CN107197183B - Method for adjusting gain and method and device for adjusting offset - Google Patents
Method for adjusting gain and method and device for adjusting offset Download PDFInfo
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- CN107197183B CN107197183B CN201710229827.3A CN201710229827A CN107197183B CN 107197183 B CN107197183 B CN 107197183B CN 201710229827 A CN201710229827 A CN 201710229827A CN 107197183 B CN107197183 B CN 107197183B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/52—Automatic gain control
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
Abstract
The invention discloses a method for adjusting gain and a method and a device for adjusting offset, and belongs to the field of communication. The method for adjusting the gain comprises the following steps: inputting a square wave signal to an analog-to-digital conversion module during the field synchronization period of the analog video signal, wherein the amplitude of the square wave signal is smaller than the maximum amplitude of the analog video signal; and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the gain of the analog-to-digital conversion module. The method for adjusting the offset comprises the following steps: inputting an analog video signal to an analog-to-digital conversion module during a field synchronization period of the analog video signal; and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the offset of the analog-to-digital conversion module. The invention can avoid the phenomenon that the colors of the picture deviate.
Description
Technical Field
The present invention relates to the field of communications, and in particular, to a method for adjusting gain, a method for adjusting offset, and an apparatus thereof.
Background
The television is an important device for people to enjoy leisure and entertainment in the home, and is one of the home appliances with the highest frequency of use in the home. The video signal received by the tv is often an Analog signal, so the tv needs to convert the Analog signal into a Digital signal through an Analog-to-Digital Converter (ADC), and then play the Digital signal through a liquid crystal display (lcd) or an Organic Light-Emitting Diode (OLED) display to obtain a video image.
The television sets a gain and an offset for the ADC when being started, and the ADC converts an analog signal received by the television into a digital signal according to the gain and the offset. The ADC can generate heat when the television is played for a long time, the ADC obtains a digital signal through conversion according to the gain and the offset which are set when the television is started, and the phenomenon that the color of a video picture deviates can occur when the television plays the digital signal.
Disclosure of Invention
In order to avoid the phenomenon of color deviation of a video picture, the invention provides a method for adjusting gain, a method for adjusting offset and a device. The technical scheme is as follows:
in a first aspect, the present invention provides a method for adjusting a gain of an analog-to-digital conversion module in a television, the method comprising:
inputting a square wave signal to an analog-to-digital conversion module during the field synchronization period of the analog video signal, wherein the amplitude of the square wave signal is smaller than the maximum amplitude of the analog video signal;
and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the gain of the analog-to-digital conversion module.
Optionally, if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range, adjusting the gain of the analog-to-digital conversion module specifically includes:
if the average value of the digital video signals is smaller than the lower limit value of the preset range, increasing the gain of the analog-digital conversion module;
and if the average value of the digital video signals is larger than the upper limit value of the preset range, reducing the gain of the analog-digital conversion module.
In a second aspect, the present invention provides a method for adjusting an offset of an analog-to-digital conversion module in a television, the method comprising:
inputting an analog video signal to an analog-to-digital conversion module during a field synchronization period of the analog video signal;
and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the offset of the analog-to-digital conversion module.
Optionally, if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range, adjusting the offset of the analog-to-digital conversion module specifically includes:
if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is smaller than the lower limit value of the preset range, increasing the offset of the analog-to-digital conversion module;
and if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is larger than the upper limit value of the preset range, reducing the offset of the analog-to-digital conversion module.
In a third aspect, the present invention provides an apparatus for adjusting a gain of an analog-to-digital conversion module in a television, the apparatus comprising:
the input module is used for inputting a square wave signal to the analog-to-digital conversion module during the field synchronization period of the analog video signal, wherein the amplitude of the square wave signal is smaller than the maximum amplitude of the analog video signal;
and the adjusting module is used for adjusting the gain of the analog-to-digital conversion module if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range.
Optionally, the adjusted module specifically includes:
the increasing unit is used for increasing the gain of the analog-to-digital conversion module if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is smaller than the lower limit value of the preset range;
and the reducing unit is used for reducing the gain of the analog-to-digital conversion module if the difference value between the average value of the high-level signals and the average value of the low-level signals in the digital video signals is larger than the upper limit value of the preset range.
In a fourth aspect, the present invention provides an apparatus for adjusting an offset of an analog-to-digital conversion module in a television, the apparatus comprising:
the input module is used for inputting the analog video signal to the analog-to-digital conversion module during the field synchronization period of the analog video signal;
and the adjusting module is used for adjusting the offset of the analog-to-digital conversion module if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range.
Optionally, the adjusting module specifically includes:
the increasing unit is used for increasing the offset of the analog-to-digital conversion module if the average value of the digital video signals is smaller than the lower limit value of the preset range;
and the reducing unit is used for reducing the offset of the analog-to-digital conversion module if the average value of the digital video signals is larger than the upper limit value of the preset range.
