CN102176749B - Method and device for automatically selecting audio format of tuner - Google Patents
Method and device for automatically selecting audio format of tuner Download PDFInfo
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- CN102176749B CN102176749B CN 201110025246 CN201110025246A CN102176749B CN 102176749 B CN102176749 B CN 102176749B CN 201110025246 CN201110025246 CN 201110025246 CN 201110025246 A CN201110025246 A CN 201110025246A CN 102176749 B CN102176749 B CN 102176749B
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Abstract
The invention provides a method and device for automatically selecting the audio format of a tuner. A controller sets a video acoustic surface wave filter as a first set bandwidth, and sets the video acoustic surface wave filter as a second set bandwidth according to the condition that the signal strength of a CVBS (composite video broadcast signal) at the central frequency of a first band-pass filter is less than or equal to that at the central frequency of a second band-pass filter, and a video decoder and an audio decoder judge the formats of the received signals respectively; and the controller sets the video acoustic surface wave filter as the second set bandwidth according to the conditions that the signal strength of the CVBS at the central frequency of the first band-pass filter is greater than that at the central frequency of the second band-pass filter and the signal strength at the rear edge of the CVBS is less than or equal to that at a synchronous end, and the video decoder and the audio decoder judge the formats of the received signals respectively. By adopting the method and device provided by the invention, the audio formats output by the tuner can be automatically detected.
Description
Technical field
The present invention relates to tuner, particularly a kind of method and device of in television system, choosing the tuner audio format automatically.
Background technology
The television format signal that uses more widely at present include NTSC (National Television SystemCommittee), line-by-line inversion (Phase Alternating Line, PAL), and SECAM etc.Wherein, ntsc television signal format abbreviates the N system again as, its colourcast standard for being formulated by National Television System Committee (NTSC) December nineteen fifty-two, and two big main branches are NTSC-J and NTSC-US, NTSC-US has another name called NTSC-U/C.
The frame frequency of ntsc television signal format is per second 29.97fps, and scan line is 525, and scan mode is for lining by line scan, and aspect ratio is 4: 3, and resolution is 720x480.Ntsc television signal format has solved colour and the compatible problem of monochrome broadcasting, but ntsc television signal format has the shortcoming of the easy distortion of phase place, color less stable.
Fig. 1 is the sketch map of existing ntsc television system parameters.Letter M refers to monochromatic normal line and field frequency (525/59.94), video bandwidth 4.2MHz, and the video carrier frequency that sound carrier frequency 4.5MHz is above, channel band is wide to be 6MHz.The NTSC form is meant information technology, the monochrome signal of increasing colour.
The NTSC4.43 television format signal is generally used for many standard analogs video tape recorder.Level and vertical sequential (FH, FV) the same with the NTSC-M television format signal.NTSC 4.43 television format signals use the modulation format identical with the PAL television format signal, adopt the color subcarrier of 4.43361875MHz.
What Japan was adopted is the NTSC-J television format signal, and level is the same with the NTSC-M television format signal with vertical sequential.
At 1850s, colourcast was just being planned in West Europe at that time, but the ntsc television signal format of the U.S. itself had many defectives at that time, comprised when the condition of acceptance difference, form and aspect takes place easily shift (colour tone shifting) phenomenon.In order to overcome the shortcoming of ntsc television signal format, European then voluntarily research and development be fit to the color TV form in Europe, be exactly PAL television format signal and SECAM television format signal afterwards.Fig. 2 is the sketch map of existing P AL television system parameter.PAL television format signal and both picture frequencies of SECAM television format signal are all 50Hz, are fit to the 50Hz ac power frequency in Europe itself.
The PAL television format signal is by the moral rule wind root company design of at that time West Germany; The PAL television format signal came out in 1963; BBC then is the TV station that uses the PAL television format signal the earliest; Piloted at its BBC2 channel in 1964,1967 formally begin colored comprehensively broadcasting, and West Germany then began in 1967 to broadcast.International Telecommunication Union formally formally was defined as Recommendation ITU-R BT.470-6, Conventional TelevisionSystems at its publication with the PAL television format signal in 1998.
