wave of .f1+6 MHz, and colour subcarrier has a peak of beating at f1+4 MHz place, change along with the difference of pattern colour saturation.And Digital Television is encoded by MPEG 2 transport stream channel to carry out amplitude modulation, phase modulation or amplitude modulation with phase modulation to high frequency carrier and combine, form digital television signal, and amplitude modulation is here balanced amplitude modulation, inhibits carrier component.Thus from spectrum analyzer, the modulated signal frequency spectrum of a digital channel, as the noise floor that is elevated, is evenly laid within whole bandwidth, and without peak in whole restriction bandwidth.
When digital television signal and anolog TV signals transmit in same frequency range, anolog TV signals are superimposed upon in digital signal, there are 3 peaks (wherein 1 meeting is beated) in the signal spectrum that digital television receiver is received, this phenomenon is referred to as simulation co-channel interference in restriction bandwidth range.If do not processed, follow-up signal processing (as balanced, decoding) can be affected, reduce receiver overall performance.
Summary of the invention
To digital television signal co-channel interference for solving analog signal in prior art, cause the technical problem that receiver performance declines, the invention provides a kind of digital television receiver co-channel interference cancellation element.
Digital television receiver co-channel interference cancellation element, comprises the detection judge module, co-channel interference cancellation module and the digital resources obtainment module that are connected successively;
Described detection judge module is used for detection and judges co-channel interference signal;
Co-channel interference signal is moved and filtering by described co-channel interference cancellation module;
Described digital resources obtainment module is recovered moving the signal power after co-channel interference at initial value.
Preferably, first described detection judge module carries out Fourier transform to input signal, transfers time-domain signal to frequency-region signal.
Preferably, the sample frequency of described Fourier transform is 15 megahertzes.
Preferably, co-channel interference signal is moved to zero frequency place by described co-channel interference cancellation module.
Preferably, described co-channel interference cancellation module uses high pass filter to carry out filtering to the signal moved after co-channel interference signal.
Preferably, described high pass filter is single order endless impulse response filter.
Digital television receiver co-channel interference cancellation element of the present invention, effectively reduce simulation homogenous frequency signal to the co-channel interference of digital receiver, signal distortion reduces greatly, and it is few to take hardware resource, low in energy consumption, is applicable to large-scale promotion and uses.
Embodiment
Below provide the present invention's embodiment.
Whether co-channel interference module is divided into 3 parts: 1) detect judge module, for detecting in Received signal strength containing co-channel interference and position.Because co-channel interference amplitude on frequency domain is very large, so Fourier transform (FFT) can be done to input signal, time-domain signal is transformed into analyzing and processing on frequency domain.By the size of more each bin magnitudes value, finding out position and the amplitude of peak value, then peak amplitude is compared with certain thresholding, then thinking co-channel interference as being greater than thresholding, otherwise think to be subject to interchannel noise impact; 2) co-channel interference cancellation module.Signal spectrum is moved in the co-channel interference position first found according to detection module, makes co-channel interference be positioned at zero frequency place, then uses high pass filter filtering co-channel interference, finally move module with inverse frequency spectrum and the frequency spectrum of signal is moved back to original position; 3) digital resources obtainment (AGC).Because the signal amplitude after eliminating co-channel interference can reduce, so the power controlling output signal with AGC, it is made to be stabilized near reference power value.
Due to exist simultaneously image carrier interference and sound carrier interference, so need 2 times elimination processes, and the 2nd secondary the 1st time counter move after carry out again.Because FFT consumes great amount of hardware resources, so detection module is disposable find out peak-peak position (binl) and second largest peak value position (bin2), the data after eliminating co-channel interference to the 1st time are avoided to carry out a FFT again.But this design should be noted that following two problems:
1) because two carrier-in-interference are not mono-tone interference, there is certain bandwidth, so when finding secondary large peak, need window in the position of maximum peak, and find outside window, otherwise the peak abutting against maximum peak side to be thought time large peak, such 2nd elimination process not only does not disappear sound carrier interference, has also damaged useful signal.
2) because the randomness of signal and FFT also exist intrinsic computational accuracy error (as the design adopts 2 048 FFT, under 15 MHz sample frequencys, minimum frequency resolution is about 7.3 kHz), detect according to single result and have comparatively big error, especially the judgement of sound carrier position, so the design adopts the mean value of repeatedly FFT result to detect the position of two peak values.
Adopt single order endless impulse response (IIR) filter as high pass filter in the present embodiment, by adjustment factor, the outer supression of bandwidth sum band is all met the demands.Due to approximately high 8 ~ 10 dB of image carrier signal interference ratio sound carrier signal disturbing, so it is different that the bandwidth sum band of dual stage filter is restrained outward, the 2nd grade of outer supression of band is less than l level.The parameter of the 1st grade of high pass filter is: ao=1, a1=63/64., bo=1, b1=1, and corresponding zero point is 1, and limit is 63/64, and bandwidth is 36.62 kHz; The parameter of the 2nd grade of high pass filter is: a0=1, a1=127/128,6.=l, 6.=1, corresponding zero point is 1, and limit is 127/128, and bandwidth is 18.31 k.Hz.Through many experiments checking, this combined effect is desirable.