The technical scheme provided by the invention has the beneficial effects that:
inputting a square wave signal to an analog-to-digital conversion module during the field synchronization period of the analog video signal to obtain a digital video signal output by the analog-to-digital conversion module; and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the gain of the analog-to-digital conversion module. Inputting an analog video signal to the analog-to-digital conversion module during the field synchronization period of the analog video signal to obtain a digital video signal output by the analog-to-digital conversion module; and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the gain of the analog-to-digital conversion module. Therefore, during the field synchronization of the analog video signal, namely in the process of converting the analog video signal by the analog-to-digital conversion module, the gain or the offset of the analog-to-digital conversion module can be adjusted, and the phenomenon that the picture of the video deviates is avoided.
Drawings
Fig. 1-1 is a schematic structural diagram of a video playing device according to an embodiment of the present invention;
fig. 1-2 are schematic structural diagrams of another video playing device provided in an embodiment of the present invention;
fig. 1-3 are schematic structural diagrams of another video playing device provided in an embodiment of the present invention;
fig. 2-1 is a flowchart of a method for adjusting a gain of an analog-to-digital conversion module in a television according to an embodiment of the present invention;
fig. 2-2 is a flowchart of a method for adjusting an offset of an analog-to-digital conversion module in a television according to an embodiment of the present invention;
fig. 3-1 is a flowchart of a method for adjusting a gain of an analog-to-digital conversion module in a television according to an embodiment of the present invention;
FIG. 3-2 is a schematic diagram of a composite sync signal, a field sync signal, and a line sync signal provided by an embodiment of the present invention;
fig. 4 is a flowchart of a method for adjusting an offset of an analog-to-digital conversion module in a television according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an apparatus for adjusting a gain of an analog-to-digital conversion module in a television according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of an apparatus for adjusting an offset of an analog-to-digital conversion module in a television according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Referring to fig. 1-1, an embodiment of the present invention provides a video playback device a, which may be a television or a video player. The video playback device a includes:
the device comprises a video signal source 1, a square wave signal source 2, an analog-to-digital conversion module 3 and an adjusting module 4. The output end of the video signal source 1 is connected with the input end of the analog-to-digital conversion module 3 through a first switch S1, the output end of the square wave signal source 2 is connected with the input end of the analog-to-digital conversion module 3 through a second switch S2, and the output end of the analog-to-digital conversion module 3 is connected with the adjustment module 4.
The video signal source 1 is configured to receive an externally input analog video signal and output the analog video signal to the analog-to-digital conversion module 4. The square wave signal source 2 is used for generating a square wave signal and outputting the square wave signal to the analog-to-digital conversion module 4. The amplitude of the square wave signal is less than the maximum amplitude of the analog video signal. Optionally, the difference between the amplitude of the high level signal and the amplitude of the low level signal of the square wave signal is V1Wherein V is1＝S*V2S is a predetermined coefficient and less than 1, and may be, for example, 0.5 or 0.4, and V2Is the signal amplitude of the analog video signal at full amplitude. Alternatively, the width of the high level signal and the width of the low level signal may both be equal to one line syncThe signal period length of the signal facilitates alignment of the square wave signal with the row sync signal.
When the video playing device a is started, the gain and the offset of the analog-to-digital conversion module 3 are set, then the first switch S1 is controlled to be closed, the second switch S2 is opened, the analog-to-digital conversion module 3 receives the analog video signal output by the video signal source 1, the analog video signal is converted into a digital video signal according to the gain and the offset of the analog-to-digital conversion module, and then the digital video signal is played by the video playing device a.
In the process of playing the video signal by the video playing device a, because the video playing device a generates heat, the gain and the offset of the analog-to-digital conversion module 3 may not be appropriate, the analog-to-digital conversion module 3 converts the analog video signal according to the gain and the offset thereof to obtain the digital video signal, and the phenomenon of color deviation of the playing picture occurs when the video playing device a plays the digital video signal. In order to avoid the color deviation phenomenon of the playing picture, the gain and the offset of the analog-to-digital conversion module 3 are adjusted by the adjusting module 4 in the process of normally playing the video signal by the video playing device a.
The adjusting module 4 may adjust the gain and the offset of the analog-to-digital conversion module 3 by:
controlling the square wave signal source 2 to input the square wave signal to the analog-to-digital conversion module 3; then, the adjusting module 4 obtains the digital video signal output by the analog-to-digital conversion module 3 according to the square wave signal and the gain of the analog-to-digital conversion module 3, and adjusts the gain of the analog-to-digital conversion module 3 if the amplitude of the digital video signal output by the analog-to-digital conversion module 3 is not within the preset range. Or, controlling the video signal source 1 to input an analog video signal to the analog-to-digital conversion module 3; then, the adjusting module 4 obtains the digital video signal output by the analog-to-digital conversion module 3 according to the analog video signal and the gain and offset of the analog-to-digital conversion module 3, and adjusts the offset of the analog-to-digital conversion module 3 if the amplitude of the digital video signal output by the analog-to-digital conversion module 3 is not within the preset range.
