CN210431681U - Device for carrying out frequency conversion measurement on video color subcarrier - Google Patents
Device for carrying out frequency conversion measurement on video color subcarrier Download PDFInfo
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- CN210431681U CN210431681U CN201921829287.3U CN201921829287U CN210431681U CN 210431681 U CN210431681 U CN 210431681U CN 201921829287 U CN201921829287 U CN 201921829287U CN 210431681 U CN210431681 U CN 210431681U
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Abstract
The utility model discloses a device for carrying out frequency conversion measurement on video color subcarrier, which comprises a color subcarrier filter, an amplifier and a singlechip system, wherein the output end of the color subcarrier filter is connected with the input end of the amplifier, and the output end of the amplifier is connected with a counting unit of the singlechip system; the color subcarrier filter is used for filtering a video signal of a color subcarrier frequency to be detected, the amplifier is used for amplifying a carrier obtained by filtering, the counting unit is used for counting the signal obtained by amplification, and the singlechip system receives counting time and a counting result fed back by the counting unit. The utility model discloses filter, enlarge and count again after the operation to the look subcarrier, obtain count frequency conduct the switching frequency of look subcarrier, for subsequent frequency detection device provides the judgement foundation, does not need numerous and diverse calculation and very low to operating personnel's requirement, reduced the possibility of error.
Description
Technical Field
The utility model relates to a look subcarrier frequency measurement field, in particular to are used for carrying out frequency conversion measuring device to video look subcarrier.
Background
The device with composite video output usually has overlarge color subcarrier deviation in the production and manufacturing process, the video receiving device in the market has loose error, the deviation redundancy is very small, the image black and white phenomenon usually occurs when the deviation exceeds 100ppm, the display with high requirement is more required to be less than 10ppm, and for the requirement of color subcarrier frequency, the current national standard has no clear requirement, but the manufacturer usually faces practical problems in reality.
The measurement of the color subcarrier frequency has been conventionally measured using an expensive video analyzer, and no economical and practical instrument for measuring the color subcarrier frequency has been developed in the prior art.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem of the prior art, the utility model provides a device for carrying out frequency conversion measurement to video look subcarrier avoids numerous and diverse calculation, reduces the requirement to operating personnel to reduce frequency measurement error rate, technical scheme is as follows:
the utility model provides a device for carrying out frequency conversion measurement to video color subcarrier, including color subcarrier wave filter, amplifier and single chip microcomputer system, the output of color subcarrier wave filter is connected with the input of amplifier, the output of amplifier is connected with the counting unit of single chip microcomputer system;
the color subcarrier filter is used for filtering a video signal of a color subcarrier frequency to be detected, the amplifier is used for amplifying a carrier obtained by filtering, the counting unit is used for counting the signal obtained by amplification, and the singlechip system receives counting time and a counting result fed back by the counting unit.
Preferably, the color subcarrier filter is a band-pass filter with a bandwidth of-10 KHz to 10 KHz.
Preferably, the color subcarrier filter is a band-pass filter with a bandwidth of-6 KHz to 6 KHz.
Preferably, the amplifier has an operating gain in the range of 20-50 dB.
Preferably, the amplifier has an operating gain in the range of 20-30 dB.
Preferably, the reference frequency error of the counting unit of the single chip microcomputer system is less than 1 ppm.
Preferably, the device for performing frequency conversion measurement on the video color subcarrier further comprises a detection result display connected to an output end of the single chip microcomputer system, and the detection result display is used for displaying an output result of the single chip microcomputer system.
The utility model provides a beneficial effect that technical scheme brought as follows:
a. complex calculation is not needed, the requirement on operators is low, and the possibility of frequency conversion measurement errors is reduced;
b. and counting the signals after filtering and amplifying, and converting counting time and counting results to obtain frequency information.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a block diagram of an apparatus for performing frequency conversion measurement on a video color subcarrier according to an embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.
In an embodiment of the present invention, a device for performing frequency conversion measurement on video color subcarrier is provided, as shown in fig. 1, the device includes a color subcarrier filter, an amplifier and a single chip microcomputer system, an output end of the color subcarrier filter is connected to an input end of the amplifier, an output end of the amplifier is connected to a counting unit of the single chip microcomputer system, and a reference frequency error of the counting unit of the single chip microcomputer system is less than 1 ppm;
the color subcarrier filter is used for filtering a video signal of a color subcarrier frequency to be detected, the amplifier is used for amplifying a carrier obtained by filtering, the counting unit is used for counting the signal obtained by amplification, and the singlechip system receives counting time and a counting result fed back by the counting unit.
