CN105450954A - High-frequency tuner automatic gain control (AGC) circuit and method - Google Patents
High-frequency tuner automatic gain control (AGC) circuit and method Download PDFInfo
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- CN105450954A CN105450954A CN201410436958.5A CN201410436958A CN105450954A CN 105450954 A CN105450954 A CN 105450954A CN 201410436958 A CN201410436958 A CN 201410436958A CN 105450954 A CN105450954 A CN 105450954A
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Abstract
The invention discloses a high-frequency tuner automatic gain control (AGC) method, which comprises the steps of detecting a minimum average value of an image noise amplitude in an output signal of a high-frequency tuner, and outputting a signal of a duty cycle corresponding to the minimum average value of the image noise amplitude based on the minimum average value of the image noise amplitude, so as to control the gain of the high-frequency tuner. The invention further discloses a high-frequency tuner AGC circuit. The invention reduces the snow noise of television programs and can improve the image quality.
Description
Technical field
The present invention relates to TV technology, particularly relate to a kind of high-frequency tuner automatic gain control circuit and method.
Background technology
Television set received television program all be unable to do without high-frequency tuner, i.e. tuner, traditional tuner receives TV RF signals, and constantly detect the field intensity of TV RF signals, and adjust the gain of high-frequency amplifier, the first intermediate level circuit, the second intermediate level circuit according to field strength classification, to reduce the snowflake of TV programme.But, this way is also unreliable, during the intensity height of in fact RF signal, snowflake noise is not necessarily little, because in the process of RF Signal transmissions, other snowflake noise signal may be introduced, i.e. strong signal+strong snowflake noise, this situation method of traditional detection field intensity can not solve snowflake noise problem.
Foregoing, only for auxiliary understanding technical scheme of the present invention, does not represent and admits that foregoing is prior art.
Summary of the invention
Main purpose of the present invention is to realize carrying out gain control to high-frequency tuner, to solve the snowflake noise problem of TV programme.
For achieving the above object, the invention provides a kind of high-frequency tuner auto gain control method, described high-frequency tuner comprises input radio frequency signal and carries out amplifying the high-frequency amplifier of process, the first intermediate level circuit amplified step by step the signal after described high-frequency amplifier amplifies and the second intermediate level circuit to described radiofrequency signal, and described first intermediate level circuit is become to the decoding circuit of CVBS signal with the second intermediate level circuit signal decoding amplified after process, wherein, described high-frequency tuner auto gain control method comprises:
Step S1, from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit, choose an interface as current adjustment interface;
Step S2, export duty ratio from preset range to described current adjustment interface in the signal of a duty ratio, two other interface exports the signal presetting duty ratio; Wherein, if when two other interface correspondence described exists the signal of controlled final duty ratio, then will be exported the signal of final duty ratio in two other interface described by adjusted interface correspondence;
Step S3, from the digital video signal of described CVBS signal after analog-to-digital conversion, gather image noise amplitude, and the mean value of the described image noise amplitude gathered when calculating the signal obtaining the current duty cycle that described current adjustment interface exports, and circulation performs step S2-S3, until obtain the mean value of the image noise amplitude that the signal of each duty ratio is corresponding in the signal of the duty ratio of preset range;
The mean value of the described image noise amplitude that the signal of step S4, all duty ratios compared in preset range is corresponding, obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value;
Step S5, using the duty ratio corresponding to the mean value of described image noise amplitude minimum for described mean value as the signal of final duty ratio exporting described current adjustment interface to.
Preferably, described high-frequency tuner auto gain control method also comprises:
Choose an interface as current adjustment interface in step S6, two interfaces not being selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit, and perform step S2-S5.
Preferably, described high-frequency tuner auto gain control method also comprises:
Choose another one interface as current adjustment interface in step S7, two interfaces not being selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit, and perform step S2-S5;
Step S8, the corresponding interface be connected to described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit export the signal of final duty ratio.
Preferably, after described step S8, described high-frequency tuner auto gain control method also comprises:
Step S9, circulation perform described step S1-S8; Wherein, described current adjustment interface exports the signal of a duty ratio in the duty ratio of preset range, and two other interface exports the signal of corresponding described final duty ratio.
Preferably, described step S1 is specially and chooses corresponding interface successively as current adjustment interface according to putting in order of described second intermediate level circuit, the first intermediate level circuit and high-frequency amplifier.
Preferably, described step S3 comprises:
Step S31, convert described CVBS signal to digital video signal;
Step S32, from described digital video signal with preset the time interval gather a frame picture, until the picture frame number collected reaches default frame number;
Step S33, each frame picture is divided into the region of predetermined number, from each region, randomly draws a line picture carry out image noise amplitude detection, obtain the image noise amplitude of every a line;
Step S34, the value that to be averaged by the image noise amplitude of each row in each frame picture calculate, and obtain the mean value of the image noise amplitude of each frame picture;
Step S35, the value that to be again averaged by each described mean value of the picture of described default frame number calculate, the mean value of the described image noise amplitude gathered when obtaining the signal of the current duty cycle that described current adjustment interface exports.