Referring to fig. 1-2, the analog-to-digital conversion block 3 includes a converter 31, a register 32, a reference voltage circuit 33, and a clamp circuit 34. The output terminal of the video signal source 1 is connected to the first input terminal of the converter 31 through a first switch S1, and the output terminal of the square wave signal source 2 is connected to the second input terminal of the converter 31 through a second switch S2.
The reference voltage circuit 33 is connected to the register 32, a first output terminal of the reference voltage circuit 33 is connected to an input terminal of the clamp circuit 34, and an output terminal of the clamp circuit 34 is connected to a first input terminal of the converter 31 through the third switch S3; a second output terminal of the reference voltage circuit 33 is connected to a third input terminal of the converter 31; the output of the converter 31 is connected to the adjustment module 4, and the adjustment module 4 is connected to the register 32. The converter 31 may be an ADC.
The register 32 is used to hold the gain and offset of the analog-to-digital conversion module 3. The adjustment of the gain and the offset of the analog-to-digital conversion module 3 is substantially the gain and the offset stored in the adjustment register 32, and the adjustment process includes two processes, respectively: the first process adjusts the gain stored in the register, and the second process adjusts the offset stored in the register.
First, a first process is performed in which the first switch S1 and the third switch S3 are controlled to be opened, the second switch S2 is controlled to be closed, so as to disconnect the analog signal source 1 from the converter 31, and connect the square wave signal source 2 to the converter 31; the square wave signal source 2 inputs a square wave signal to the converter 31, the reference voltage circuit 33 generates a reference voltage signal according to the gain stored in the register, and the reference voltage signal is input to the converter 31; the converter 31 converts the square wave signal according to the reference voltage signal and outputs a digital video signal; the adjusting module 4 receives the digital video signal, and adjusts the gain stored in the register if the amplitude of the digital video signal is not within the preset range.
Then, a second process is performed in which the first switch S1 and the third switch S3 are controlled to be closed, the second switch S2 is opened to disconnect the connection between the square wave signal source 2 and the converter 31, and the video signal source 2 and the converter 31 are connected; the video signal source 1 inputs an analog video signal to the converter 31, the reference voltage circuit 33 generates a reference voltage signal and an offset voltage signal according to the gain and offset amount stored in the register, inputs the reference voltage signal to the converter 31, and inputs the offset voltage signal to the clamp circuit 34; the clamp circuit 34 generates a clamp voltage signal according to the offset voltage signal, and inputs the clamp voltage signal to the converter 31; the converter 31 converts the analog video signal and the clamp voltage signal into a digital video signal according to the reference voltage signal; the adjusting module 4 receives the digital video signal, and adjusts the offset amount stored in the register if the amplitude of the digital video signal is not within the preset range.
Optionally, referring to fig. 1 to 3, the video playing device a includes three video signal sources 1 and three analog-to-digital conversion modules 3. The three video signal sources are respectively a first video signal source 11, a second video signal source 12 and a third video signal source 13, and the three analog-to-digital conversion modules 3 are respectively a first analog-to-digital conversion module 3a, a second analog-to-digital conversion module 3b and a third analog-to-digital conversion module 3 c; the first video signal source 11 is connected with the first analog-to-digital conversion module 3a, the second video signal source 12 is connected with the second analog-to-digital conversion module 3b, and the third video signal source 13 is connected with the third analog-to-digital conversion module 3 c. The first analog-to-digital conversion module 3a, the second analog-to-digital conversion module 3b and the third analog-to-digital conversion module 3c are respectively connected with the square wave signal source 2 and the adjusting module 4.
The three video signal sources 1 are respectively used for outputting analog video signals of different channels. For example, the first video source 11 is configured to output a first analog video signal of an R or Pr channel, the second video source 12 is configured to output a second analog video signal of a G or Y channel, and the third video source 13 is configured to output a third analog video signal of a B or Pb channel.
The first analog-to-digital conversion module 3a is configured to convert a first analog video signal output by the first video signal source 11 into a digital video signal; the second analog-to-digital conversion module 3b is configured to convert a second analog video signal output by the second video signal source 12 into a digital video signal; and a third analog-to-digital conversion module 3c, configured to convert a third analog video signal output by the third video signal source 13 into a digital video signal.
