1. Technical Field
The present disclosure relates to video apparatus, and particularly to a video apparatus and a video circuit for improving video signal quality.
2. Description of the Related Art
Referring to
The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawing, like reference numerals designate corresponding parts throughout the several views.
Referring to
The video circuit 100 includes a display circuit 40 and a compensation circuit 50. The display circuit 40 is connected between an input port and an output port of the compensation circuit 50. When the video apparatus 200 is switched into a video input mode in response to a user's operation, the display circuit 40 receives video signals via the interface unit 30 which is generated in response to the user's operation and has been filtered out some video signals. The compensation circuit 50 adds a predetermined amount of direct current to the video signal filtered by the display circuit 40 to compensate the video signals, thereby reduces the video signal distortion.
Referring to
In the embodiment, the display circuit 40 includes a capacitor EC1, a video switcher 41, a resistor R39, a resistor R42, a capacitor C46, and a video driver 42. The capacitor EC1, the video switcher 41, the resistor R39, and the capacitor C46 are connected between the first port 1 and the video driver 42 in series. The resistor R42 is connected between a junction where the capacitor C46 is connected to the resistor R39 and ground.
The video switcher 41 is configured for generating a switch signal for switching the video apparatus 200 into the video mode in response to the user's operation. The video switcher 41 is connected to a power supply which provides a U1 volts, such as 3.3 V. A permitted voltage value range of the video switcher 41 is predetermined, such as 0 V-3.3 V. The direct current component of the video signal is filtered when the video signal flows through the interface unit 30 and the capacitor EC1, and the alternating current component of the video signal flows to the video switcher 41. The video switcher 41 blocks the alternating current whose voltage values do not fall in the permitted voltage range of the video switcher 41. For example, the alternated current whose amplitude is greater than 0 flows to the video driver 42 through the video switcher 41 via the resistor R39 and the capacitor C46, and the alternated current whose amplitude is smaller than 0 is blocked by the video switcher 41.
In the embodiment, the compensation circuit 50 includes a microcontroller 51, a resistor R1, a triode Q1, a resistor R2, and a diode D1. The emitter of the triode Q1 is connected to an output port (not shown) of the video switcher 41, the base of the triode Q1 is connected to the microcontroller 51, and the collector of the triode Q1 is connected to an input port of the video switcher 41 via the resistor R2 and the diode D1.
The microcontroller 51 generates a signal in response to a video mode switch signal generated by the user's operation on an input unit 60 to turn on the triode Q1 via the resistor R1. Thereby, an amount of direct current UV calculated by a formula is put into the video switcher 41. The formula is: UV=(U1−UD)×(R39+R42)/(R2+R39+R42). UD is the voltage value of the diode D1.
The compensation circuit 50 adds the direct current value UV to the video signal flowing through the video switcher 41, and the video signal compensated by the compensation circuit 50 flows to the video driver 42 via the capacitor C46. The video driver 42 generates a signal according to the compensated video signal, and displays a corresponding video image on the display screen 20 according to the signal.
It is understood that the present disclosure may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the disclosure is not to be limited to the details given herein.
Number | Date | Country | Kind |
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201210107557.6 | Apr 2012 | CN | national |