(French: the implication of SECAM is " transmitting colored in order and storage " to the SECAM television format signal S é quential Couleur Avec M é moire), is succeeded in developing by France in 1966.In signals transmission, the every row of luminance signal transmits, and two color difference signals then transmit line by line successively, promptly with stagger colour contamination that the way in transmission time avoids being produced when transmitting simultaneously and by its chromatic distortion that causes of row.SECAM television format signal characteristics are not to be afraid of interference, and color effect is good, but poor compatibility.The frame frequency of television format signal is per second 25 frames, and scan line is 625 row, and scan mode is interlacing scan, and aspect ratio is 4: 3, and resolution is 720x576.
Because the television format signal that various countries adopted is different, and comprises vision signal and audio signal simultaneously.The vision signal and the audio signal that therefore will correctly solve in the TV signal have its difficulty.In known references, United States Patent (USP) the 6th, 765, No. 621 whether bulletin only detects 4.5MHz place audio signal and exists, but undeclared when existing color subcarrier to be the vision signal at 4.43MHz place, how to judge both difference.
If when a tuner (Tuner) is supported NTSC358-M/BG/DK/I, NTSC443-BG/DK/I, PAL-M, PAL-BG/DK/I and PAL-N form simultaneously; Because of the sound carrier frequency of NTSC358-M/BG/DK/I, NTSC443-BG/DK/I and PAL-M signal at 4.5MHz; And therefore the vision signal color subcarrier of NTSC443-BG/DK/I, PAL-BG/DK/I signal can't be utilized near the signal magnitude of direct relatively 4.5MHz to judge near the signal of being imported of 4.5MHz and be vision signal or audio signal near 4.5MHz.Therefore, choose automatically in the existing television system that method and the device of tuner audio format is real to have necessity of improving.
Summary of the invention
In view of this, the object of the present invention is to provide a kind of method of choosing the tuner audio format automatically, can detect the audio format of tuner output automatically.
The object of the present invention is to provide a kind of device of choosing the tuner audio format automatically, can detect the audio format of tuner output automatically.
A kind of method of choosing the tuner audio format automatically, this method comprises:
The one first setting bandwidth that A, video SAW filter are set according to controller, first intermediate-freuqncy signal that tuner is exported converts video if signal into; The audio sound SAWF is under the control of controller, and first intermediate-freuqncy signal that tuner is exported converts the sound intermediate frequency signal into; Demodulator carries out demodulation to produce a CVBS signal to video if signal under the control of controller, the sound intermediate frequency signal is carried out demodulation to produce one second sound if signal;
The centre frequency that first band pass filter that B, Video Decoder comprise and second band pass filter are set according to controller is carried out filtering to said CVBS signal simultaneously; The centre frequency of said first band pass filter is greater than the centre frequency of said second band pass filter;
C, controller judge said CVBS signal in the signal strength signal intensity at the centre frequency place of first band pass filter whether greater than the signal strength signal intensity of said CVBS signal at the centre frequency place of second band pass filter, if, execution in step D, otherwise execution in step E;
D, controller are controlled first band pass filter and are detected the signal strength signal intensity of CVBS signal at synchronous end and trailing edge place; And whether the signal strength signal intensity of judging said trailing edge place is greater than the signal strength signal intensity of said synchronous end; If then Video Decoder is decoded to the CVBS signal that receives under the control of controller; And judge that its video format is one of them of NTSC443, PAL and SECAM form; Audio decoder is decoded to second sound if signal that receives under the control of controller, and judges that its audio format is one of them of BG, DK and I form; Otherwise execution in step F;
The second setting bandwidth that E, video SAW filter are set according to controller, first intermediate-freuqncy signal that tuner is exported converts video if signal into; Video Decoder is decoded to the CVBS signal that receives once more, and is judged that its video format is one of them of NTSC, PAL-M and PAL-N form under controller control; Audio decoder is decoded to second sound if signal that receives under the control of controller, and judges that its audio format is one of them of M, BG, DK and I form;
The second setting bandwidth that F, video SAW filter are set according to controller, first intermediate-freuqncy signal that tuner is exported converts video if signal into; Video Decoder is decoded to the CVBS signal that receives once more, and is judged that its video format is one of them of NTSC, PAL-M and PAL-N form under controller control; Audio decoder is decoded to second sound if signal that receives under the control of controller, and judges that its audio format is one of them of M and N form.