In a preferred embodiment of the present invention, the color sub-carrier filter is a band-pass filter with a bandwidth of-10 KHz to 10KHz, preferably-6 KHz to 6 KHz; the operating gain range of the amplifier is 20-50dB, preferably 20-30 dB.
In an embodiment of the present invention, the counting time can be selected to be 0.1s, and then the counting is performed in 0.1s, and for the case where the accuracy requirement is higher, 1s or longer can be selected.
The single chip microcomputer system receives the counting time and the counting result fed back by the counting unit, and based on the calculation function of the single chip microcomputer and a known frequency calculation formula:
the singlechip can output the counting frequency as the conversion frequency of the video color subcarrier, wherein fCountingFor the counting frequency, c _ num is the counting result, and c _ time is the counting time.
In a preferred embodiment of the present invention, the device for measuring the frequency conversion of the video color subcarrier further comprises a detection result display connected to the output end of the single chip microcomputer system, and the detection result display is used for displaying the output result of the single chip microcomputer system.
The embodiment of the utility model provides an in the follow-up video look subcarrier frequency detection device that can input of the switching frequency of the video look subcarrier that measures, by video look subcarrier frequency detection device calculates the proportional error through following formula:
δppm＝(fcounting/fref-1)×106Wherein, deltappmAs a proportional error, fCountingTo count the frequency, frefAs a reference frequency, the reference frequency fref＝4.43361875MHz。
After the calculation result is obtained, the video color subcarrier frequency detection device judges whether the absolute value of the proportional error is smaller than or equal to the preset allowable proportional error threshold value, if so, the color subcarrier frequency detection result of the video signal is judged to be qualified, and if not, the color subcarrier frequency detection result of the video signal is judged to be unqualified.
The utility model discloses filter, enlarge and count again after the operation to the look subcarrier, obtain count frequency conduct the switching frequency of look subcarrier, for subsequent frequency detection device provides the judgement foundation, does not need numerous and diverse calculation and very low to operating personnel's requirement, reduced the possibility of error.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims (7)
1. A device for carrying out frequency conversion measurement on video color subcarrier is characterized by comprising a color subcarrier filter, an amplifier and a single chip microcomputer system, wherein the output end of the color subcarrier filter is connected with the input end of the amplifier, and the output end of the amplifier is connected with a counting unit of the single chip microcomputer system;
the color subcarrier filter is used for filtering a video signal of a color subcarrier frequency to be detected, the amplifier is used for amplifying a carrier obtained by filtering, the counting unit is used for counting the signal obtained by amplification, and the singlechip system receives counting time and a counting result fed back by the counting unit.
2. The apparatus of claim 1, wherein the color subcarrier filter is a band pass filter having a bandwidth of-10 KHz to 10 KHz.
3. The apparatus of claim 2, wherein the color subcarrier filter is a band pass filter having a bandwidth of-6 KHz to 6 KHz.
4. The apparatus of claim 1, wherein the amplifier has an operating gain in the range of 20-50 dB.
5. The apparatus of claim 4, wherein the amplifier has an operating gain in the range of 20-30 dB.
6. The apparatus according to claim 1, wherein the reference frequency error of the counting unit of the one-chip microcomputer system is less than 1 ppm.
7. The apparatus according to claim 1, further comprising a detected result display connected to an output of the single chip microcomputer system, wherein the detected result display is used for displaying an output result of the single chip microcomputer system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921829287.3U CN210431681U (en) | 2019-10-29 | 2019-10-29 | Device for carrying out frequency conversion measurement on video color subcarrier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921829287.3U CN210431681U (en) | 2019-10-29 | 2019-10-29 | Device for carrying out frequency conversion measurement on video color subcarrier |
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| Publication Number | Publication Date |
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| CN210431681U true CN210431681U (en) | 2020-04-28 |
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| CN201921829287.3U Active CN210431681U (en) | 2019-10-29 | 2019-10-29 | Device for carrying out frequency conversion measurement on video color subcarrier |
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| CN (1) | CN210431681U (en) |
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2019
- 2019-10-29 CN CN201921829287.3U patent/CN210431681U/en active Active
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