CN101764985B - Composite video signal attenuating device - Google Patents
Composite video signal attenuating device Download PDFInfo
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- CN101764985B CN101764985B CN2009101932784A CN200910193278A CN101764985B CN 101764985 B CN101764985 B CN 101764985B CN 2009101932784 A CN2009101932784 A CN 2009101932784A CN 200910193278 A CN200910193278 A CN 200910193278A CN 101764985 B CN101764985 B CN 101764985B
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- composite video
- video signal
- attenuation
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Abstract
The invention discloses a composite video signal attenuating device, which comprises an amplitude attenuating module, a high-efficiency attenuating module, a low-efficiency attenuating module, a proportion odd attenuating module and a selection module, wherein the amplitude attenuating module is used for simultaneously attenuating luminance signals and chroma signals, the high-efficiency attenuating module is used for attenuating chroma signals, the low-efficiency attenuating module is used for attenuating field signals, the proportion odd attenuating module is used for the proportion odd attenuation of synchronizing signals and bright color signals, and the selection module is used for selecting one ore several attenuating module(s) for attenuating composite video signals. The composite video signal attenuating device can flexibly combine the attenuating modes.
Description
Technical field
The present invention relates to a kind of composite video signal attenuating device.
Background technology
In the prior art, be 02106083.5 like the patent No., name is called variable attenuator, and it provides a kind of variable attenuator, can set the high attenuation amount, reduces manufacturing cost and realize whole equipment miniaturization.Concrete, this technology is connected inductance element 3 with the drain electrode of FET2, simultaneously that capacity cell 4 is parallelly connected again with the series circuit of FET2 and inductance element 3, constitutes mode of resonance spst switch 1 like this.In addition, the constant pressure source 7 of service voltage VS is connected with the source electrode of FET2, simultaneously variable voltage generator 9 is connected with the grid of FET2, FET2 is switched near state conducting state and the pinch off.And, utilize the grid of 9 couples of FET2 of variable voltage generator to add near the voltage VA the pinch-off voltage, through making spst switch 1 conducting like this, the attenuation between simultaneously can variable setting terminal 5 and 6.
Though this patent can realize attenuation, function singleness, the test occasion that can not meet the demands the various parameters of signal are decayed.
Summary of the invention
To the shortcoming of prior art, the purpose of this invention is to provide a kind of composite video signal attenuating device that can select evanescent mode flexibly.
For realizing above-mentioned purpose, technical scheme of the present invention is: a kind of composite video signal fading simulator, and it comprises with lower module: amplitude attenuation module, decay when being used for luminance and chrominance information; The high frequency attenuation module is used for the decay of carrier chrominance signal; The low cut module is used for the decay of field signal envelope; Ratio very becomes attenuation module, and the ratio that is used for synchronizing signal and bright signal very becomes decay; And select module, be used to select one or more attenuation module that composite video signal is decayed.
This selection module comprises each selector switch that is connected with each attenuation module respectively, and whether each selector switch selects corresponding attenuation module composite video signal to be decayed.
This amplitude attenuation module is made up of bleeder circuit and the 5th selector switch; Bleeder circuit is realized the amplitude attenuation to composite video signal; The 5th selector switch is through selecting various resistance values to change the ratio of dividing potential drop; Thereby the change rate of signal attenuation, and this amplitude attenuation module selects whether to carry out amplitude attenuation through first selector switch.
This high frequency attenuation module is made up of RC circuit and the 6th selector switch; The RC circuit is realized the high frequency attenuation to composite video signal; The 6th selector switch is through selecting various capacitances to change the RC circuit; Thereby change signal high frequency attenuation rate, and this high frequency attenuation module selects whether to carry out high frequency attenuation through second selector switch.
This low cut module is made up of the 2nd RC circuit and the 7th selector switch; The 2nd RC circuit is realized the low cut to composite video signal; The 7th selector switch is through selecting various capacitances to change the RC circuit; Thereby change signal low cut rate, and this low cut module selects whether to carry out low cut through the 3rd selector switch.