In the said method, the centre frequency of said first band pass filter is 4.43MHz, and the centre frequency of said second band pass filter is 3.58MHz.
In the said method, the said first setting bandwidth is 5.5MHz, and the said second setting bandwidth is 4.5MHz.
A kind of device of choosing the tuner audio format automatically, this device comprises:
One tuner receives a radiofrequency signal, and under the control of controller, converts said radiofrequency signal into one first intermediate-freuqncy signal, exports first intermediate-freuqncy signal to video SAW filter and audio sound SAWF;
One video SAW filter is set bandwidth according to the first setting bandwidth or second that controller is set, and converts said first intermediate-freuqncy signal into a video if signal, and the output video intermediate-freuqncy signal is to demodulator;
One audio sound SAWF under the control of controller, converts said first intermediate-freuqncy signal into a sound intermediate frequency signal, and the output audio intermediate-freuqncy signal is to demodulator;
One demodulator; Under the control of controller, said video if signal demodulation is produced a CVBS signal, the demodulation of said sound intermediate frequency signal is produced one second sound if signal; Export said CVBS signal to Video Decoder, export said second sound if signal to audio decoder;
One Video Decoder is under the control of controller, to said CVBS signal decoding, to judge the video format of said CVBS signal; Comprise first band pass filter and second band pass filter, the centre frequency that said first band pass filter and said second band pass filter are set according to controller is carried out filtering to said CVBS signal simultaneously, and is exported controller to; The centre frequency of said first band pass filter is greater than the centre frequency of said second band pass filter;
One audio decoder is under the control of controller, to said second sound if signal decoding, to judge the audio format of said second sound if signal;
One controller; At first setting the video SAW filter is the first setting bandwidth; At said CVBS signal when the signal strength signal intensity of the centre frequency of first band pass filter is less than or equal to the signal strength signal intensity of said CVBS signal in the centre frequency of second band pass filter; Setting the video SAW filter is the second setting bandwidth; Control said Video Decoder and judge that the video format of the CVBS that receives once more is one of them of NTSC, PAL-M and PAL-N form, controls said audio decoder and judges that the form of said second sound if signal is one of them of M, BG, DK and I form;
Said controller, is controlled said first band pass filter and is detected the CVBS signal in the signal strength signal intensity at end and trailing edge place synchronously in the signal strength signal intensity of the centre frequency of first band pass filter during greater than the signal strength signal intensity of said CVBS signal in the centre frequency of second band pass filter at said CVBS signal;
Said controller is in the signal strength signal intensity of judging the trailing edge place during greater than the signal strength signal intensity of end synchronously; Control said Video Decoder and judge that the video format of said CVBS is one of them of NTSC443, PAL and SECAM form, control said audio decoder and judge that the audio format of said second sound if signal is one of them of BG, DK and I form;
When said controller is less than or equal to the signal strength signal intensity of synchronous end in the signal strength signal intensity of judging the trailing edge place; Setting said video SAW filter is the second setting bandwidth; Control said Video Decoder and judge that the video format of the CVBS that receives once more is one of them of NTSC, PAL-M and PAL-N form, controls said audio decoder and judges that the audio format of said second sound if signal is one of them of M and N form.
In the said apparatus, the centre frequency of said first band pass filter is 4.43MHz, and the centre frequency of said second band pass filter is 3.58MHz.
In the said apparatus, the said first setting bandwidth is 5.5MHz, and the said second setting bandwidth is 4.5MHz.