In addition, for achieving the above object, the present invention also provides a kind of high-frequency tuner automatic gain control circuit, described high-frequency tuner comprises input radio frequency signal and carries out amplifying the high-frequency amplifier of process, the first intermediate level circuit amplified step by step the signal after described high-frequency amplifier amplifies and the second intermediate level circuit to described radiofrequency signal, and described first intermediate level circuit is become to the decoding circuit of CVBS signal with the second intermediate level circuit signal decoding amplified after process, wherein, described high-frequency tuner automatic gain control circuit comprises:
Interface selecting circuit, for choosing an interface as current adjustment interface from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit;
Gain output control circuit, for exporting the signal of a duty ratio in the duty ratio of preset range to described current adjustment interface, two other interface exports the signal presetting duty ratio; Wherein, if when two other interface correspondence described exists the signal of controlled final duty ratio, then will be exported the signal of final duty ratio in two other interface described by adjusted interface correspondence;
Image noise amplitude analysis circuit, for gathering image noise amplitude from the digital video signal of described CVBS signal after analog-to-digital conversion, and the mean value of the described image noise amplitude gathered when calculating the signal obtaining the current duty cycle that described current adjustment interface exports;
First circulating controling circuit, for controlling described gain output control circuit successively and image noise amplitude analysis circuit carries out cycling, until the mean value of image noise amplitude corresponding to the signal obtaining each duty ratio in the signal of the duty ratio of preset range;
Gain acquisition cuicuit, the mean value of the described image noise amplitude that the signal for comparing all duty ratios in preset range is corresponding, obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value;
Described gain output control circuit, also for using the signal of the duty ratio corresponding to the mean value of described image noise amplitude minimum for described mean value as the signal of final duty ratio exporting described current adjustment interface to.
Preferably, described interface selecting circuit also for: choose an interface in two interfaces be not selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit as current adjustment interface;
Described high-frequency tuner automatic gain control circuit also comprises the second circulating controling circuit, for after interface chosen by interface selecting circuit, control described gain output control circuit, image noise amplitude analysis circuit, the first circulating controling circuit and gain acquisition cuicuit successively and carry out cycling, until gain acquisition cuicuit obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value.
Preferably, described interface selecting circuit also for: choose another one interface in two interfaces be not selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit as current adjustment interface;
Described second circulating controling circuit is also for after interface chosen by interface selecting circuit, perform again and control described gain output control circuit, image noise amplitude analysis circuit, the first circulating controling circuit and gain acquisition cuicuit successively and carry out cycling, until gain acquisition cuicuit obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value;
Described gain output control circuit also for: the corresponding interface be connected to described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit exports the signal of final duty ratio.
Preferably, described interface selecting circuit is specifically for choosing corresponding interface successively as current adjustment interface according to putting in order of described second intermediate level circuit, the first intermediate level circuit and high-frequency amplifier.
Preferably, described image noise amplitude analysis circuit comprises:
A/D converter, for converting described CVBS signal to digital video signal;
Sampling unit, for gathering a frame picture, until the picture frame number collected reaches default frame number with the time interval of presetting from described digital video signal;
Analytic unit, for each frame picture being divided into the region of predetermined number, randomly drawing a line picture and carrying out image noise amplitude detection, obtaining the image noise amplitude of every a line from each region;
First computing unit, for being averaged by the image noise amplitude of each row in each frame picture, value calculates, and obtains the mean value of the image noise amplitude of each frame picture;
Second computing unit, each described mean value for the picture by described default frame number be again averaged value calculate, the mean value of the described image noise amplitude gathered when obtaining the signal of the current duty cycle that described current adjustment interface exports.
The present invention by high-frequency amplifier, an interface is chosen as current adjustment interface in the interface of the first intermediate level circuit and the second intermediate level circuit, two other interface is then inputted to the signal of the duty ratio that fixes, then this current adjustment interface is exported to the signal in preset range, until the signal that in duty ratio in this preset range, each duty ratio is corresponding inputs once, simultaneously, during the signal that each duty ratio is corresponding exports interface to, detect the image noise amplitude in the digital video signal of described CVBS signal after analog-to-digital conversion, and select the signal of duty ratio corresponding to minimum image noise amplitude, this signal is exported to described adjustment interface and amplify control to carry out gain, therefore, when high-frequency tuner is under the control of the signal of duty ratio corresponding to minimum image noise amplitude, the snowflake noise of the picture of televising out is relatively minimum, thus decrease the snowflake of broadcasting pictures, improve the quality of picture.
Accompanying drawing explanation
Fig. 1 is the circuit connection structure schematic diagram of high-frequency tuner of the present invention and its automatic gain control circuit;
Fig. 2 is the circuit structure block diagram of high-frequency tuner automatic gain control circuit one embodiment of the present invention;
Fig. 3 is the circuit structure block diagram of gain output control circuit of the present invention;
Fig. 4 is the circuit connection structure schematic diagram of analog quantity change-over circuit one embodiment of the present invention;
Fig. 5 is the circuit structure block diagram of image noise amplitude analysis circuit of the present invention;
Fig. 6 is the schematic flow sheet of high-frequency tuner auto gain control method first embodiment of the present invention;
Fig. 7 is the schematic flow sheet of high-frequency tuner auto gain control method second embodiment of the present invention;
Fig. 8 is the schematic flow sheet of high-frequency tuner auto gain control method the 3rd embodiment of the present invention;
Fig. 9 is the detailed process schematic diagram of step S6 in high-frequency tuner auto gain control method of the present invention.
The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
As shown in Figure 1, high-frequency tuner 1 of the present invention comprises input radio frequency signal and carries out amplifying the high-frequency amplifier 100 of process to described radiofrequency signal, to the first intermediate level circuit 200 and the second intermediate level circuit 300 that the signal after described high-frequency amplifier 100 amplifies amplifies step by step, and described first intermediate level circuit 200 is become to the decoding circuit 400 of CVBS signal (Composite Video Baseband Signal) with the second intermediate level circuit 300 signal decoding amplified after process, this CVBS signal can output to television image decoding, image displaying circuit, simultaneously, this CVBS signal can also be converted into digital video signal, play for Digital Television.Wherein, high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300 are controlled by gain interface G1, G2, G3, by realizing gain interface G1, G2, G3 input direct-current signal controlling the gain of high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300.
