CN201039332Y - Color system selection circuit and TV set with this selection circuit - Google Patents
Color system selection circuit and TV set with this selection circuit Download PDFInfo
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- CN201039332Y CN201039332Y CNU2007200189663U CN200720018966U CN201039332Y CN 201039332 Y CN201039332 Y CN 201039332Y CN U2007200189663 U CNU2007200189663 U CN U2007200189663U CN 200720018966 U CN200720018966 U CN 200720018966U CN 201039332 Y CN201039332 Y CN 201039332Y
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Abstract
The utility model discloses a color mode selecting circuit and a television with the color mode selecting circuit, comprising a radio frequency signal outputting terminal and an acoustic surface wave filter, wherein, the radio frequency signal outputting terminal is connected with one inputting end of the acoustic surface wave filter; moreover, the radio frequency signal outputting terminal is connected with a cathode of a switch diode; an anode of the switch diode is connected with the other inputting end of the acoustic surface wave filter and is grounded through a gating circuit of a switch circuit. The controlling end of the switch circuit receives the controlling signal outputted by a processor; the anode of the switch diode is connected with a first power circuit. The inputting end of the acoustic surface wave filter is provided with a simple peripheral circuit which only occupies one I/O interface of the CPU, so the utility model can realize the selection of PAL, NTSC and SECAM. With simple structure and subtle design, the color mode selecting circuit has strong commonality and expansibility.
Description
Technical field
The utility model belongs to the signal selecting circuit technical field, and specifically, the standard that relates to a kind of colour signal is selected circuit.
Background technology
Existing color television set all has PAL, NTSC and three kinds of S-SYSTEMs of SECAM, when reality is used, need select to use corresponding decoder to decode according to customer requirements.At present, the TV set circuit that has is before the intermediate-freuqncy signal IF of tuner output enters the sound table, need to select respectively the colour signal of various standards through complicated circuit, perhaps need to use two-way or three tunnel control signals to select the S-SYSTEM of input signal respectively, though circuit theory is very simple, but the components and parts number that is to use is more, need take the more I/O mouth of CPU, causes the anxiety of cpu port resource.Therefore, how to design a kind of S-SYSTEM simple in structure, that take the few and highly versatile of cpu port resource and select circuit, just become present television set and make one of subject matter that industry needs to be resolved hurrily.
Summary of the invention
Goal of the invention of the present utility model is to provide a kind of novel S-SYSTEM to select circuit, to solve existing S-SYSTEM selecting circuit structure complexity, need take the problem of the more port resource of CPU.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of S-SYSTEM is selected circuit and is had the television set of described selection circuit, comprise radiofrequency signal lead-out terminal and SAW (Surface Acoustic Wave) filter, wherein, described radiofrequency signal lead-out terminal connects wherein one road input of SAW (Surface Acoustic Wave) filter on the one hand, the negative electrode that connects a switching diode on the other hand, the anode of described switching diode connects another road input of SAW (Surface Acoustic Wave) filter, and the gating switch ground connection of passing through a switching circuit, the control signal of the control end receiving processor output of described switching circuit; Anode at described switching diode is connected with first power circuit.
In order to allow the signal of radiofrequency signal lead-out terminal output enter Surface Acoustic Wave Filter selectively, negative electrode at described switching diode is connected with the second source circuit, when the gating switch of described switching circuit disconnected, first power circuit affacted the anode voltage of described switching diode and the second source circuit function is higher than described switching diode to the difference of the cathode voltage of described switching diode conduction voltage drop.
Include first resistance and first DC power supply in described first power circuit, described first DC power supply connects the anode of described switching diode by first resistance; Include second resistance and second DC power supply in described second source circuit, described second DC power supply connects the negative electrode of described switching diode by second resistance.
Described first DC power supply and second DC power supply are same power supply; The resistance of described first resistance is less than the resistance of second resistance.
In order to simplify circuit structure, described switching circuit adopts a NPN type triode to realize, the control signal of the base stage receiving processor output of described triode, and collector electrode connects the anode of described switching diode, grounded emitter.
Compared with prior art, advantage of the present utility model and good effect are: the utility model is by the simple peripheral circuit of input design in SAW (Surface Acoustic Wave) filter, only need take the road I/O mouth of CPU, can realize the selection of PAL, NTSC and three kinds of S-SYSTEMs of SECAM.S-SYSTEM selecting circuit structure of the present utility model is simple, design is ingenious, have very strong versatility and autgmentability, greatly reduce system cost, effectively solve existing S-SYSTEM selecting circuit structure complexity, need take the problem of the more port resource of CPU.