Visible by above-mentioned technical scheme; The invention provides a kind of method and device of choosing the tuner audio format automatically; It is the first setting bandwidth that controller is set the video SAW filter; Be less than or equal to its signal strength signal intensity in the centre frequency of second band pass filter according to the CVBS signal in the signal strength signal intensity of the centre frequency of first band pass filter, it is improper to draw the first setting bandwidth, and further setting the video SAW filter is the second setting bandwidth; And then making Video Decoder judge the form of CVBS signal, audio decoder is judged the form of second sound if signal; According to the CVBS signal in the signal strength signal intensity of the centre frequency of first band pass filter greater than its signal strength signal intensity in the centre frequency of second band pass filter; The signal strength signal intensity that further is less than or equal to synchronous end according to the signal strength signal intensity at CVBS signal trailing edge place; The bandwidth settings of confirming the video SAW filter gets improper; Setting the video SAW filter is the second setting bandwidth; And then making Video Decoder judge the form of CVBS signal, audio decoder is judged the form of second sound if signal.Adopt method of the present invention and device, can judge the signal that is in same frequency is vision signal or audio signal, and then detects the audio format of tuner output automatically.
Description of drawings
Fig. 1 is the sketch map of existing NTSC system parameters.
Fig. 2 is the sketch map of existing PAL television system parameter.
Fig. 3 is a kind of structural representation of choosing the device of tuner audio format automatically of the present invention.
Fig. 4 is a kind of flow chart of choosing the method for tuner audio format automatically of the present invention.
Fig. 5 is the sketch map of CVBS signal of the present invention in the signal strength signal intensity at synchronous end and trailing edge place.
Fig. 6 is CVBS signal of the present invention another sketch map in the signal strength signal intensity at synchronous end and trailing edge place.
[main element symbol description]
Audio sound SAWF 330 demodulators 340
Video Decoder 350 audio decoders 360
First band pass filter, 351 second band pass filters 352
Embodiment
For make the object of the invention, technical scheme, and advantage clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, to further explain of the present invention.
The invention relates to a kind of method and device of choosing the tuner audio format automatically, this method and device of choosing the tuner audio format automatically is applied in the television system.
Fig. 3 is a kind of structural representation of choosing the device of tuner audio format automatically of the present invention.The device that the present invention chooses the tuner audio format automatically comprises: a tuner 310, a video SAW filter (Video SAW Filter) 320, one audio sound SAWF (Audio SAW Filter) 330, one demodulator (demodulator) 340, a Video Decoder (Video decoder) 350, one audio decoder (Audiodecoder) 360, an and controller 370.
The bandwidth that video SAW filter 320 is set according to controller 370 converts first intermediate-freuqncy signal into a video if signal (VIF), output video intermediate-freuqncy signal to demodulator 340.Wherein, the bandwidth of said setting can be set bandwidth for the first setting bandwidth or second; Preferably, the first setting bandwidth is 5.5MHz, and the second setting bandwidth is 4.5MHz.
Audio sound SAWF 330 converts first intermediate-freuqncy signal into a sound intermediate frequency signal (SIF), output audio intermediate-freuqncy signal to demodulator 340 under the control of controller 370.
The centre frequency that Video Decoder (Video decoder) 350 sets according to controller 370 is to the CVBS signal decoding, to judge the video format of this CVBS signal.Wherein, Video Decoder 350 comprises one first band pass filter 351 and one second band pass filter 352.First centre frequency that first band pass filter 351 is set according to controller 370 to the CVBS signal filtering that receives, is exported filtered CVBS signal; Simultaneously, second centre frequency that second band pass filter 352 is set according to controller 370 to the CVBS signal filtering that receives, is exported filtered CVBS signal.Wherein, first centre frequency is greater than second centre frequency; In this preferred embodiment, first centre frequency is 4.43MHz, and second centre frequency is 3.58MHz.
The bandwidth that controller 370 is at first set said video SAW filter 320 is the first setting bandwidth; In the signal strength signal intensity of the CVBS signal of first band pass filter 351 output during, control first band pass filter 351 and detect the CVBS signals in the signal strength signal intensity of end (sync tip) and trailing edge place (Back porch) synchronously greater than the signal strength signal intensity of the CVBS signal of second band pass filter, 352 outputs; During greater than the signal strength signal intensity of end synchronously, the CVBS signal that 350 pairs of control of video decoders receive is decoded, and is one of them of NTSC443, PAL and SECAM form to judge video format in the signal strength signal intensity of judging the trailing edge place; The SSIF signal decoding that 360 pairs of control audio decoders receive is one of them of BG, DK and I form to judge audio format.When controller 370 is less than or equal to the signal strength signal intensity of synchronous end in the signal strength signal intensity of judging the trailing edge place; Setting video SAW filter 320 is the second setting bandwidth; The CVBS signal that 350 pairs of control of video decoders receive is once more decoded, and is one of them of NTSC, PAL-M and PAL-N form to judge video format; The SSIF signal decoding that 360 pairs of control audio decoders receive is one of them of M and N form to judge audio format.