This ratio very becomes attenuation module and comprises first video processor, second video processor, buffer, the 8th selector switch and the 9th selector switch; This first video processor is connected with second video processor; And realize the ratio of composite video signal is very become decay; Buffer is realized the output buffers to composite video signal; The 8th selector switch is the bright signal attenuator switch, and the 9th selector switch is used for the strange selection that becomes the luminance and chrominance information attenuation rate of ratio, and this ratio very becomes attenuation module and selects whether carry out ratio through the 4th selector switch and very become decay.
First video processor is the MAX7450ESA chip, and second video processor is the MAX4389EUT-T chip, and buffer is the MAX4017ESA chip.
Compared with prior art, the present invention has following advantage:
The present invention selects each attenuation module through selecting module; Can be neatly to the combination of several kinds of evanescent modes; Simultaneously, be equipped with the selector switch that is used to regulate attenuation rate in each attenuation module, thereby great convenience be provided for composite video signal tolerance limit tolerating measure.
Description of drawings
Fig. 1 is a theory diagram of the present invention;
Fig. 2 is the circuit theory diagrams of amplitude attenuation module;
Fig. 3 is the circuit theory diagrams of high frequency attenuation module;
Fig. 4 is the circuit theory diagrams of low cut module;
Fig. 5 very becomes the circuit theory diagrams of attenuation module for ratio.
Embodiment
Below in conjunction with accompanying drawing the present invention is carried out detailed description.
As shown in Figure 1, a kind of composite video signal attenuating device, it comprises with lower module:
The amplitude attenuation module, decay when being used for luminance and chrominance information; The high frequency attenuation module is used for the decay of carrier chrominance signal; The low cut module is used for the decay of field signal envelope; Ratio very becomes attenuation module, and the ratio that is used for synchronizing signal and bright signal very becomes decay; And select module, be used to select one or more attenuation module that composite video signal is decayed.
And above-mentioned four kinds of evanescent modes can make up flexibly, are applicable to that the equipment composite video inserts the tolerance limit tolerating measure of signal.Composite video signal attenuating device includes a plurality of switches, bleeder circuit, RC circuit and video frequency processing chip and constitutes, and can select the combination of various signal attenuation patterns or various modes separately, can adjust the attenuation rate of various patterns flexibly, and is powerful.Below respectively each attenuation module and selection module principle are described.
This selection module comprises each selector switch SW1, SW2, SW3, the SW4 that is connected with each attenuation module respectively, and whether each selector switch selects corresponding attenuation module composite video signal to be decayed.
As shown in Figure 2; This amplitude attenuation module is made up of bleeder circuit and the 5th selector switch SW5; Bleeder circuit is realized the amplitude attenuation to composite video signal; The 5th selector switch SW5 is through the ratio of the various resistance values of selection with the change dividing potential drop, thus the change rate of signal attenuation, and this amplitude attenuation module selects whether to carry out amplitude attenuation through the first selector switch SW1.The amplitude signal attenuation rate can be divided into: 1 grade: decay 40%; 2 grades: decay 50%; 3 grades: decay 60%; 4 grade 70%; 5 grades: 80%.Wherein, the 5th selector switch SW5 is a rotary switch, and these grades number is through the resistance of rotation the 5th selector switch SW5 change access bleeder circuit, because resistance value changes, thereby the dividing potential drop ratio that changes bleeder circuit reaches the ratio that adjustment decays.