Based on above-mentioned high-frequency tuner 1, the present invention proposes a kind of high-frequency tuner automatic gain control circuit, and in one embodiment, with reference to Fig. 1, described high-frequency tuner automatic gain control circuit comprises:
Interface selecting circuit 10, for choosing an interface as current adjustment interface from the interface be connected with described high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300.
Gain output control circuit 20, for exporting the signal of a duty ratio in the duty ratio of preset range to described current adjustment interface, two other interface exports the signal presetting duty ratio; Wherein, if when two other interface correspondence described exists the signal of controlled final duty ratio, then will be exported the signal of final duty ratio in two other interface described by adjusted interface correspondence.If it is out-of-date to only have an interface to be adjusted in two other interface described, then only export the signal of controlled final duty ratio to this interface, another still exports the signal of default duty ratio; If two interfaces were all adjusted, then two all corresponding signals inputting controlled final duty ratio of interface.
Image noise amplitude analysis circuit 30, for gathering image noise amplitude from the digital video signal of described CVBS signal after analog-to-digital conversion, and the mean value of the described image noise amplitude gathered when calculating the signal obtaining the current duty cycle that described current adjustment interface exports.
First circulating controling circuit 40, for controlling described gain output control circuit 20 successively and image noise amplitude analysis circuit 30 carries out cycling, until the mean value of image noise amplitude corresponding to the signal obtaining each duty ratio in the signal of the duty ratio of preset range.
Gain acquisition cuicuit 50, the mean value of the described image noise amplitude that the signal for comparing all duty ratios in preset range is corresponding, obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value.
Described gain output control circuit 20, also for using the signal of the duty ratio corresponding to the mean value of described image noise amplitude minimum for described mean value as the signal of final duty ratio exporting described current adjustment interface to.
The span of duty ratio is 0-100%, and default duty ratio can select median 50%, can certainly select other values in various degree.In practical application, more accurate in order to ensure the control of high-frequency tuner 1, with obtain as much as possible duty ratio within the scope of 0-100% in the minimum average B configuration value of image noise amplitude, need all to carry out image noise amplitude detection to the duty ratio numerical value within the scope of 0-100%.Suppose that the mean value of the described image noise amplitude that the signal of all duty ratios in preset range is corresponding is respectively B1, B2 ... Bn, then need B1, B2 ... Bn compares, select a wherein minimum value, and using the control signal P of signal corresponding for this value as current adjustment interface.If regulating object is the second intermediate level circuit 300, then this control signal P is inputed to the second intermediate level circuit 300, to regulate its gain.Be understandable that, due to this control signal P control the gain of the second intermediate level circuit 300 time, image noise amplitude in its TV signal exported after amplifying process is minimum, therefore, when using this control signal P to control the gain of the second intermediate level circuit 300, just farthest can reduce the quantity of the snowflake noise of picture when televising.
Circuit of the present invention by interface selecting circuit 10 from high-frequency amplifier 100, an interface is chosen as current adjustment interface in the interface of the first intermediate level circuit 200 and the second intermediate level circuit 300, two other interface is then inputted to the signal of the duty ratio that fixes, then gain output control circuit 20 is passed through to the signal in this current adjustment interface output preset range, until the signal that in duty ratio in this preset range, each duty ratio is corresponding inputs once, simultaneously, by image noise amplitude analysis circuit 30 during the signal that each duty ratio is corresponding exports interface to, detect the image noise amplitude in the digital video signal of described CVBS signal after analog-to-digital conversion, and the signal of duty ratio corresponding to minimum image noise amplitude is obtained by gain acquisition cuicuit 50, this signal is exported to described adjustment interface and amplify control to carry out gain, therefore, when high-frequency tuner 1 is under the control of the signal of duty ratio corresponding to minimum image noise amplitude, the snowflake noise of the picture of televising out is relatively minimum, thus decrease the snowflake of broadcasting pictures, improve the quality of picture.
In conjunction with reference Fig. 2, be understandable that, just to high-frequency amplifier 100 in above-described embodiment, one in first intermediate level circuit 200 and the second intermediate level circuit 300 is carried out gain-adjusted control, with above-described embodiment unlike, in the present embodiment, from high-frequency amplifier 100, choose any two in first intermediate level circuit 200 and the second intermediate level circuit 300 and carry out gain-adjusted control, to improve the precision that gain controls, further reduction TV programme snowflake noise quantity, particularly, based on above-described embodiment, described interface selecting circuit 10 also for: from described high-frequency amplifier 100, an interface is chosen as current adjustment interface in two interfaces be not selected in the interface that first intermediate level circuit 200 is connected with the second intermediate level circuit 300.It should be noted that, described high-frequency tuner automatic gain control circuit comprises the second circulating controling circuit 60, for after interface chosen by interface selecting circuit 10, control described gain output control circuit 20, image noise amplitude analysis circuit 30, first circulating controling circuit 40 and gain acquisition cuicuit 50 successively and carry out cycling, until obtain the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value.
In conjunction with reference Fig. 2, be understandable that, just to high-frequency amplifier 100 in a upper embodiment, any two in first intermediate level circuit 200 and the second intermediate level circuit 300 are carried out gain-adjusted control, with above-described embodiment unlike, the present embodiment is by high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300 all carry out gain-adjusted control, to improve the precision that gain controls further, thus greatly reduce the quantity of TV programme snowflake noise, particularly, based on above-described embodiment, described interface selecting circuit 10 also for from described high-frequency amplifier 100, another one interface is chosen as current adjustment interface in two interfaces be not selected in the interface that first intermediate level circuit 200 is connected with the second intermediate level circuit 300, it should be noted that, described second circulating controling circuit 60 is also for after interface chosen by interface selecting circuit 10, perform again and control described gain output control circuit 20, image noise amplitude analysis circuit 30, first circulating controling circuit 40 and gain acquisition cuicuit 50 successively and carry out cycling, until obtain the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value.In the present embodiment, described gain output control circuit 20 also for: the corresponding interface be connected with the second intermediate level circuit 300 to described high-frequency amplifier 100, first intermediate level circuit 200 exports the signal of final duty ratio.