When controller 370 is less than or equal to the signal strength signal intensity of CVBS signal of second band pass filter, 352 outputs in the signal strength signal intensity of the CVBS signal of first band pass filter 351 output, sets video SAW filter 320 and be second and set bandwidth; The CVBS signal that 350 pairs of control of video decoders receive is once more decoded, and is one of them of NTSC, PAL-M and PAL-N form to judge video format; The SSIF signal decoding that 360 pairs of control audio decoders receive is one of them of M, BG, DK and I form to judge audio format.
In the present embodiment, the CVBS signal that Video Decoder 350 receives once more is: video SAW filter 320 has changed another CVBS signal that the video if signal that produces after the bandwidth generates after by demodulation.
Fig. 4 is the above-mentioned a kind of corresponding method flow diagram of device of choosing the tuner audio format automatically of the present invention.Combine Fig. 4 at present, method of the present invention is described, specific as follows:
Step 401: the video SAW filter converts first intermediate-freuqncy signal into video if signal according to the first setting bandwidth of setting; The audio sound SAWF converts first intermediate-freuqncy signal into the sound intermediate frequency signal; Demodulator carries out demodulation to produce a CVBS signal to video if signal, and the sound intermediate frequency signal is carried out demodulation to produce one second sound if signal;
In this step; It is one first setting bandwidth that controller 370 is set video SAW filter (Video SAW Filter) 320; Video SAW filter 320 is according to the first setting bandwidth of setting; First intermediate-freuqncy signal (IF) to a tuner 310 outputs is carried out filtering, obtains video if signal; Demodulator 340 is under the control of controller 370, and the demodulated video intermediate-freuqncy signal is to produce a CVBS signal, and output CVBS signal is to Video Decoder 350.Wherein, this first setting bandwidth is 5.5MHz.Simultaneously, audio sound SAWF 330 carries out filtering to first intermediate-freuqncy signal (IF) of tuner 310 outputs under the control of controller 370, obtain the sound intermediate frequency signal; Demodulator 340 is under the control of controller 370, and demodulation sound intermediate frequency signal is exported second sound if signal to audio decoder 360 to produce one second sound if signal (SSIF).
Owing to do not know the form of TV signal, if when at the beginning video SAW filter (SAWFilter) 320 bandwidth settings being 5.5MHz, possibly include audio signal in the signal of output, cause the erroneous judgement of Video Decoder 350 easily.
Step 402: first band pass filter carries out filtering according to first centre frequency that controller is set to the CVBS signal, and second band pass filter carries out filtering according to second centre frequency of controller setting to the CVBS signal simultaneously;
In this step, first band pass filter 351 and second band pass filter 352 carry out bandpass filtering to the CVBS signal that receives simultaneously; Wherein, this first centre frequency is greater than this second centre frequency; Preferably, this first centre frequency is 4.43MHz, and this second centre frequency is 3.58MHz.
Step 403: controller judge the CVBS signal in the signal strength signal intensity at the first centre frequency place whether greater than signal strength signal intensity at the second centre frequency place, if, execution in step 404, otherwise execution in step 408;
Step 404: controller is controlled first band pass filter and is detected the signal strength signal intensity of CVBS signal at synchronous end (sync tip) and trailing edge place (Back porch);
Step 405: controller judge the CVBS signal in the signal strength signal intensity at trailing edge place whether greater than it in the signal strength signal intensity of end synchronously, if, execution in step 406, otherwise execution in step 411;
Step 406: Video Decoder is decoded to this CVBS signal under the control of controller, is one of them of NTSC443, PAL and SECAM form with the video format of judging the CVBS signal.Execution in step 407 afterwards;
Fig. 5 is the sketch map of CVBS signal of the present invention in the signal strength signal intensity at synchronous end and trailing edge place.As shown in Figure 5, the signal strength signal intensity at trailing edge place is greater than the signal strength signal intensity of holding synchronously.