The adjusting module 4 may obtain the digital video signal output by the first analog-to-digital converting module 3a, the digital video signal output by the second analog-to-digital converting module 3b, and the digital video signal output by the third analog-to-digital converting module 3c, and may adjust the gain and offset of the first analog-to-digital converting module 3a, the gain and offset of the second analog-to-digital converting module 3b, and the gain and offset of the third analog-to-digital converting module 3 c.
The second analog video signal output by the second video signal source 12 includes a composite synchronization signal including a field synchronization signal and a line synchronization signal, and the relationship of these three signals is shown in fig. 3-2.
Referring to fig. 1-3, the video playback device a further includes a slicing circuit 5, where the slicing circuit 5 is connected to the second video signal source 12, and is configured to separate a field sync signal and a line sync signal from the second analog video signal of the second video signal source 12, and further configured to output the field sync signal to the adjusting module 4. The adjusting module 4 starts to adjust the gain and the offset of the analog-to-digital converting module 3 when the field sync signal is at a high level.
The field synchronizing signal is used for the video playing device A to switch the currently played video picture, the video playing device A switches the currently played video picture when the field synchronizing signal is a high level signal, and the switched video picture is displayed when the field synchronizing signal is a low level signal. Therefore, when the field sync signal is a high level signal, the video playing device a does not display a video picture, and the adjusting module 4 starts to adjust the gain and the offset of the analog-to-digital conversion module 3 when the field sync signal is a high level signal, so that the display picture of the video playing device a is not affected.
Referring to fig. 1-3, the square wave signal source 2 includes a bandgap reference source and a square wave standard signal generating circuit, and the bandgap reference source generates a reference signal and inputs the reference signal to the square wave standard signal generating circuit. The square wave standard signal generating circuit receives the reference signal, generates a square wave signal according to the reference signal and outputs the square wave signal.
Among them, it should be noted that: the square wave signal source 2, the analog-to-digital conversion module 3, the adjustment module 4, the first switch S1, the second switch S2, and the third switch S3 may be integrated into one chip or may be integrated into different chips.
In the process of playing signals by the video playing device a, the gain and the offset of the analog-to-digital conversion module 3 are adjusted in real time by the adjusting module 4, so that the conversion parameters of the analog-to-digital conversion module 3 are appropriate, and the phenomenon that the color of the played picture deviates from the image is avoided.
Referring to fig. 2-1, the present invention provides a method for adjusting a gain of an analog-to-digital conversion module in a television, the method comprising:
step 201: during the field synchronization of the analog video signal, a square wave signal having an amplitude smaller than the maximum amplitude of the analog video signal is input to the analog-to-digital conversion module.
The field sync period of the analog video signal refers to a period in which the field sync signal in the analog video signal is a high-level signal.
Step 202: and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the gain of the analog-to-digital conversion module.
Optionally, step 202 may be:
2021: if the difference value between the average value of the high level signal and the average value of the low level signal in the digital video signal is smaller than the lower limit value of a preset range, increasing the gain of an analog-to-digital conversion module;
2022: and if the difference value between the average value of the high-level signals and the average value of the low-level signals in the digital video signal is larger than the upper limit value of the preset range, reducing the gain of the analog-to-digital conversion module.
In the embodiment of the invention, a square wave signal is input to an analog-to-digital conversion module, and a digital video signal output by the analog-to-digital conversion module according to the square wave signal is obtained; and if the amplitude of the digital video signal is not within the preset range, adjusting the gain of the analog-to-digital conversion module. Therefore, in the process of converting the analog video signal by the analog-to-digital conversion module, the gain of the analog-to-digital conversion module can be adjusted, and the phenomenon of color deviation of a video picture is avoided.
Referring to fig. 2-2, the present invention provides a method for adjusting an offset of an analog-to-digital conversion module in a television, the method comprising:
step 210: during field synchronization of the analog video signal, the analog video signal is input to the analog-to-digital conversion module.
The field sync period of the analog video signal refers to a period in which the field sync signal in the analog video signal is a high-level signal.
Step 211: and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the offset of the analog-to-digital conversion module.
Optionally, step 211 may be:
2011: if the difference value between the average value of the high level signal and the average value of the low level signal in the digital video signal is smaller than the lower limit value of a preset range, increasing the offset of an analog-to-digital conversion module;
2012: if the difference value between the average value of the high level signal and the average value of the low level signal in the digital video signal is larger than the upper limit value of the preset range, the offset of the analog-to-digital conversion module is reduced.
In the embodiment of the invention, an analog video signal is input to an analog-to-digital conversion module, and a digital video signal output by the analog-to-digital conversion module according to the analog video signal is obtained; and if the amplitude of the digital video signal is not in the preset range, adjusting the offset of the analog-to-digital conversion module. Therefore, in the process of converting the analog video signal by the analog-to-digital conversion module, the offset of the analog-to-digital conversion module can be adjusted, and the phenomenon of color deviation of a video picture is avoided.