Description of drawings
Fig. 1 selects the schematic diagram of circuit for the utility model S-SYSTEM.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is described in further detail.
The utility model provides a kind of novel S-SYSTEM to select circuit in order to solve S-SYSTEM selecting circuit structure complexity in the prior art, need to take the problem of the more port resource of CPU, comprises radiofrequency signal lead-out terminal and SAW (Surface Acoustic Wave) filter; Described radiofrequency signal lead-out terminal can be the tuner of television set, output intermediate-freuqncy signal IF; But can also be the lead-out terminal of other received RF signals such as set-top box.Wherein, described radiofrequency signal lead-out terminal connects wherein one road input of SAW (Surface Acoustic Wave) filter on the one hand, the negative electrode that connects a switching diode on the other hand, the anode of described switching diode connects another road input of SAW (Surface Acoustic Wave) filter, and the gating switch ground connection of passing through a switching circuit, the control signal of the control end receiving processor of described switching circuit output is according to the conducting and the cut-off state of the described switching circuit of high-low level State Control of control signal.When described switching circuit conducting, the gating switch closure, the plus earth of switching diode, diode ends, and radiofrequency signal is only imported wherein one road input of SAW (Surface Acoustic Wave) filter.Anode at described switching diode is connected with first power circuit, when described switching circuit ends, control described switching diode conducting, radiofrequency signal is input to the two-way input of SAW (Surface Acoustic Wave) filter simultaneously, whether SAW (Surface Acoustic Wave) filter has signal input to judge the standard of input signal according to its two-way input simultaneously, thereby selects different bandwidth to come filtering.
Embodiment one, and Fig. 1 shows wherein a kind of circuit connection structure of the present utility model, and wherein, IF is the intermediate-freuqncy signal of tuner output, and the DC power supply VCC and first resistance R 2 are formed first power circuit, connect wherein one road input IN-of SAW (Surface Acoustic Wave) filter.The DC power supply VCC and second resistance R 1 are formed the second source circuit, connect another road input IN+ of SAW (Surface Acoustic Wave) filter.Between two-way input IN-, the IN+ of SAW (Surface Acoustic Wave) filter, be connected with switching diode D1, intermediate-freuqncy signal IF connects the input IN+ of SAW (Surface Acoustic Wave) filter, the input IN-of SAW (Surface Acoustic Wave) filter connects the collector electrode as the NPN type triode Q1 of switch element, the grounded emitter of triode Q1, and connect the base stage of triode Q1 by biasing resistor R4, the base stage of described triode Q1 is by resistance R 3, through the I/O mouth of signal drive circuit connecting circuit equipment primary processor CPU, receive the high-low level control signal SAW1 of CPU output.
Its circuit working principle is as follows: when SAW1 is high level, dividing potential drop by base resistance R3 and biasing resistor R4 can make the A point voltage for high, thereby make triode Q1 conducting, so the B point is low level to ground, at this moment switching diode D1 ends, intermediate-freuqncy signal IF can only enter SAW (Surface Acoustic Wave) filter by the IN+ pin, and the IN-pin is equivalent to ground connection.At this moment the standard of Xuan Zeing is Phase Alternation Line system or Sequential Color and Memory system.When control signal SAW1 was low level, the A point also was low, so triode Q1 ends.Because the resistance of first resistance R 2 is less than the resistance of second resistance R 1, therefore, the B point voltage is higher than the C point, can make the conducting voltage of the pressure reduction of 2 of BC by the resistance of suitably choosing R1 and R2 greater than switching diode D1, thereby make diode D1 conducting, so intermediate-freuqncy signal IF can enter the sound table simultaneously by IN+ pin and IN-pin.At this moment the standard of Xuan Zeing is a TSC-system.Whether SAW (Surface Acoustic Wave) filter has signal input just can judge the standard of input signal by its IN+ and IN-pin simultaneously, thereby selects different bandwidth to come filtering, and puts in the chip in outputing to by its output VIF1 and VIF2.Phase Alternation Line system and Sequential Color and Memory system in put chip internal and discern by signal format.This is because the signal of Phase Alternation Line system and N system all is that the brightness in the signal and two every provisional capitals of color difference signal are transmitted when transmitting, but Sequential Color and Memory system all transmit the every frame of luminance signal when transmitting, and two color difference signals transmit successively.Therefore, by judging that color difference signal just can differentiate Phase Alternation Line system and Sequential Color and Memory system.