In addition, it should be noted that, circuit of the present invention is when embody rule, can determine high-frequency tuner 1 export image noise amplitude minimum time high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300 control signal after, analysis can also be carried out on this basis again and determine.
Suppose to input to high-frequency amplifier 100, the control signal of the first intermediate level circuit 200 and the second intermediate level circuit 300 is P1, P2, P3, again to high-frequency amplifier 100, when first intermediate level circuit 200 and the second intermediate level circuit 300 carry out an image noise amplitude analysis, due to the signal P1 determined, P2, P3, so when arranging the signal of default duty ratio, for two not selected interfaces then with the signal P1 determined, P2, two interfaces of the correspondence in P3 control, signal corresponding for each duty ratio within the scope of 0-100% is inputed to current adjustment interface and carries out image noise amplitude analysis by another one equally, to determine the signal of the duty ratio that image noise amplitude minimum average B configuration value is corresponding.Such as, first when the interface G3 that selection is connected with the second intermediate level circuit 300 is current adjustment interface, then to the interface G1 input signal P1 be connected with high-frequency amplifier 100, for the interface G2 input signal P2 that the first intermediate level circuit 200 connects, because signal P1, P2 are compared with the signal of former default duty ratio, the noise amplitude of output image is lower, therefore, when the signal of analysis second intermediate level circuit 300, the result drawn is more accurate, thus greatly reduces the snowflake of television image.
Be understandable that, when choosing that in the middle of the second intermediate level circuit 300, first intermediate level circuit 200 and high-frequency amplifier 100, which is as current adjustment interface, it can be random selecting, also can be in a certain order or rule, based on above-described embodiment, the precision that the present embodiment controls to improve gain, described interface selecting circuit 10 is specifically for choosing corresponding interface successively as current adjustment interface according to described second intermediate level circuit 300, first intermediate level circuit 200 and putting in order of high-frequency amplifier 100.It should be noted that, due to high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300 amplify the radiofrequency signal of input successively, thus, if first regulate the gain of high-frequency amplifier 100 or the first intermediate level circuit 200 to reduce snowflake noise, although so by regulating high-frequency amplifier 100 or the noise of the first intermediate level circuit 200 to original signal to reduce, but may be exaggerated again after the second intermediate level circuit 300, and adopt the mode of inverted order successively to the second intermediate level circuit 300, first intermediate level circuit 200 and high-frequency amplifier 100 carry out gain-adjusted, just can avoid this problem, make control more accurate.
Particularly, in conjunction with reference Fig. 3 and Fig. 4, above-mentioned gain output control circuit 20 comprises signal generating circuit 21, analog quantity change-over circuit 22 and signal control circuit 23, wherein,
Signal generating circuit 21, for generating the PWM pulse-width signal of any duty ratio under the control of signal control circuit 23, wherein the span of duty ratio is 0-100%.
Analog quantity change-over circuit 22, for described PWM pulse width modulated signal conversion being become direct current signal under the control of signal control circuit 23, to export described gain interface G1, G2, G3 to.
Wherein, described analog quantity change-over circuit 22 comprises the first resistance R1, the second resistance R2, the 3rd resistance R3, the first electric capacity C1, the second electric capacity C2, the 3rd electric capacity C3, described first resistance R1 is connected with the first output L1 of described signal generating circuit 21, the other end of described first resistance R1 through described first electric capacity C1 to ground; Described second resistance R2 is connected with the second output L2 of described signal generating circuit 21, the other end of described second resistance R2 through described second electric capacity C2 to ground; Described 3rd resistance R3 is connected with the 3rd output L3 of described signal generating circuit 21, the other end of described 3rd resistance R3 through described 3rd electric capacity C3 to ground.Wherein, the gain interface G1 be connected with described high-frequency amplifier 100 is connected with the common port of described first resistance R1 and the first electric capacity C1; The gain interface G2 be connected with described first intermediate level circuit 200 is connected with the common port of described second resistance R2 and the second electric capacity C2; The gain interface G3 be connected with described second intermediate level circuit 300 is connected with the common port of described 3rd resistance R3 and the 3rd electric capacity C3.
Particularly, in conjunction with reference Fig. 5, above-mentioned image noise amplitude analysis circuit 30 comprises:
A/D converter 31, for converting described CVBS signal to digital video signal;
Sampling unit 32, for gathering a frame picture, until the picture frame number collected reaches default frame number with the time interval of presetting from described digital video signal;
Analytic unit 33, for each frame picture being divided into the region of predetermined number, randomly drawing a line picture and carrying out image noise amplitude detection, obtaining the image noise amplitude of every a line from each region;
First computing unit 34, for being averaged by the image noise amplitude of each row in each frame picture, value calculates, and obtains the mean value of the image noise amplitude of each frame picture;
Second computing unit 35, each described mean value for the picture by described default frame number be again averaged value calculate, the mean value of the described image noise amplitude gathered when obtaining the signal of the current duty cycle that described current adjustment interface exports.
