CN1154037A - Circuit for mixing of video and OSD signals - Google Patents
Circuit for mixing of video and OSD signals Download PDFInfo
- Publication number
- CN1154037A CN1154037A CN 96112440 CN96112440A CN1154037A CN 1154037 A CN1154037 A CN 1154037A CN 96112440 CN96112440 CN 96112440 CN 96112440 A CN96112440 A CN 96112440A CN 1154037 A CN1154037 A CN 1154037A
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- China
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- circuit
- osd
- signal
- video
- analog switch
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Abstract
When OSD information and video pictures are displayed on a single screen at the same time, it is convenient for a viewer that both signals have the same brightness. To achieve this, both OSD signals and video signals must have the same DC voltage level. To provide both the OSD signal and the video signal with such a common DC voltage level, a clamping circuit between both lines is provided. In the embodiment the clamping circuit is realized by a combination of a voltage divider, a pair of diodes and a capacitor, but any other commercially available clamping circuit can be used.
Description
The present invention relates to a kind of circuit that is used for mixed video signal and OSD (showing on the screen) signal, these two kinds of signals will be simultaneously displayed on the single screen.
The main purpose of known OSD blender be with some character for example a menu system be integrated in original vision signal and go.Therefore, the overlapping image that character is arranged above display unit shows.And this OSD blender can also only be presented at the osd information of no any image on the background.The application of this OSD blender is VCR and television set.
The problem that known OSD blender faces is when showing osd information and video image on single screen, can not always guarantee to show this two kinds of signals with identical brightness that this may be inconvenient for the beholder.And if force osd signal and vision signal to have identical dc voltage, then can realize this same brightness.
Therefore, the purpose of this invention is to provide a kind of circuit that is used for mixed video signal and osd signal, this circuit provides osd signal and vision signal with identical DC level.
The present invention comprise a kind of be used to mix will be on single screen the circuit of video signal displayed and osd signal, it is characterized in that this circuit comprises a clamp circuit that these two signals all is clamped to a public predetermined reference dc voltage.
This clamp circuit comprises one by a pair of resistor, a capacitor and two voltage dividers that diode is formed in addition.An available analog switch is realized switching between vision signal and the osd signal.The most handy high-speed cmos of this analog switch constitutes and controlled by a logic device.
In addition, determine to insert the position of OSD character by the control signal that is input to analog switch.
The present invention has provided a kind of ball bearing made using that shows osd signal and vision signal with identical brightness on same screen simultaneously.Clamp circuit and nonessential combination realization by above-mentioned parts also can replace with any clamp circuit that other is suitable for.
Referring now to accompanying drawing the preferred embodiments of the present invention are described.
Fig. 1 shows the circuit theory diagrams of an OSD blender preferred embodiment
OSD blender shown in Figure 1 has an analog switch 1, and a clamp circuit 2 between video signal cable 3 and osd signal line 4.
In the following description, the preferred value of used unit provides in bracket.It is emphasized that the present invention has more than is limited to the parts that have this preferred value.
In video signal cable 3 and osd signal line 4, before the clamp circuit 2 that holding wire 3 and 4 is clamped to the public direct-current level, provide a capacitor C (10 μ F).Analog switch 1 is by a logic control signal 5 controls, and this logic control signal is to produce in the logical circuit (not shown) of a certain picture microprocessor one class.The switch of logical signal 5 decision logic switches 1 is connected to video signal cable 3 or is connected to osd signal line 4, and this two paths of signals all is input in this analog switch 1.Usually realize analog switch 1 with high-speed cmos analog switch, for example 74HC4053.Clamp circuit 2 usefulness one voltage divider realizes that this voltage divider is made up of resistor R 1 (3.3k Ω), R2 (3.9k Ω), capacitor C1 (100 μ F) and two diode D1, D2 (1SS181), wherein R2 ground connection and R1 receive power source voltage Vcc (+5V) on.
Claims (6)
1, be used for mixing will be on single screen the circuit of video signal displayed (3) and osd signal (4), it is characterized in that: this circuit comprises a clamp circuit (2) that two signals (3,4) is clamped to a public predetermined reference dc voltage.
2, circuit as claimed in claim 1, wherein clamp circuit (2) comprises a voltage divider of being made up of a pair of resistor (R1, R2), a capacitor (C1) and two diodes (D1, D2).
3, circuit as claimed in claim 1 or 2 comprises that also is used for an analog switch (1) that switches between vision signal (3) and osd signal.
4, each described circuit in the claim as described above, wherein analog switch (1) is made of a high-speed cmos.
5, the described circuit of one of claim as described above, wherein analog switch (1) is subjected to the control of a logic device.
6, the described circuit of one of claim as described above, the position of wherein determining to insert the OSD character by the control signal that is input to analog switch (1) (5).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN 96112440 CN1154037A (en) | 1995-11-09 | 1996-10-18 | Circuit for mixing of video and OSD signals |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9523011/6 | 1995-11-09 | ||
CN 96112440 CN1154037A (en) | 1995-11-09 | 1996-10-18 | Circuit for mixing of video and OSD signals |
Publications (1)
Publication Number | Publication Date |
---|---|
CN1154037A true CN1154037A (en) | 1997-07-09 |
Family
ID=5121459
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN 96112440 Pending CN1154037A (en) | 1995-11-09 | 1996-10-18 | Circuit for mixing of video and OSD signals |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN1154037A (en) |
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1996
- 1996-10-18 CN CN 96112440 patent/CN1154037A/en active Pending
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Legal Events
Date | Code | Title | Description |
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C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
WD01 | Invention patent application deemed withdrawn after publication |