Emulation adopts the mixed signal of anolog TV signals and digital television signal.The former is the anolog TV signals that antenna receives, and amplitude is one 50 dBm; The latter is the digital television signal that digital modulator sends, and amplitude is adjustable.By regulating channel simulator to make the amplitude of digital television signal reduce gradually, when being reduced to one 59 dBm, receiver can normally work, then reduces and will produce error code.When modulator uses low bit-rate (4QAM), signal is reduced to one 64 dBm, and receiver still can normally work, then reduces and will produce error code.
By observing the data that logic analyzer is adopted, the peak detected is exactly the position of co-channel interference.To sampling, the mixed signal data obtained make functional simulation, are found by contrast, after the multiple averaging of FFT result, more easily detect image carrier interference and sound carrier interference, especially sound carrier interference.And when detecting by single FFT result, the change in location of secondary maximum peak is relatively more frequent, often make mistakes.
By observing the average power of the steady timer control word excursion of digital AGC and output signal, can judge whether AGC normally works.The variance of control word is 0.006, and the average power of output signal is also very close with reference power.
Above-describedly be only the preferred embodiments of the present invention, described embodiment is also not used to limit scope of patent protection of the present invention, and the therefore equivalent structure change done of every utilization description of the present invention, in like manner all should be included in protection scope of the present invention.
Claims (6)
1. digital television receiver co-channel interference cancellation element, is characterized in that, comprises the detection judge module, co-channel interference cancellation module and the digital resources obtainment module that are connected successively;
Described detection judge module is used for detection and judges co-channel interference signal;
Co-channel interference signal is moved and filtering by described co-channel interference cancellation module;
Described digital resources obtainment module is recovered moving the signal power after co-channel interference at initial value.
2. a digital television receiver co-channel interference cancellation element as claimed in claim 1, it is characterized in that, first described detection judge module carries out Fourier transform to input signal, transfers time-domain signal to frequency-region signal.
3. a digital television receiver co-channel interference cancellation element as claimed in claim 2, it is characterized in that, the sample frequency of described Fourier transform is 15 megahertzes.
4. a digital television receiver co-channel interference cancellation element as claimed in claim 1, it is characterized in that, co-channel interference signal is moved to zero frequency place by described co-channel interference cancellation module.
5. a digital television receiver co-channel interference cancellation element as claimed in claim 1, is characterized in that, described co-channel interference cancellation module uses high pass filter to carry out filtering to the signal moved after co-channel interference signal.
6. a digital television receiver co-channel interference cancellation element as claimed in claim 5, it is characterized in that, described high pass filter is single order endless impulse response filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201310428156.5A CN104469084A (en) | 2013-09-22 | 2013-09-22 | Device for eliminating same frequency interference of digital TV receiver |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310428156.5A CN104469084A (en) | 2013-09-22 | 2013-09-22 | Device for eliminating same frequency interference of digital TV receiver |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106569235A (en) * | 2016-11-17 | 2017-04-19 | 上海卫星工程研究所 | Design method of L-band SAR (synthetic aperture radar) satellite and navigation receiver anti-co-channel interference |
| WO2019010937A1 (en) * | 2017-07-10 | 2019-01-17 | 京东方科技集团股份有限公司 | Anti-noise signal modulation circuit, modulation method, display panel and display device |
| CN110447173A (en) * | 2017-03-31 | 2019-11-12 | 法国大陆汽车公司 | Method for weakening interference caused by intermodulation product |
| CN111983646A (en) * | 2018-12-29 | 2020-11-24 | 上海司南卫星导航技术股份有限公司 | Receiving device, terminal device and computer readable storage medium |
-
2013
- 2013-09-22 CN CN201310428156.5A patent/CN104469084A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106569235A (en) * | 2016-11-17 | 2017-04-19 | 上海卫星工程研究所 | Design method of L-band SAR (synthetic aperture radar) satellite and navigation receiver anti-co-channel interference |
| CN110447173A (en) * | 2017-03-31 | 2019-11-12 | 法国大陆汽车公司 | Method for weakening interference caused by intermodulation product |
| CN110447173B (en) * | 2017-03-31 | 2021-08-13 | 法国大陆汽车公司 | Method for attenuating interference generated by intermodulation products |
| WO2019010937A1 (en) * | 2017-07-10 | 2019-01-17 | 京东方科技集团股份有限公司 | Anti-noise signal modulation circuit, modulation method, display panel and display device |
| US11373563B2 (en) | 2017-07-10 | 2022-06-28 | Boe Technology Group Co., Ltd. | Anti-noise signal modulation circuit, modulation method, display panel and display device |
| CN111983646A (en) * | 2018-12-29 | 2020-11-24 | 上海司南卫星导航技术股份有限公司 | Receiving device, terminal device and computer readable storage medium |
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Application publication date: 20150325 |