Every 25 behavior one frames or a picture in television image, in the present embodiment, every picture can be divided into 5 regions, 1 row is randomly drawed from each region, or subregion does not directly evenly extract 5 row from top to bottom in every picture, and estimate the noise amplitude value of often going, then the value that this 5 row noise amplitude is averaged calculates, to obtain mean value A1, after time delay preset time T (such as: T=1 second), A2 is calculated with same method, again after time delay T, A3 is calculated with same method, and then to A1, A2, A3 be averaged value calculate, to obtain mean value B.Wherein, the evaluation method of image noise amplitude value can adopt following scheme: because picture noise is all occur with the form of spot in television image, and frequency is between the 2-3MHz in the middle of video frequency domain, also relatively other signal is high for amplitude, therefore inside digital video signal, finds out brightness ratio higher and occur many pulses, it is exactly speckle noise signal, this number of pulses is more, and noise amplitude value is higher, can estimate the noise amplitude value of often going according to this.
The circuit theory of high-frequency tuner automatic gain control circuit of the present invention is as follows:
High-frequency tuner 1, the RF signal that RF signal is input to television set successively after high-frequency amplifier 100, first intermediate level circuit 200, second intermediate level circuit 300 amplifies, demodulates the full television video frequency signal of CVBS in high-frequency tuner 1 inside.Wherein, the signal generating circuit 21 in gain output control circuit 20 is connected with gain interface G1, G2, G3 by analog quantity change-over circuit 22, to export the gain that control signal controls high-frequency amplifier 100, first intermediate level circuit 200, second intermediate level circuit 300.Suppose that signal generating circuit 21 generates pulse-width signal PWM1, PWM2, PWM3 signal of corresponding gain interface G1, G2, G3 under the control of signal control circuit 23, by the integrating circuit that electric capacity and resistance form, i.e. described analog quantity change-over circuit 22, after carrying out filtering process, eliminate pulse signal, become DC control signal, input to gain interface G1, G2, G3, to regulate the gain of high-frequency amplifier 100, first intermediate level circuit 200, second intermediate level circuit 300.It should be noted that, in the middle of the practical application of television set, this DC control signal is generally between 0-3.3V.
Based on foregoing circuit, the invention provides a kind of high-frequency tuner auto gain control method.
With reference to Fig. 6, and combine referring to figs. 1 through Fig. 5, in one embodiment, described high-frequency tuner auto gain control method comprises:
Step S1, from the interface be connected with described high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300, choose an interface as current adjustment interface.
Be understandable that, when choosing that in the middle of the second intermediate level circuit 300, first intermediate level circuit 200 and high-frequency amplifier 100, which is as current adjustment interface, it can be random selecting, also can be in a certain order or rule, based on this embodiment, in order to improve the precision that gain controls, described step S1 is specially and chooses corresponding interface successively as current adjustment interface according to described second intermediate level circuit 300, first intermediate level circuit 200 and putting in order of high-frequency amplifier 100.It should be noted that, due to high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300 amplify the radiofrequency signal of input successively, thus, if first regulate the gain of high-frequency amplifier 100 or the first intermediate level circuit 200 to reduce snowflake noise, although so high-frequency amplifier 100 or the noise of the first intermediate level circuit 200 to original signal reduce, but can be exaggerated again after the second intermediate level circuit 300, and adopt the mode of inverted order successively to the second intermediate level circuit 300, first intermediate level circuit 200 and high-frequency amplifier 100 carry out gain-adjusted, just can avoid this problem, make control more accurate.
Step S2, export duty ratio from preset range to described current adjustment interface in the signal of a duty ratio, two other interface exports the signal presetting duty ratio; Wherein, if when two other interface correspondence described exists the signal of controlled final duty ratio, then will be exported the signal of final duty ratio in two other interface described by adjusted interface correspondence.If it is out-of-date to only have an interface to be adjusted in two other interface described, then only export the signal of controlled final duty ratio to this interface, another still exports the signal of default duty ratio; If two interfaces were all adjusted, then two all corresponding signals inputting controlled final duty ratio of interface.The span of duty ratio is 0-100%, and default duty ratio can select median 50%, can certainly select other values in various degree.In practical application, more accurate in order to ensure the control of high-frequency tuner 1, with obtain as much as possible duty ratio within the scope of 0-100% in the minimum average B configuration value of image noise amplitude, need all to carry out image noise amplitude detection to the duty ratio numerical value within the scope of 0-100%.
Step S3, from the digital video signal of described CVBS signal after analog-to-digital conversion, gather image noise amplitude, and the mean value of the described image noise amplitude gathered when calculating the signal obtaining the current duty cycle that described current adjustment interface exports, and circulation performs step S2-S3, until obtain the mean value of the image noise amplitude that the signal of each duty ratio is corresponding in the signal of the duty ratio of preset range.
Wherein, in conjunction with reference Fig. 9, described step S3 comprises:
Step S31, convert described CVBS signal to digital video signal;
Step S32, from described digital video signal with preset the time interval gather a frame picture, until the picture frame number collected reaches default frame number;
Step S33, each frame picture is divided into the region of predetermined number, from each region, randomly draws a line picture carry out image noise amplitude detection, obtain the image noise amplitude of every a line;
Step S34, the value that to be averaged by the image noise amplitude of each row in each frame picture calculate, and obtain the mean value of the image noise amplitude of each frame picture;
Step S35, the value that to be again averaged by each described mean value of the picture of described default frame number calculate, the mean value of the described image noise amplitude gathered when obtaining the signal of the current duty cycle that described current adjustment interface exports.