As shown in Figure 3; This high frequency attenuation module is made up of RC circuit and the 6th selector switch SW6; The RC circuit is realized the high frequency attenuation to composite video signal; The 6th selector switch SW6 passes through to select various capacitances with change RC circuit, thereby changes signal high frequency attenuation rate, and this high frequency attenuation module selects whether to carry out high frequency attenuation through the second selector switch SW2.The attenuation rate can be divided into: 1 grade: decay 40%; 2 grades: decay 50%; 3 grades: decay 60%; 4 grades: 70%; 5 grades: 80%.Wherein, The 6th selector switch SW6 also is a rotary switch; These grades number is through the electric capacity of rotation the 6th selector switch SW6 change access RC circuit, and capacitance changes, thereby the formation (mainly being the variation of reactance value in the RC circuit) that changes the RC circuit reaches the ratio that adjustment decays.
As shown in Figure 4; This low cut module is made up of the 2nd RC circuit and the 7th selector switch SW7; The 2nd RC circuit is realized the low cut to composite video signal; The 7th selector switch SW7 passes through to select various capacitances with change RC circuit, thereby changes signal low cut rate, and this low cut module selects whether to carry out low cut through the 3rd selector switch SW3.Low cut collapsing field signal envelope also is divided into 5 grades and decays, and the shelves number is high more, and attenuation rate is big more.
As shown in Figure 5; This ratio very becomes attenuation module and comprises the first video processor U9, the second video processor U7, buffer U6, the 8th selector switch SW8 and the 9th selector switch SW9; This first video processor U9 is connected with the second video processor U7; And realize the ratio of composite video signal is very become decay; Buffer U6 realizes the output buffers to composite video signal, and the 8th selector switch SW8 is the bright signal attenuator switch, and the 9th selector switch SW9 is used for the strange selection that becomes the luminance and chrominance information attenuation rate of ratio; The strange synchronizing signal that is used for analog video signal that becomes of ratio decays with different attenuation rates with bright signal; Attenuator adopts two-way switch to control respectively the decay of synchronizing signal and bright signal decay, and wherein the 8th selector switch SW8 bright signal of only decaying reaches adjustment bright signal attenuation rate through changing the resistance that inserts attenuator circuit.Synchronizing signal is not decayed; The 9th selector switch SW9 only decays to synchronizing signal; Reach adjustment synchronizing signal attenuation rate through changing the resistance that inserts attenuator circuit; Bright signal is not decayed, and this ratio very becomes attenuation module and selects whether to carry out ratio through the 4th selector switch SW4 and very become decay.
The first video processor U9 is the MAX7450ESA chip, and the second video processor U7 is the MAX4389EUT-T chip, and buffer U6 is the MAX4017ESA chip.
Be used for the strange selection that becomes the luminance and chrominance information attenuation rate of ratio: 1 grade: decay 10%; 2 grades: decay 30%; 3 grades: decay 50%; 4 grades: decay 60%; 5 grades: decay 70%; Be used for the strange selection that becomes the synchronizing signal attenuation rate of ratio: 1 grade: decay 10%; 2 grades: decay 30%3 grades: decay 50%; 4 grades: decay 60%; 5 grades: decay 70%.
Claims (7)
1. composite video signal attenuating device is characterized in that comprising with lower module:
The amplitude attenuation module, decay when being used for luminance and chrominance information;
The high frequency attenuation module is used for the decay of carrier chrominance signal;
The low cut module is used for the decay of field signal envelope;
Ratio very becomes attenuation module, and the ratio that is used for synchronizing signal and bright signal very becomes decay; And
Select module, be used to select one or more attenuation module that composite video signal is decayed.
2. composite video signal attenuating device according to claim 1; It is characterized in that: this selection module comprises each selector switch (SW1, SW2, SW3, SW4) that is connected with each attenuation module respectively, and whether each selector switch selects corresponding attenuation module composite video signal to be decayed.
3. composite video signal attenuating device according to claim 2; It is characterized in that: this amplitude attenuation module is made up of bleeder circuit and the 5th selector switch (SW5); Bleeder circuit is realized the amplitude attenuation to composite video signal; The 5th selector switch (SW5) is through the ratio of the various resistance values of selection with the change dividing potential drop, thus the change rate of signal attenuation, and this amplitude attenuation module selects whether to carry out amplitude attenuation through first selector switch (SW1).