The embodiment of the invention provides a method for adjusting conversion parameters, which is applied to video playing equipment shown in figures 1-1, 1-2 or 1-3, wherein the conversion parameters of an analog-to-digital conversion module comprise gain and offset of the analog-to-digital conversion module.
Referring to fig. 3-1, an embodiment of the present invention provides a method for adjusting a gain of an analog-to-digital conversion module in a television, including:
step 301: the field sync signal is separated from the analog video signal output from the video signal source, and step 302 is performed when the field sync signal is a high level signal.
The video signal source is a second video signal source 12 corresponding to a G or Y channel, and the analog video signal output by the second video signal source 12 includes a field sync signal. Step 302 may be performed when the field sync signal changes from a low level signal to a high level signal, and step 302 may be stopped from being continuously performed when the field sync signal changes from a high level signal to a low level signal.
The field synchronizing signal is used for switching the display picture of the video playing device, the video playing device switches the display picture when the field synchronizing signal is in a high level signal, and the switched picture is displayed when the field synchronizing signal is in a low level signal. Therefore, the video playing device does not display the picture when the field synchronizing signal is in the high level signal, and the process of executing the subsequent gain adjustment does not influence the picture displayed by the video playing device.
Step 302: and the square wave signal output by the square wave signal source and the analog video signal output by the video signal source are stopped being input to the analog-to-digital conversion module.
Specifically, the first switch S1 and the third switch S3 are controlled to be opened to stop inputting the analog video signal output by the video signal source to the analog-to-digital conversion module, and the second switch S2 is controlled to be closed to input the square wave signal output by the square wave signal source to the converter 31 included in the analog-to-digital conversion module through the second switch S2.
In this step, after the square wave signal output by the square wave signal source is input to the converter of the analog-to-digital conversion module, the reference voltage circuit in the analog-to-digital conversion module reads the saved gain from the register, generates a reference voltage signal according to the gain and inputs the reference voltage signal to the converter; the converter receives the square wave signal and a reference voltage signal, converts the square wave signal into a digital video signal according to the reference voltage signal and outputs the digital video signal.
High level signal magnitude and low level signal magnitude of square wave signalWith a difference of V1In which V is1＝S*V2S is a predetermined coefficient, V2Is the signal amplitude of the analog video signal at full amplitude. Usually, S is 0.5, and in addition to this, S may be 0.3 or 0.4. For example, the high level signal magnitude of the square wave signal may be 0.75V2The low level signal may be 0.25V2(ii) a Alternatively, the high level signal size of the square wave signal is to be 0.8V2The low level signal can be 0.4V2And the like.
Step 303: and acquiring the digital video signal output by the analog-to-digital conversion module.
In this step, a digital video signal of one signal period may be acquired or a digital video signal of a plurality of signal periods may be acquired.
Referring to fig. 3-2, in one signal period, a part of the digital video signal exists as a high level signal, and the rest part of the digital video signal exists as a low level signal. The amplitude of the high level signal may be fixed or may fluctuate during any signal period, and the amplitude of the low level signal may be fixed or may fluctuate.
Step 304: an average value of high level signals and an average value of low level signals included in the digital video signal are calculated, and a first difference between the two average values is calculated.
If the digital video signal in only one signal period is acquired in step 303, an average value of the amplitude levels of the high-level signals included in the digital video signal is calculated, and an average value of the amplitude levels of the low-level signals included in the digital video signal is calculated, and then a first difference between the two average values is calculated.
If the digital video signals in the plurality of signal periods are acquired in step 303, an average value is calculated according to the magnitude of the high level signal included in the digital video signal in each signal period, another average value is calculated according to the magnitude of the low level signal included in the digital video signal in each signal period, and then a first difference value between the two average values is calculated.
Step 305: and judging the relation between the first difference value and the preset range.
The preset range is a variation range of an amplitude difference value between an amplitude of a high level signal and an amplitude of a low level signal of the standard digital video signal, so the preset range of the step is the variation range of the preset amplitude difference value.
The preset range can be set in advance according to a preset coefficient S and the number of codes included in the standard full-width digital video signal output by the analog-to-digital conversion module. Wherein a product value between a predetermined coefficient S and the code number is calculated, and if the gain and offset of the analog-to-digital conversion module are appropriate, the first difference value fluctuates around the product value. A preset range may be set, a lower limit value of the preset range being smaller than the product value and a difference value with the product value not exceeding a preset threshold, and an upper limit value of the preset range being larger than the product value and a difference value with the product value not exceeding a preset threshold.
