CN104952382A - Transmission before-after comparison device for images of liquid crystal display television - Google Patents

Abstract

The invention provides a transmission before-after comparison device for the images of a liquid crystal display television. The device comprises a plurality of XOR gate chips and OR gate chips, wherein the first input ends of the XOR gate chips are used for receiving the original signals output by a liquid crystal display, the second input ends of the XOR gate chips are used for receiving the terminal signals obtained by transmitting the original signals through LVDS; the original signals and the terminal signals are connected to the first input ends and the second input ends in a manner of one-to-one correspondence; the output ends of the XOR gate chips are used for providing output signals; the input ends of the OR gate chips are used for receiving the signals of the output ends of the XOR gate chips; the output ends of the OR gate chips are used for providing output signals.

Description

Comparison device before and after LCD TV image transmission

Technical field

The present invention relates to LCD TV and liquid crystal display detection technique field, particularly relate to comparison device before and after a kind of LCD TV image transmission.

Background technology

In the digital signal that liquid crystal display device driving panel exports, except comprising RGB data signal, also comprise the signals such as row is synchronous, field synchronization, pixel clock, wherein the highest frequency of pixel clock signal can more than 28MHz.Adopt TTL interface, message transmission rate is not high, and transmission range is shorter, and electromagnetism interference (EMI) ability is also poor, can affect to RGB data; In addition, TTL multichannel data signal adopts the mode of winding displacement to transmit, and whole winding displacement quantity reaches tens tunnels, not only connects inconvenience, and is not suitable for the trend of ultrathin.Adopt LVDS output interface transmission data, these problems can be made to be readily solved, realize the transmission of the two-forty of data, low noise, remote, pin-point accuracy.So, what is LVDS output interface? LVDS is a kind of technology of Low Voltage Differential Signaling interface.It is NS company of the U.S. is overcome a kind of digital signal transmission mode developed with shortcomings such as power consumption during Transistor-Transistor Logic level mode transmission broadband high code rate data are large, EMI electromagnetic interference (EMI) is large.LVDS transmits supporting rate and is generally approximately 77MHZ at 155Mbps() more than.LVDS is a kind of difference signal technique of the low amplitude of oscillation, it make signal can difference PCB line to or balanced cable on the speed rates of hundreds of Mbps, its low pressure amplitude and low current driver output achieve low noise and low-power consumption.Image data can be transferred to liquid crystal screen display from master control by LVDS interface.

At present, when the digital signal before and after liquid crystal display device driving panel (also known as master control borad) transmission is compared, be that operating personnel's Non-follow control telepilot is to carry out the switching of board under test passage.Then the picture signal of each passage needs to link on display panels artificially to judge that whether the signal that image exports is identical with the signal of input by human eye, but also need a large amount of detecting instrument to detect the situation of change of electric current and voltage.All differentiations are all that the knowledge of artificial idea is used as criterion, reliability and stability are not guaranteed, therefore traditional detection method needs the intervention completely of operating personnel just can complete in test process, and it is long to detect the time spent, so not only cause expending of a large amount of time and human and material resources, and testing efficiency is very low, this just requires a kind of automatization test system, to improve or to avoid above-mentioned defect.

Summary of the invention

For the problems referred to above, object of the present invention is mainly to provide comparison device before and after a kind of LCD TV image transmission, can compare simple and reliablely, save man power and material to exporting data with the data after LVDS transmits.

For achieving the above object, the invention provides comparison device before and after a kind of LCD TV image transmission, this device comprises:

Some XOR gate chips, its first input end is used for the original signal that receiving liquid crystal display exports, its second input end is for receiving the terminal signaling of original signal after LVDS transmission, original signal and terminal signaling access first input end and the second input end one to one, and described XOR gate chip output is used for providing output signal;

Or door chip, its input end receives the signal of XOR gate chip output, and described or door chip output is used for providing output signal.

Compared to prior art, comparison device before and after LCD TV image transmission of the present invention, signal before and after LVDS transmission is compared, adopt XOR gate chip, comparison is by turn carried out to the signal before and after transmission, and by the result access that exports or the input end of door chip, detect or the output end signal of door chip, whether the signal before judging the signal after transmitting and transmitting is identical.

[accompanying drawing explanation]

Fig. 1 is the true value chart of logic XOR gate basic operation.

Fig. 2 is the circuit theory diagrams of comparison device before and after LCD TV image transmission of the present invention.

[embodiment]

Below, by reference to the accompanying drawings, specific embodiments of the invention are elaborated:

Be illustrated in figure 1 the basic operation true value chart of logic XOR gate, given input (V3 is indicated in figure, the function of partial sum gate V4), the relation of output end signal and input end signal as can be seen from the table, from this table, only have the signal of two input ends equal, namely during V3=V4, the signal that output terminal exports is zero, can determine that whether the original signal that liquid crystal display device driving panel exports is consistent with the terminal data signal after LVDS transmission according to this principle according to output end signal.

Because the physical arrangement of display follows RGB, RGB is the color mode on basis, represents spectrum, because red, green, blue respectively accounts for 8 scale-of-two, totally 24, when the rgb signal therefore exported liquid crystal display device driving panel carries out comparison before and after transmission, can compare by turn to 24 signals.

Be illustrated in figure 2 the circuit theory diagrams of Comparison Circuit before and after invention LCD TV image transmission, comprise some XOR gate chips 1 and one or a chip 2, the output terminal of described some XOR gate chips 1 connects or the input end of door chip 2 respectively, the first input end V1 of described XOR gate chip 1 is used for the original signal of receiving liquid crystal display output, its second input end V2 is for receiving the terminal signaling of original signal after LVDS transmission, every original signal and this terminal signaling access first input end and the second input end one to one, the signal that the output terminal of described XOR gate chip 1 exports all accesses or the input end of door chip 2, computing is carried out to the output signal of XOR gate chip 1, the output signal V of detection or door chip 1.From XOR computing truth table Fig. 1, if the signal that the first input end V1 of XOR gate chip 1 and the second input end V2 receives is equal, the signal that then XOR gate chip 1 exports is zero, or the result after door chip 2 calculating is zero, otherwise, if a wherein Signal transmissions inconsequent, signal then through XOR gate chip 1 output is non-vanishing, or door operation result is also non-vanishing, therefore, by to detect or whether whether the output terminal V signal of door chip 2 be zero consistent to determine the terminal data signal of original signal after transmitting through LVDS that liquid crystal display device driving panel exports.If V is zero, then illustrate liquid crystal display device driving panel export original signal with through LVDS transmission after terminal data signal consistent, otherwise, illustrate the original signal that liquid crystal display device driving panel exports and through LVDS transmit after terminal data signal inconsistent.

By reference to the accompanying drawings the specific embodiment of the present invention and embodiment are elaborated above, but the present invention is not limited to the above-described embodiment and examples, in the ken that those skilled in the art possess, can also make a variety of changes without departing from the inventive concept of the premise.

Claims (1)

1. a comparison device before and after LCD TV image transmission, is characterized in that comprising:

Some XOR gate chips, its first input end is used for the original signal that receiving liquid crystal display exports, its second input end is for receiving the terminal signaling of original signal after LVDS transmission, original signal and terminal signaling access first input end and the second input end one to one, and described XOR gate chip output is used for providing output signal;

Or door chip, its input end receives the signal of XOR gate chip output, and described or door chip output is used for providing output signal.