Signal processing device, liquid crystal display, system for testing liquid crystal display and method of driving the liquid crystal display

A liquid crystal display comprising:

• an external signal provider providing an external image signal, an external clock signal and an external driving voltage and outputting a check signal to the outside;
• a memory unit storing reference data corresponding to the external clock signal;
• a signal-processing unit receiving the external image signal and providing an internal image signal and receiving the external clock signal and providing an internal clock signal;
• an image display unit displaying predetermined images corresponding to the internal image signal in response to the internal clock signal;
• a driving voltage generator receiving the external driving voltage and generating a plurality of internal driving voltages driving the image display unit;
• and
• a checking unit comparing the external clock signal with the reference data and feeding back the check signal representing whether the external clock signal is inputted to the external signal provider without any error, to the external signal provider according to the result of the comparison.

A system for testing a liquid crystal display comprising:

• a test signal provider providing a test external image signal, a test external clock signal and a test driving voltage;
• and
• the liquid crystal display to be tested comprising:
• a memory unit storing reference data corresponding to the test external clock signal;
• a signal-processing unit receiving the test external image signal and providing a test internal image signal and receiving the test external clock signal and providing a test internal clock signal;
• an display unit displaying predetermined images corresponding to the test internal image signal in response to the test internal clock signal;
• and
• a checking unit comparing the test external clock signal with the reference data and feeding back the check signal representing whether the test external clock signal is inputted to the liquid crystal display without any error, to the test signal provider according to the result of the comparison,
• wherein the liquid crystal display to be tested is driven by the test driving voltage.