It should be noted that, step S33 and step S32 synchronously carry out, and namely each frame picture are divided into the region of predetermined number after having gathered a frame picture; Can certainly be after execution of step S32 execution step S33, after namely having gathered the picture of default frame number, then go to the region each frame picture being divided into predetermined number.In fact, every 25 behavior one frames or a picture in television image, in the present embodiment, every picture can be divided into 5 regions, 1 row is randomly drawed from each region, or subregion does not directly evenly extract 5 row from top to bottom in every picture, and estimate the noise amplitude value of often going, then the value that this 5 row noise amplitude is averaged calculates, to obtain mean value A1, after time delay preset time T (such as: T=1 second), A2 is calculated with same method, again after time delay T, A3 is calculated with same method, and then to A1, A2, A3 be averaged value calculate, to obtain mean value B.Wherein, the evaluation method of image noise amplitude value can adopt following scheme: because picture noise is all occur with the form of spot in television image, and frequency is between the 2-3MHz in the middle of video frequency domain, also relatively other signal is high for amplitude, therefore inside digital video signal, finds out brightness ratio higher and occur many pulses, it is exactly speckle noise signal, this number of pulses is more, and noise amplitude value is higher, can estimate the noise amplitude value of often going according to this.
The mean value of the described image noise amplitude that the signal of step S4, all duty ratios compared in preset range is corresponding, obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value.
Suppose that the mean value of the described image noise amplitude that the signal of all duty ratios in preset range is corresponding is respectively B1, B2 ... Bn, then need B1, B2 ... Bn compares, select a wherein minimum value, and using the control signal P of signal corresponding for this value as current adjustment interface.If regulating object is the second intermediate level circuit 300, then this control signal P is inputed to the second intermediate level circuit 300, to regulate its gain.
Step S5, using the duty ratio corresponding to the mean value of described image noise amplitude minimum for described mean value as the signal of final duty ratio exporting described current adjustment interface to.
Be understandable that, due to this control signal P control the gain of the second intermediate level circuit 300 time, image noise amplitude in its TV signal exported after amplifying process is minimum, therefore, when using this control signal P to control the gain of the second intermediate level circuit 300, just farthest can reduce the quantity of the snowflake noise of picture when televising.
The inventive method by from high-frequency amplifier 100, an interface is chosen as current adjustment interface in the interface of the first intermediate level circuit 200 and the second intermediate level circuit 300, two other interface is then inputted to the signal of the duty ratio that fixes, then this current adjustment interface is exported to the signal in preset range, until the signal that in duty ratio in this preset range, each duty ratio is corresponding inputs once, simultaneously, during the signal that each duty ratio is corresponding exports interface to, detect the image noise amplitude in the digital video signal of described CVBS signal after analog-to-digital conversion, and select the signal of duty ratio corresponding to minimum image noise amplitude, this signal is exported to described adjustment interface and amplify control to carry out gain, therefore, when high-frequency tuner 1 is under the control of the signal of duty ratio corresponding to minimum image noise amplitude, the snowflake noise of the picture of televising out is relatively minimum, thus decrease the snowflake of broadcasting pictures, improve the quality of picture.
Be understandable that, just to high-frequency amplifier 100 in above-described embodiment, one in first intermediate level circuit 200 and the second intermediate level circuit 300 is carried out gain-adjusted control, with above-described embodiment unlike, in the present embodiment, from high-frequency amplifier 100, choose any two in first intermediate level circuit 200 and the second intermediate level circuit 300 and carry out gain-adjusted control, to improve the precision that gain controls, further reduction TV programme snowflake noise quantity, particularly, in conjunction with reference Fig. 7, based on above-described embodiment, the described high-frequency tuner auto gain control method of the present embodiment also comprises:
Choose an interface as current adjustment interface in step S6, two interfaces not being selected from the interface be connected with described high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300, and perform step S2-S5.
Be understandable that, just to high-frequency amplifier 100 in a upper embodiment, any two in first intermediate level circuit 200 and the second intermediate level circuit 300 are carried out gain-adjusted control, with above-described embodiment unlike, the present embodiment is by high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300 all carry out gain-adjusted control, to improve the precision that gain controls further, thus greatly reduce the quantity of TV programme snowflake noise, particularly, in conjunction with reference Fig. 8, based on above-described embodiment, the described high-frequency tuner auto gain control method of the present embodiment also comprises:
Choose another one interface as current adjustment interface in step S7, two interfaces not being selected from the interface be connected with described high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300, and perform step S2-S5;
Step S8, the corresponding interface be connected with the second intermediate level circuit 300 to described high-frequency amplifier 100, first intermediate level circuit 200 export the signal of final duty ratio.
Based on above-described embodiment, in order to improve the precision of high-frequency tuner 1 automatic growth control, reduce snowflake noise, the present embodiment is when determining the signal of final duty ratio of the interface that high-frequency amplifier 100, first intermediate level circuit 200 is connected with the second intermediate level circuit 300, again an image noise amplitude analysis is carried out, to obtain more high-precision control signal to high-frequency amplifier 100, first intermediate level circuit 200 and the second intermediate level circuit 300.
In conjunction with reference to Fig. 6 to Fig. 9, be understandable that, after the described step S8 of execution, described high-frequency tuner auto gain control method also comprises:
Step S9, circulation perform described step S1-S8; Wherein, described current adjustment interface exports the signal of a duty ratio in the duty ratio of preset range, and two other interface exports the signal of corresponding described final duty ratio.