For example, assuming that the converter in the analog-to-digital conversion module is a 10-bit converter, and the preset coefficient S is 0.5, the standard full-width digital video signal output by the analog-to-digital conversion module includes 1024 codes, that is, the number of codes is 1024, and the value of the product of the preset coefficient S and the number of codes is calculated to be 512. For such an analog-to-digital conversion module, a preset range is set, the difference between the lower limit value of the preset range and the product value 512 does not exceed the preset threshold value 1, and the difference between the upper limit value of the preset range and the product value 512 does not exceed the preset threshold value 1, that is, the preset range may be set to be greater than or equal to 511 and less than or equal to 513.
Step 306: if the first difference is smaller than the lower limit of the preset range, the gain stored in the register is increased, and the step 301 is executed.
Alternatively, a value may be preset, and the gain held in the register may be increased when the gain is increased.
Step 307: if the first difference is greater than the upper limit of the preset range, the gain stored in the register is decreased, and the process returns to step 301.
Alternatively, the gain held in the register may be decreased by this value when the gain is decreased.
If the first difference value is in the preset range, the gain stored in the current register is proper, and the digital video signal obtained by the analog-digital conversion module through conversion according to the gain in the register does not have the phenomenon that the color of the picture deviates from the image, so that the adjustment of the gain stored in the register can be finished.
Referring to fig. 4, an embodiment of the present invention provides a method for adjusting an offset of an analog-to-digital conversion module in a television, where the method is performed after the procedure of adjusting a gain shown in fig. 3-1 is performed, and the method includes:
step 401: the field sync signal is separated from the analog video signal output from the video signal source, and step 402 is performed when the field sync signal is a high level signal.
When the field synchronizing signal is in a high level signal, the video playing device does not display the picture, and the process of executing the subsequent adjustment offset does not influence the picture displayed by the video playing device.
Step 402: and the analog video signal output by the video signal source is input to the analog-to-digital conversion module, and the square wave signal output by the square wave signal source is stopped being input to the analog-to-digital conversion module.
Specifically, the first switch S1 and the third switch S3 are controlled to be closed, so that the analog video signal output by the video signal source is input into the converter 31 included in the analog-to-digital conversion module through the first switch S1; the second switch S2 is controlled to be turned off to stop inputting the square wave signal output by the square wave signal source to the analog-to-digital conversion module.
In this step, after the analog video signal output by the video signal source is input to the converter of the analog-to-digital conversion module, the reference voltage circuit in the analog-to-digital conversion module reads the saved gain and offset from the register, where the gain is the gain adjusted by the process shown in fig. 3-1, a reference voltage signal and an offset voltage signal are generated according to the gain and the offset, the reference voltage signal is input to the converter, and the offset voltage signal is input to the clamp circuit; the clamp circuit receives the offset voltage signal and generates a clamp voltage signal, which is input to the converter. The converter receives the analog video signal, the clamping voltage signal and the reference voltage signal, converts the analog video signal and the clamping voltage signal into a digital video signal according to the reference voltage signal and outputs the digital video signal.
Step 403: and acquiring the digital video signal output by the analog-to-digital conversion module.
In this step, a digital video signal of one signal period may be acquired or a second digital video signal of a plurality of signal periods may be acquired.
In one signal period, part of the digital video signals are high-level signals, and the rest part of the digital video signals are low-level signals. The amplitude of the high level signal may be fixed or may fluctuate during any signal period, and the amplitude of the low level signal may be fixed or may fluctuate.
Step 404: an average value of the amplitude of the digital video signal is calculated.
If the digital video signal is acquired in only one signal period in step 403, the average value of the amplitude of the digital video signal is calculated. If the digital video signal is acquired over a plurality of signal periods in step 403, an average value is calculated from the amplitude of the digital video signal over each signal period.
Step 405: and judging the relation between the average value of the digital video signal and a preset range.
The preset range may be set to be greater than or equal to 9 and less than or equal to 11. The preset range in this step is different from the preset range in the embodiment shown in fig. 3-1. The preset range in this step is a preset range of amplitude average variation.
Step 406: if the average value of the digital video signal is smaller than the lower limit value of the preset range, the offset saved in the register is increased, and the step 401 is executed.
Alternatively, a value may be set in advance, and the value may be added to the offset stored in the register when the offset is added.
Step 407: if the average value of the digital video signal is greater than the upper limit value of the preset range, the offset value stored in the register is reduced, and the step 401 is executed.
Alternatively, the offset value stored in the register may be reduced by this value when the offset value is reduced.
If the average value of the digital video signal is in the preset range, the offset stored in the current register is proper, and the digital video signal obtained by the analog-to-digital conversion module through conversion according to the gain and the offset in the register does not have the phenomenon that the color of the picture deviates from the current picture, so that the adjustment of the offset stored in the register can be finished continuously.
