Display device with function of converting resolution

A display device receives an image data from an image-data generating apparatus generating image-data, convert, on the basis of a horizontal synchronizing signal and a vertical synchronizing signal of the received image data, a resolution and a pixel clock of the image data to values that are registered in advance and supported by a monitor, and then output the image data to the monitor, the display device comprising:

• a input interface that is connectable through an analog Red Green Blue (RGB) cable to the image-data generating apparatus;
• a video-signal control circuit that converts the resolution and the pixel clock of the image data,
• the video-signal control circuit comprises of an analog-digital converting unit which converts an analog image signal inputted through the input interface into a digital image signal and a controller that implements scaling processing to convert resolution of a digital image-data represented by the digital image signal to a resolution and a pixel clock which are supported by the monitor;
• a table registering correspondences between values of the horizontal synchronizing signal and values of the vertical synchronizing signal, and values of the resolution and values of the pixel clock of the image data that respectively correspond to the respective correspondences;
• and
• a control unit that (i) detects the horizontal and vertical synchronizing signals of the image data, (ii) operates to present a data input window on a screen when a correspondence between the detected horizontal and vertical synchronizing signals is not registered in the table, and take a value of the resolution and a value of the pixel clock inputted through the data input window as a value of the resolution and a value of the pixel clock of the image data, and (iii) makes the video-signal control circuit convert the resolution and the pixel clock of the image data from the resolution and the pixel clock inputted through the data input window to the resolution supported by the monitor, and output the image data to the monitor at the converted resolution and pixel clock and;
• the analog-digital converting unit of the video-signal control circuit converts the analog image signal inputted through the input interface into the digital image signal according to the inputted resolution and the pixel clock into the digital image signal, then the controller of the video-signal control circuit implements scaling processing to convert the resolution of the digital image-data to the resolution supported by the monitor.