Putting the selection circuit that does not need before the chip again three kinds of standards in entering like this designs respectively, only just can realize the selection of three kinds of standards with a simple circuit and control signal, circuit structure is simple, novel in design, can promote the use of in multiple electronic products such as television set, set-top box.
Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.
Claims (10)
1. a S-SYSTEM is selected circuit, comprise radiofrequency signal lead-out terminal and SAW (Surface Acoustic Wave) filter, it is characterized in that: described radiofrequency signal lead-out terminal connects wherein one road input of SAW (Surface Acoustic Wave) filter on the one hand, the negative electrode that connects a switching diode on the other hand, the anode of described switching diode connects another road input of SAW (Surface Acoustic Wave) filter, and the gating switch ground connection of passing through a switching circuit, the control signal of the control end receiving processor output of described switching circuit; Anode at described switching diode is connected with first power circuit.
2. S-SYSTEM according to claim 1 is selected circuit, it is characterized in that: the negative electrode at described switching diode is connected with the second source circuit, when the gating switch of described switching circuit disconnected, first power circuit affacted the anode voltage of described switching diode and the second source circuit function is higher than described switching diode to the difference of the cathode voltage of described switching diode conduction voltage drop.
3. S-SYSTEM according to claim 2 is selected circuit, and it is characterized in that: include first resistance and first DC power supply in described first power circuit, described first DC power supply connects the anode of described switching diode by first resistance; Include second resistance and second DC power supply in described second source circuit, described second DC power supply connects the negative electrode of described switching diode by second resistance.
4. S-SYSTEM according to claim 3 is selected circuit, and it is characterized in that: described first DC power supply and second DC power supply are same power supply; The resistance of described first resistance is less than the resistance of second resistance.
5. select circuit according to arbitrary described S-SYSTEM among the claim 1-4, it is characterized in that: described switching circuit is a NPN type triode, the control signal of the base stage receiving processor output of described triode, collector electrode connects the anode of described switching diode, grounded emitter.
6. one kind has the television set that S-SYSTEM is selected circuit, described S-SYSTEM selects circuit to comprise radiofrequency signal lead-out terminal and SAW (Surface Acoustic Wave) filter, it is characterized in that: described radiofrequency signal lead-out terminal connects wherein one road input of SAW (Surface Acoustic Wave) filter on the one hand, the negative electrode that connects a switching diode on the other hand, the anode of described switching diode connects another road input of SAW (Surface Acoustic Wave) filter, and the gating switch ground connection of passing through a switching circuit, the control signal of the control end receiving processor output of described switching circuit; Anode at described switching diode is connected with first power circuit.
7. television set according to claim 6, it is characterized in that: the negative electrode at described switching diode is connected with the second source circuit, when the gating switch of described switching circuit disconnected, first power circuit affacted the anode voltage of described switching diode and the second source circuit function is higher than described switching diode to the difference of the cathode voltage of described switching diode conduction voltage drop.
8. television set according to claim 7 is characterized in that: include first resistance and first DC power supply in described first power circuit, described first DC power supply connects the anode of described switching diode by first resistance; Include second resistance and second DC power supply in described second source circuit, described second DC power supply connects the negative electrode of described switching diode by second resistance.
9. television set according to claim 8 is characterized in that: described first DC power supply and second DC power supply are same power supply; The resistance of described first resistance is less than the resistance of second resistance.
10. according to arbitrary described television set among the claim 6-9, it is characterized in that: described switching circuit is a NPN type triode, the control signal of the base stage receiving processor output of described triode, collector electrode connects the anode of described switching diode, grounded emitter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200189663U CN201039332Y (en) | 2007-02-13 | 2007-02-13 | Color system selection circuit and TV set with this selection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200189663U CN201039332Y (en) | 2007-02-13 | 2007-02-13 | Color system selection circuit and TV set with this selection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201039332Y true CN201039332Y (en) | 2008-03-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200189663U Expired - Fee Related CN201039332Y (en) | 2007-02-13 | 2007-02-13 | Color system selection circuit and TV set with this selection circuit |
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| CN (1) | CN201039332Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101431636B (en) * | 2008-12-04 | 2014-04-02 | 康佳集团股份有限公司 | Television set tuner with clock output |
-
2007
- 2007-02-13 CN CNU2007200189663U patent/CN201039332Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101431636B (en) * | 2008-12-04 | 2014-04-02 | 康佳集团股份有限公司 | Television set tuner with clock output |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080319 Termination date: 20110213 |