Step 407: audio decoder is decoded to this second sound if signal under the control of controller, is one of them of BG, DK and I form with the audio format of judging second sound if signal; Execution in step 414 afterwards;
Step 408: the second setting bandwidth that the video SAW filter is set according to controller converts first intermediate-freuqncy signal that receives into video if signal;
In step 403; If the signal strength signal intensity of CVBS signal at the centre frequency place of this first band pass filter 351 (4.43MHz) is less than or equal to the signal strength signal intensity of CVBS signal at the centre frequency place of this second band pass filter 352 (3.58MHz), it is one second setting bandwidth that controller 370 resets video SAW filter 320.Preferably, this second setting bandwidth is 4.5MHz.
This moment, to represent the initial bandwidth settings of the video SAW filter 320 in the step 401 be wrong, therefore, the bandwidth of video SAW filter 320 is reset to 4.5MHz, and execution in step 409 afterwards.
Step 409: Video Decoder is under controller control, and the video format of judging the CVBS signal is one of them of NTSC, PAL-M and PAL-N form;
Comprise in this step: step 4091, the video if signal after the change bandwidth of 340 pairs of video SAW filters of demodulator, 320 outputs carries out demodulation, regains another CVBS signal; Step 4092,350 pairs of these another CVBS signals that regain of Video Decoder are decoded, and are one of them of NTSC, PAL-M and PAL-N form with the video format of judging this CVBS signal.
Step 410: audio decoder is decoded to this second sound if signal under the control of controller, is one of them of M, BG, DK and I form with the audio format of judging second sound if signal; Execution in step 414 afterwards;
Step 411: the second setting bandwidth that the video SAW filter is set according to controller converts first intermediate-freuqncy signal that receives into video if signal;
When step 405 judges that the signal strength signal intensity of this CVBS signal at the trailing edge place is less than or equal to the signal strength signal intensity of synchronous end; In step 411; It is this second setting bandwidth (4.5MHz) that controller 370 is set video SAW filter 320; And use 320 pairs of these first intermediate-freuqncy signal filtering of this video SAW filter, producing another CVBS signal, and execution in step 412;
Fig. 6 is the sketch map of above-mentioned another CVBS signal of the present invention in the signal strength signal intensity at synchronous end and trailing edge place.As shown in Figure 6, the signal strength signal intensity at trailing edge place is less than or equal to the signal strength signal intensity of synchronous end.
Step 412: Video Decoder is under controller control, and the video format of judging the CVBS signal is one of them of NTSC, PAL-M and PAL-N form;
Comprise in this step: step 4121, the video if signal after the change bandwidth of 340 pairs of video SAW filters of demodulator, 320 outputs carries out demodulation, regains another CVBS signal; Step 4122,350 pairs of these another CVBS signal decodings that regain of Video Decoder are one of them of NTSC, PAL-M and PAL-N form with the video format of judging this CVBS signal.
Step 413: audio decoder is decoded to this second sound if signal under the control of controller, is one of them of M and N form with the audio format of judging second sound if signal; Execution in step 414 afterwards;
Step 414: finish.
In the above embodiment of the present invention, video encoder can adopt existing method, judges the video format type of decoded signal; Audio coder can adopt existing method, judges the audio format types of decoded signal; No longer the method for judging video format type, the method that reaches the judgement audio format types are given unnecessary details at this.
Can know that by above stated specification the present invention provides a method and a device simply and automatically, can choose the audio format of tuner 310 outputs automatically.When tuner 310 carries out channel scanning; Selecting bandwidth earlier for use is the video SAW filter 320 of 5.5MHz; And the signal of collocation H-sync, use a centre frequency to come detection signal in the intensity of end (sync tip) synchronously with trailing edge (Back porch) as the band pass filter of 4.43MHz.If when near the signal the 4.5MHz was audio signal M/N, then audio signal can be coupled on the CVBS signal, signal can be quite in the synchronous end (sync tip) and the intensity of trailing edge (Back porch) through after the band-pass filter; If near the signal the 4.5MHz is a vision signal; Then can coloured clump (color burst) signal on synchronous end (sync tip); Therefore can be stronger in the detected signal strength signal intensity of trailing edge (Back porch), can detect the audio format of tuner output by this automatically.