Suppose to input to high-frequency amplifier 100, the control signal of the first intermediate level circuit 200 and the second intermediate level circuit 300 is P1, P2, P3, again to high-frequency amplifier 100, when first intermediate level circuit 200 and the second intermediate level circuit 300 carry out an image noise amplitude analysis, due to the signal P1 determined, P2, P3, so when arranging the signal of default duty ratio, for two not selected interfaces then with the signal P1 determined, P2, two interfaces of the correspondence in P3 control, signal corresponding for each duty ratio within the scope of 0-100% is inputed to current adjustment interface and carries out image noise amplitude analysis by another one equally, to determine the signal of the duty ratio that image noise amplitude minimum average B configuration value is corresponding.Such as, first when the interface G3 that selection is connected with the second intermediate level circuit 300 is current adjustment interface, then to the interface G1 input signal P1 be connected with high-frequency amplifier 100, for the interface G2 input signal P2 that the first intermediate level circuit 200 connects, because signal P1, P2 are compared with presetting the signal of duty ratio in former step S1-S8, the noise amplitude of output image is lower, therefore, when the signal of analysis second intermediate level circuit 300, the result drawn is more accurate, thus greatly reduces the snowflake of television image.
These are only the preferred embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize specification of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (11)
1. a high-frequency tuner auto gain control method, described high-frequency tuner comprises input radio frequency signal and carries out amplifying the high-frequency amplifier of process, the first intermediate level circuit amplified step by step the signal after described high-frequency amplifier amplifies and the second intermediate level circuit to described radiofrequency signal, and described first intermediate level circuit is become to the decoding circuit of CVBS signal with the second intermediate level circuit signal decoding amplified after process, it is characterized in that, described high-frequency tuner auto gain control method comprises:
Step S1, from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit, choose an interface as current adjustment interface;
Step S2, export duty ratio from preset range to described current adjustment interface in the signal of a duty ratio, two other interface exports the signal presetting duty ratio; Wherein, if when two other interface correspondence described exists the signal of controlled final duty ratio, then will be exported the signal of final duty ratio in two other interface described by adjusted interface correspondence;
Step S3, from the digital video signal of described CVBS signal after analog-to-digital conversion, gather image noise amplitude, and the mean value of the described image noise amplitude gathered when calculating the signal obtaining the current duty cycle that described current adjustment interface exports, and circulation performs step S2-S3, until obtain the mean value of the image noise amplitude that the signal of each duty ratio is corresponding in the signal of the duty ratio of preset range;
The mean value of the described image noise amplitude that the signal of step S4, all duty ratios compared in preset range is corresponding, obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value;
Step S5, using the duty ratio corresponding to the mean value of described image noise amplitude minimum for described mean value as the signal of final duty ratio exporting described current adjustment interface to.
2. high-frequency tuner auto gain control method as claimed in claim 1, it is characterized in that, described high-frequency tuner auto gain control method also comprises:
Choose an interface as current adjustment interface in step S6, two interfaces not being selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit, and perform step S2-S5.
3. high-frequency tuner auto gain control method as claimed in claim 2, it is characterized in that, described high-frequency tuner auto gain control method also comprises:
Choose another one interface as current adjustment interface in step S7, two interfaces not being selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit, and perform step S2-S5;
Step S8, the corresponding interface be connected to described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit export the signal of final duty ratio.
4. high-frequency tuner auto gain control method as claimed in claim 3, it is characterized in that, after described step S8, described high-frequency tuner auto gain control method also comprises:
Step S9, circulation perform described step S1-S8; Wherein, described current adjustment interface exports the signal of a duty ratio in the duty ratio of preset range, and two other interface exports the signal of corresponding described final duty ratio.
5. the high-frequency tuner auto gain control method as described in any one of claim 1-4, it is characterized in that, described step S1 is specially and chooses corresponding interface successively as current adjustment interface according to putting in order of described second intermediate level circuit, the first intermediate level circuit and high-frequency amplifier.
6. high-frequency tuner auto gain control method as claimed in claim 5, it is characterized in that, described step S3 comprises:
Step S31, convert described CVBS signal to digital video signal;
Step S32, from described digital video signal with preset the time interval gather a frame picture, until the picture frame number collected reaches default frame number;
Step S33, each frame picture is divided into the region of predetermined number, from each region, randomly draws a line picture carry out image noise amplitude detection, obtain the image noise amplitude of every a line;
Step S34, the value that to be averaged by the image noise amplitude of each row in each frame picture calculate, and obtain the mean value of the image noise amplitude of each frame picture;
Step S35, the value that to be again averaged by each described mean value of the picture of described default frame number calculate, the mean value of the described image noise amplitude gathered when obtaining the signal of the current duty cycle that described current adjustment interface exports.
7. a high-frequency tuner automatic gain control circuit, described high-frequency tuner comprises input radio frequency signal and carries out amplifying the high-frequency amplifier of process, the first intermediate level circuit amplified step by step the signal after described high-frequency amplifier amplifies and the second intermediate level circuit to described radiofrequency signal, and described first intermediate level circuit is become to the decoding circuit of CVBS signal with the second intermediate level circuit signal decoding amplified after process, it is characterized in that, described high-frequency tuner automatic gain control circuit comprises:
Interface selecting circuit, for choosing an interface as current adjustment interface from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit;
Gain output control circuit, for exporting the signal of a duty ratio in the duty ratio of preset range to described current adjustment interface, two other interface exports the signal presetting duty ratio; Wherein, if when two other interface correspondence described exists the signal of controlled final duty ratio, then will be exported the signal of final duty ratio in two other interface described by adjusted interface correspondence;
Image noise amplitude analysis circuit, for gathering image noise amplitude from the digital video signal of described CVBS signal after analog-to-digital conversion, and the mean value of the described image noise amplitude gathered when calculating the signal obtaining the current duty cycle that described current adjustment interface exports;
First circulating controling circuit, for controlling described gain output control circuit successively and image noise amplitude analysis circuit carries out cycling, until the mean value of image noise amplitude corresponding to the signal obtaining each duty ratio in the signal of the duty ratio of preset range;
Gain acquisition cuicuit, the mean value of the described image noise amplitude that the signal for comparing all duty ratios in preset range is corresponding, obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value;
Described gain output control circuit, also for using the signal of the duty ratio corresponding to the mean value of described image noise amplitude minimum for described mean value as the signal of final duty ratio exporting described current adjustment interface to.