In the embodiment of the invention, a square wave signal is input to the analog-to-digital conversion module, and a digital video signal output by the analog-to-digital conversion module according to the square wave signal and the gain of the analog-to-digital conversion module is obtained; adjusting the gain of the analog-to-digital conversion module according to the digital video signal and a preset range corresponding to the standard digital video signal; after the gain is adjusted, the analog video signal is input to the analog-to-digital conversion module, and the digital video signal output by the analog-to-digital conversion module according to the analog video signal and the gain and offset of the analog-to-digital conversion module is obtained; and adjusting the offset of the analog-to-digital conversion module according to the digital video signal and another preset range corresponding to the standard digital video signal. Therefore, in the process of converting the analog video signal by the analog-to-digital conversion module, the gain and the offset of the analog-to-digital conversion module can be adjusted, and the phenomenon that the color of a video picture deviates is avoided. In addition, the gain and the offset are adjusted in real time when the field synchronizing signal is in a high level signal, the video playing equipment switches the played video frame when the field synchronizing signal is in the high level signal, and the video picture cannot be played on the screen in the period of time, so that the adjustment of the gain and the offset cannot influence the normal playing of the video picture.
Referring to fig. 5, an embodiment of the present invention provides an apparatus 500 for adjusting a gain of an analog-to-digital conversion module in a television, where the apparatus 500 includes:
an input module 501, configured to input a square wave signal to an analog-to-digital conversion module during a field synchronization period of an analog video signal, where an amplitude of the square wave signal is smaller than a maximum amplitude of the analog video signal;
an adjusting module 502, configured to adjust a gain of the analog-to-digital conversion module if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range.
Optionally, the adjusted module 502 specifically includes:
the increasing unit is used for increasing the gain of the analog-to-digital conversion module if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is smaller than the lower limit value of the preset range;
and the reducing unit is used for reducing the gain of the analog-to-digital conversion module if the difference value between the average value of the high-level signals and the average value of the low-level signals in the digital video signals is larger than the upper limit value of the preset range.
If the amplitude of the digital video signal output by the analog-to-digital conversion module is within a preset range, the implementation may adjust the offset of the analog-to-digital conversion module through the following embodiment shown in fig. 6.
In the embodiment of the invention, a square wave signal is input to the analog-to-digital conversion module during the field synchronization period of the analog video signal, and a digital video signal output by the analog-to-digital conversion module according to the square wave signal is obtained; and if the amplitude of the digital video signal is not in the preset range, adjusting the gain of the analog-to-digital conversion module. Therefore, in the process of converting the analog video signal by the analog-to-digital conversion module, the gain of the analog-to-digital conversion module can be adjusted, and the phenomenon of color deviation of a video picture is avoided.
Referring to fig. 6, an embodiment of the present invention provides an apparatus 600 for adjusting an offset of an analog-to-digital conversion module in a television, where the apparatus 600 includes:
an input module 601, configured to input an analog video signal to the analog-to-digital conversion module during a field synchronization period of the analog video signal;
an adjusting module 602, configured to adjust an offset of the analog-to-digital conversion module if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range.
Optionally, the adjusting module 602 specifically includes:
the increasing unit is used for increasing the offset of the analog-to-digital conversion module if the average value of the digital video signals is smaller than the lower limit value of the preset range;
and the reducing unit is used for reducing the offset of the analog-to-digital conversion module if the average value of the digital video signals is larger than the upper limit value of the preset range.
In the embodiment of the invention, the analog video signal is input to the analog-to-digital conversion module during the field synchronization period of the analog video signal, and the digital video signal output by the analog-to-digital conversion module according to the analog video signal is obtained; if the amplitude of the digital video signal is not within the preset range, the offset of the analog-to-digital conversion module is adjusted. Therefore, in the process of converting the analog video signal by the analog-to-digital conversion module, the offset of the analog-to-digital conversion module can be adjusted, and the phenomenon of color deviation of a video picture is avoided.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disk, or the like.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A method for adjusting the gain of an analog-to-digital conversion module in a television is characterized in that the television comprises a chip dividing circuit, a video signal source, a square wave signal source, an analog-to-digital conversion module and an adjusting module, wherein the output end of the video signal source is connected with the input end of the analog-to-digital conversion module through a first switch, the output end of the square wave signal source is connected with the input end of the analog-to-digital conversion module through a second switch, the output end of the analog-to-digital conversion module is connected with the adjusting module, the video signal source comprises a first video signal source, a second video signal source and a third video signal source, the analog-to-digital conversion module comprises a first analog-to-digital conversion module, a second analog-to-digital conversion module and a third analog-to-digital conversion module, the first video signal source is connected with the first analog-to-, the third video signal source is connected with the third analog-to-digital conversion module, the first analog-to-digital conversion module, the second analog-to-digital conversion module and the third analog-to-digital conversion module are respectively connected with the square wave signal source and the adjustment module, the slicing circuit is connected with the second video signal source, and the first video signal source, the second video signal source and the third video signal source are respectively used for outputting analog video signals of different channels, wherein the method comprises the following steps:
during the field synchronization period of the analog video signal, controlling the first switch to be switched off and the second switch to be switched on, and inputting a square wave signal to the analog-to-digital conversion module through the square wave signal source, wherein the amplitude of the square wave signal is smaller than the maximum amplitude of the analog video signal, and the field synchronization period is a time period in which a field synchronization signal separated from a second analog video signal in the second video signal source in the split power is a high-level signal;
and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the gain of the analog-to-digital conversion module through the adjusting module.