The above is merely preferred embodiment of the present invention, and is in order to restriction the present invention, not all within spirit of the present invention and principle, any modification of being made, is equal to replacement, improvement etc., all should be included within the scope that the present invention protects.
Claims (6)
1. a method of choosing the tuner audio format automatically is characterized in that, this method comprises:
The one first setting bandwidth that A, video SAW filter are set according to controller, first intermediate-freuqncy signal that tuner is exported converts video if signal into; The audio sound SAWF is under the control of controller, and first intermediate-freuqncy signal that tuner is exported converts the sound intermediate frequency signal into; Demodulator carries out demodulation to produce a CVBS signal to video if signal under the control of controller, the sound intermediate frequency signal is carried out demodulation to produce one second sound if signal;
The centre frequency that first band pass filter that B, Video Decoder comprise and second band pass filter are set according to controller is carried out filtering to said CVBS signal simultaneously; The centre frequency of said first band pass filter is greater than the centre frequency of said second band pass filter;
C, controller judge said CVBS signal in the signal strength signal intensity at the centre frequency place of first band pass filter whether greater than the signal strength signal intensity of said CVBS signal at the centre frequency place of second band pass filter, if, execution in step D, otherwise execution in step E;
D, controller are controlled first band pass filter and are detected the signal strength signal intensity of CVBS signal at synchronous end and trailing edge place; And whether the signal strength signal intensity of judging said trailing edge place is greater than the signal strength signal intensity of said synchronous end; If then Video Decoder is decoded to the CVBS signal that receives under the control of controller; And judge that its video format is one of them of NTSC443, PAL and SECAM form; Audio decoder is decoded to second sound if signal that receives under the control of controller, and judges that its audio format is one of them of BG, DK and I form; Otherwise execution in step F;
The second setting bandwidth that E, video SAW filter are set according to controller, first intermediate-freuqncy signal that tuner is exported converts video if signal into; Video Decoder is decoded to the CVBS signal that receives once more, and is judged that its video format is one of them of NTSC, PAL-M and PAL-N form under controller control; Audio decoder is decoded to second sound if signal that receives under the control of controller, and judges that its audio format is one of them of M, BG, DK and I form;
The second setting bandwidth that F, video SAW filter are set according to controller, first intermediate-freuqncy signal that tuner is exported converts video if signal into; Video Decoder is decoded to the CVBS signal that receives once more, and is judged that its video format is one of them of NTSC, PAL-M and PAL-N form under controller control; Audio decoder is decoded to second sound if signal that receives under the control of controller, and judges that its audio format is one of them of M and N form.
2. the method for claim 1 is characterized in that, the centre frequency of said first band pass filter is 4.43MHz, and the centre frequency of said second band pass filter is 3.58MHz.
3. the method for claim 1 is characterized in that, the said first setting bandwidth is 5.5MHz, and the said second setting bandwidth is 4.5MHz.