8. high-frequency tuner automatic gain control circuit as claimed in claim 7, it is characterized in that, described interface selecting circuit also for: choose an interface in two interfaces be not selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit as current adjustment interface;
Described high-frequency tuner automatic gain control circuit also comprises the second circulating controling circuit, for after interface chosen by interface selecting circuit, control described gain output control circuit, image noise amplitude analysis circuit, the first circulating controling circuit and gain acquisition cuicuit successively and carry out cycling, until gain acquisition cuicuit obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value.
9. high-frequency tuner automatic gain control circuit as claimed in claim 8, it is characterized in that, described interface selecting circuit also for: choose another one interface in two interfaces be not selected from the interface be connected with described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit as current adjustment interface;
Described second circulating controling circuit is also for after interface chosen by interface selecting circuit, perform again and control described gain output control circuit, image noise amplitude analysis circuit, the first circulating controling circuit and gain acquisition cuicuit successively and carry out cycling, until gain acquisition cuicuit obtains the signal of the duty ratio corresponding to mean value of the minimum described image noise amplitude of mean value;
Described gain output control circuit also for: the corresponding interface be connected to described high-frequency amplifier, the first intermediate level circuit and the second intermediate level circuit exports the signal of final duty ratio.
10. the high-frequency tuner automatic gain control circuit as described in any one of claim 7-9, it is characterized in that, described interface selecting circuit is specifically for choosing corresponding interface successively as current adjustment interface according to putting in order of described second intermediate level circuit, the first intermediate level circuit and high-frequency amplifier.
11. high-frequency tuner automatic gain control circuits as claimed in claim 10, it is characterized in that, described image noise amplitude analysis circuit comprises:
A/D converter, for converting described CVBS signal to digital video signal;
Sampling unit, for gathering a frame picture, until the picture frame number collected reaches default frame number with the time interval of presetting from described digital video signal;
Analytic unit, for each frame picture being divided into the region of predetermined number, randomly drawing a line picture and carrying out image noise amplitude detection, obtaining the image noise amplitude of every a line from each region;
First computing unit, for being averaged by the image noise amplitude of each row in each frame picture, value calculates, and obtains the mean value of the image noise amplitude of each frame picture;
Second computing unit, each described mean value for the picture by described default frame number be again averaged value calculate, the mean value of the described image noise amplitude gathered when obtaining the signal of the current duty cycle that described current adjustment interface exports.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106961565A (en) * | 2017-03-17 | 2017-07-18 | 安徽波维电子科技有限公司 | A kind of tuner of the intelligent information prompting based on DSP single-chip microcomputers |
| CN109033389A (en) * | 2018-07-30 | 2018-12-18 | 中国电子科技集团公司第五十四研究所 | A kind of spectrum monitoring data processing platform (DPP) in knowledge based library |
| CN109788355A (en) * | 2018-12-18 | 2019-05-21 | 深圳市纽格力科技有限公司 | Set-top box and method based on live signal adjustment parameter |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2562506Y (en) * | 2002-11-29 | 2003-07-23 | 潘荣华 | Column style C waveband digit tuner |
| WO2007122771A1 (en) * | 2006-04-24 | 2007-11-01 | Niigata Seimitsu Co., Ltd. | Automatic gain controlled circuit and low noise amplifier circuit |
| CN201075397Y (en) * | 2007-08-29 | 2008-06-18 | 郴州高斯贝尔数码科技有限公司 | C waveband double local oscillator multi-leaving down converter |
| JP2010004286A (en) * | 2008-06-19 | 2010-01-07 | Sharp Corp | High-frequency receiver, broadcast receiver, and gain control method of high-frequency receiver |
| JP2010114561A (en) * | 2008-11-05 | 2010-05-20 | Alps Electric Co Ltd | Receiving circuit |
-
2014
- 2014-08-29 CN CN201410436958.5A patent/CN105450954B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2562506Y (en) * | 2002-11-29 | 2003-07-23 | 潘荣华 | Column style C waveband digit tuner |
| WO2007122771A1 (en) * | 2006-04-24 | 2007-11-01 | Niigata Seimitsu Co., Ltd. | Automatic gain controlled circuit and low noise amplifier circuit |
| CN201075397Y (en) * | 2007-08-29 | 2008-06-18 | 郴州高斯贝尔数码科技有限公司 | C waveband double local oscillator multi-leaving down converter |
| JP2010004286A (en) * | 2008-06-19 | 2010-01-07 | Sharp Corp | High-frequency receiver, broadcast receiver, and gain control method of high-frequency receiver |
| JP2010114561A (en) * | 2008-11-05 | 2010-05-20 | Alps Electric Co Ltd | Receiving circuit |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106961565A (en) * | 2017-03-17 | 2017-07-18 | 安徽波维电子科技有限公司 | A kind of tuner of the intelligent information prompting based on DSP single-chip microcomputers |
| CN109033389A (en) * | 2018-07-30 | 2018-12-18 | 中国电子科技集团公司第五十四研究所 | A kind of spectrum monitoring data processing platform (DPP) in knowledge based library |
| CN109788355A (en) * | 2018-12-18 | 2019-05-21 | 深圳市纽格力科技有限公司 | Set-top box and method based on live signal adjustment parameter |
| CN109788355B (en) * | 2018-12-18 | 2021-03-30 | 深圳市纽格力科技有限公司 | Set top box and method for adjusting parameters based on real-time signals |
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