PURPOSE: To attain easy to see channel display with large display by applying DC conversion to a display data corresponding to a channel, synthesizing the result into a sawtooth wave for display and forming a video signal including the channel display based thereupon.

CONSTITUTION: Display data D0∼D5 weighted depending on the channel are inputted to a D/A converter comprising resistors R0∼R5. Weighting is applied to the resistors according to the weighting of input data. A common terminal side of the resistors is connected to a current mirror circuit (comprising transistors Q1, Q2) and a DC voltage changed linearly is obtained across a resistor R7 accoding to the display data to be D/A-converted. On the other hand, a sawtooth wave signal of vertical period is inputted from a terminal 157, and the signal voltage is divided and applied to a monostable multivibrator 161. As a result, a signal superimposed with a DC voltage and a sawtooth wave generated at a D/A converter is applied to the monostable multivibtator 161, whose output is applied to a video amplifier circuit from a terminal 5c.