2. The method of claim 1, wherein if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range, adjusting the gain of the analog-to-digital conversion module comprises:
if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is smaller than the lower limit value of the preset range, increasing the gain of the analog-to-digital conversion module;
and if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is larger than the upper limit value of the preset range, reducing the gain of the analog-to-digital conversion module.
3. A method for adjusting an offset of an analog-to-digital conversion module in a television, the method comprising:
inputting an analog video signal to an analog-to-digital conversion module during field synchronization of the analog video signal, wherein the analog-to-digital conversion module outputs a digital video signal according to the analog video signal and a gain and an offset of the analog-to-digital conversion module, the gain being obtained by the method of claim 1 or 2;
and if the amplitude of the digital video signal output by the analog-to-digital conversion module is not in a preset range, adjusting the offset of the analog-to-digital conversion module.
4. The method of claim 3, wherein if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range, adjusting the offset of the analog-to-digital conversion module comprises:
if the average value of the digital video signals is smaller than the lower limit value of the preset range, increasing the offset of the analog-to-digital conversion module;
and if the average value of the digital video signals is larger than the upper limit value of the preset range, reducing the offset of the analog-to-digital conversion module.
5. A device for adjusting the gain of an analog-to-digital conversion module in a television is characterized in that the television comprises a chip dividing circuit, a video signal source, a square wave signal source, an analog-to-digital conversion module and an adjusting module, wherein the output end of the video signal source is connected with the input end of the analog-to-digital conversion module through a first switch, the output end of the square wave signal source is connected with the input end of the analog-to-digital conversion module through a second switch, the output end of the analog-to-digital conversion module is connected with the adjusting module, the video signal source comprises a first video signal source, a second video signal source and a third video signal source, the analog-to-digital conversion module comprises a first analog-to-digital conversion module, a second analog-to-digital conversion module and a third analog-to-digital conversion module, the first video signal source is connected with the first analog-to-, the third video signal source is connected to the third analog-to-digital conversion module, the first analog-to-digital conversion module, the second analog-to-digital conversion module and the third analog-to-digital conversion module are respectively connected to the square wave signal source and the adjustment module, the slicing circuit is connected to the second video signal source, the first video signal source, the second video signal source and the third video signal source are respectively used for outputting analog video signals of different channels, and the apparatus includes:
the input module is used for controlling the first switch to be switched off and the second switch to be switched on during the field synchronization period of the analog video signal, and inputting a square wave signal to the analog-to-digital conversion module through the square wave signal source, wherein the amplitude of the square wave signal is smaller than the maximum amplitude of the analog video signal, and the field synchronization period is a time period when the field synchronization signal separated from the second analog video signal in the second video signal source in the slicing circuit is a high-level signal;
and the adjusting module is used for adjusting the gain of the analog-to-digital conversion module if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range.
6. The apparatus of claim 5, wherein the adjusting module specifically comprises:
the increasing unit is used for increasing the gain of the analog-to-digital conversion module if the difference value between the average value of the high level signals and the average value of the low level signals in the digital video signals is smaller than the lower limit value of the preset range;
and the reducing unit is used for reducing the gain of the analog-to-digital conversion module if the difference value between the average value of the high-level signals and the average value of the low-level signals in the digital video signals is larger than the upper limit value of the preset range.
7. An apparatus for adjusting an offset of an analog-to-digital conversion module in a television, the apparatus comprising:
an input module for inputting an analog video signal to an analog-to-digital conversion module during a field synchronization of the analog video signal, wherein the analog-to-digital conversion module outputs a digital video signal according to the analog video signal and a gain and an offset of the analog-to-digital conversion module, the gain being obtained by the method of claim 1 or 2;
and the adjusting module is used for adjusting the offset of the analog-to-digital conversion module if the amplitude of the digital video signal output by the analog-to-digital conversion module is not within a preset range.
8. The apparatus of claim 7, wherein the adjustment module specifically comprises:
the increasing unit is used for increasing the offset of the analog-to-digital conversion module if the average value of the digital video signals is smaller than the lower limit value of the preset range;
and the reducing unit is used for reducing the offset of the analog-to-digital conversion module if the average value of the digital video signals is larger than the upper limit value of the preset range.
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