4. a device of choosing the tuner audio format automatically is characterized in that, this device comprises:
One tuner receives a radiofrequency signal, and under the control of controller, converts said radiofrequency signal into one first intermediate-freuqncy signal, exports first intermediate-freuqncy signal to video SAW filter and audio sound SAWF;
One video SAW filter is set bandwidth according to the first setting bandwidth or second that controller is set, and converts said first intermediate-freuqncy signal into a video if signal, and the output video intermediate-freuqncy signal is to demodulator;
One audio sound SAWF under the control of controller, converts said first intermediate-freuqncy signal into a sound intermediate frequency signal, and the output audio intermediate-freuqncy signal is to demodulator;
One demodulator; Under the control of controller, said video if signal demodulation is produced a CVBS signal, the demodulation of said sound intermediate frequency signal is produced one second sound if signal; Export said CVBS signal to Video Decoder, export said second sound if signal to audio decoder;
One Video Decoder is under the control of controller, to said CVBS signal decoding, to judge the video format of said CVBS signal; Comprise first band pass filter and second band pass filter, the centre frequency that said first band pass filter and said second band pass filter are set according to controller is carried out filtering to said CVBS signal simultaneously, and is exported controller to; The centre frequency of said first band pass filter is greater than the centre frequency of said second band pass filter;
One audio decoder is under the control of controller, to said second sound if signal decoding, to judge the audio format of said second sound if signal;
One controller; At first setting the video SAW filter is the first setting bandwidth; At said CVBS signal when the signal strength signal intensity of the centre frequency of first band pass filter is less than or equal to the signal strength signal intensity of said CVBS signal in the centre frequency of second band pass filter; Setting the video SAW filter is the second setting bandwidth; Control said Video Decoder and judge that the video format of the CVBS that receives once more is one of them of NTSC, PAL-M and PAL-N form, controls said audio decoder and judges that the form of said second sound if signal is one of them of M, BG, DK and I form;
Said controller, is controlled said first band pass filter and is detected the CVBS signal in the signal strength signal intensity at end and trailing edge place synchronously in the signal strength signal intensity of the centre frequency of first band pass filter during greater than the signal strength signal intensity of said CVBS signal in the centre frequency of second band pass filter at said CVBS signal;
Said controller is in the signal strength signal intensity of judging the trailing edge place during greater than the signal strength signal intensity of end synchronously; Control said Video Decoder and judge that the video format of said CVBS is one of them of NTSC443, PAL and SECAM form, control said audio decoder and judge that the audio format of said second sound if signal is one of them of BG, DK and I form;
When said controller is less than or equal to the signal strength signal intensity of synchronous end in the signal strength signal intensity of judging the trailing edge place; Setting said video SAW filter is the second setting bandwidth; Control said Video Decoder and judge that the video format of the CVBS that receives once more is one of them of NTSC, PAL-M and PAL-N form, controls said audio decoder and judges that the audio format of said second sound if signal is one of them of M and N form.
5. device as claimed in claim 4 is characterized in that, the centre frequency of said first band pass filter is 4.43MHz, and the centre frequency of said second band pass filter is 3.58MHz.
6. device as claimed in claim 4 is characterized in that, the said first setting bandwidth is 5.5MHz, and the said second setting bandwidth is 4.5MHz.
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| CN 201110025246 CN102176749B (en) | 2011-01-18 | 2011-01-18 | Method and device for automatically selecting audio format of tuner |
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| CN 201110025246 CN102176749B (en) | 2011-01-18 | 2011-01-18 | Method and device for automatically selecting audio format of tuner |
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| CN102176749A CN102176749A (en) | 2011-09-07 |
| CN102176749B true CN102176749B (en) | 2012-11-21 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2162009A (en) * | 1984-07-18 | 1986-01-22 | Alps Electric Co Ltd | A tuner unit |
| CN1131855A (en) * | 1994-11-30 | 1996-09-25 | 三星电子株式会社 | Multi-broadcast channel selection apparatus |
| KR20020071353A (en) * | 2001-03-06 | 2002-09-12 | 엘지전자주식회사 | Method for instituting sound mode of multi-TV |
| EP0724359B1 (en) * | 1995-01-25 | 2002-10-02 | Mitsubishi Denki Kabushiki Kaisha | Automatic tuning apparatus |
| CN1856116A (en) * | 2005-04-26 | 2006-11-01 | 株式会社东芝 | Electronic apparatus and broadcast standard determination method |
-
2011
- 2011-01-18 CN CN 201110025246 patent/CN102176749B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2162009A (en) * | 1984-07-18 | 1986-01-22 | Alps Electric Co Ltd | A tuner unit |
| CN1131855A (en) * | 1994-11-30 | 1996-09-25 | 三星电子株式会社 | Multi-broadcast channel selection apparatus |
| EP0724359B1 (en) * | 1995-01-25 | 2002-10-02 | Mitsubishi Denki Kabushiki Kaisha | Automatic tuning apparatus |
| KR20020071353A (en) * | 2001-03-06 | 2002-09-12 | 엘지전자주식회사 | Method for instituting sound mode of multi-TV |
| CN1856116A (en) * | 2005-04-26 | 2006-11-01 | 株式会社东芝 | Electronic apparatus and broadcast standard determination method |
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| CN102176749A (en) | 2011-09-07 |
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