There are two different resolution sizes for high definition televisions (HDTV): 720 lines of horizontal resolution is the lowest and 1080 is the highest. If you are running an HD cable receiver to an HD 720 television, it is possible to set the cable receiver to a higher resolution than the TV. Although this does not improve the picture quality, it does set the receiver up for the possibility of connecting a 1080 TV in the future.
Power on the 720 HDTV and the high definition cable receiver.
Press the "Menu" button on the receiver's remote control. Once the main menu screen appears on the television, select "Options."
Choose "Aspect Ratio" from the list of options presented on the screen.
Select "1080" as the HD resolution you want the cable receiver set to. Press "OK" and exit out of the menu. The image on the screen zooms in and doubles the size of the content on the 720 screen (due to the receiver attempting to produce the 1080 lines of resolution).
Press the "Zoom" button on the 720 TV's remote control. Continue pressing the button until the entire picture fits into the viewing area.
Things You'll Need
HD cable receiver
HD 720 TV