4. composite video signal attenuating device according to claim 2; It is characterized in that: this high frequency attenuation module is made up of RC circuit and the 6th selector switch (SW6); The RC circuit is realized the high frequency attenuation to composite video signal; The 6th selector switch (SW6) passes through to select various capacitances with change RC circuit, thereby changes signal high frequency attenuation rate, and this high frequency attenuation module selects whether to carry out high frequency attenuation through second selector switch (SW2).
5. composite video signal attenuating device according to claim 2; It is characterized in that: this low cut module is made up of the 2nd RC circuit and the 7th selector switch (SW7); The 2nd RC circuit is realized the low cut to composite video signal; The 7th selector switch (SW7) is through selecting various capacitances changing the 2nd RC circuit, thereby changes signal low cut rate, and this low cut module is through the 3rd selector switch (SW3) selection whether carrying out low cut.
6. composite video signal attenuating device according to claim 2; It is characterized in that: this ratio very becomes attenuation module and comprises first video processor (U9), second video processor (U7), buffer (U6), the 8th selector switch (SW8) and the 9th selector switch (SW9); This first video processor (U9) is connected with second video processor (U7); And realize the ratio of composite video signal is very become decay; Buffer (U6) is realized the output buffers to composite video signal; The 8th selector switch (SW8) is the bright signal attenuator switch, and the 9th selector switch (SW9) is used for the strange selection that becomes the luminance and chrominance information attenuation rate of ratio, and this ratio very becomes attenuation module and whether carries out ratio through the 4th selector switch (SW4) selection and very become decay.
7. composite video signal attenuating device according to claim 6 is characterized in that: first video processor (U9) is the MAX7450ESA chip, and second video processor (U7) is the MAX4389EUT-T chip, and buffer (U6) is the MAX4017ESA chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101932784A CN101764985B (en) | 2009-10-23 | 2009-10-23 | Composite video signal attenuating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101932784A CN101764985B (en) | 2009-10-23 | 2009-10-23 | Composite video signal attenuating device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101764985A CN101764985A (en) | 2010-06-30 |
| CN101764985B true CN101764985B (en) | 2012-05-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009101932784A Expired - Fee Related CN101764985B (en) | 2009-10-23 | 2009-10-23 | Composite video signal attenuating device |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3938179A (en) * | 1974-09-16 | 1976-02-10 | Rca Corporation | Comb filter for video processing |
| CN1822654A (en) * | 2005-02-14 | 2006-08-23 | 三洋电机株式会社 | On-screen display circuit |
| CN101043203A (en) * | 2006-03-24 | 2007-09-26 | 夏普株式会社 | Variable gain amplifier |
-
2009
- 2009-10-23 CN CN2009101932784A patent/CN101764985B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3938179A (en) * | 1974-09-16 | 1976-02-10 | Rca Corporation | Comb filter for video processing |
| CN1822654A (en) * | 2005-02-14 | 2006-08-23 | 三洋电机株式会社 | On-screen display circuit |
| CN101043203A (en) * | 2006-03-24 | 2007-09-26 | 夏普株式会社 | Variable gain amplifier |
| JP2007259297A (en) * | 2006-03-24 | 2007-10-04 | Sharp Corp | Variable gain amplifier and communication equipment provided with the variable gain amplifier |
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| Publication number | Publication date |
|---|---|
| CN101764985A (en) | 2010-06-30 |
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Address after: Kezhu road high tech Industrial Development Zone, Guangzhou city of Guangdong Province, No. 233 510670 Patentee after: Wei Chong group Limited by Share Ltd Address before: 510663 Guangzhou province high tech Industrial Development Zone, Guangdong, Cai road, No. 6, No. Patentee before: Guangdong Weichuangshixun Science and Technology Co., Ltd. |
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Granted publication date: 20120509 Termination date: 20181023 |