PURPOSE: To apply picture processing for signals of an exclusive monitor and a TV receiver for home use by means of the same computer by extracting RF modulation from a personal computer main body to a separate case and incorporating the case with a switch box.

CONSTITUTION: A video output 5 of a personal computer is a composite signal and few home use TV receiver 9 has an input terminal for the signal. Then it is difficult to display a picture on the home use TV receiver 9 by using a signal being an output of the personal computer. Thus, the signal of the personal computer output is inputted, the composite signal is inputted to an RF modulator 1 by using a modulator 1, the result is outputted to the TV9 through a switch 3 and the output is utilized as a TV signal 8. Similarly, a sound modulator 2 inputs an output6 of the personal compute to the RF modulator receiving the composite signal of the personal computer and the result is outputted to the TV9 through the switch 3. When the user changes over the personal computer into the general TV broadcast reception, it can be used by changing over the switch 3 to the position of antenna side.