LEVEL SHIFT CIRCUIT FOR ANALOG SIGNAL AND SIGNAL WAVEFORM GENERATOR USING SAME

摘要

PROBLEM TO BE SOLVED: To reduce a circuit area by reducing the power consumption of a signal waveform generator generating a base band signal in digital communication. SOLUTION: An analog signal Vdac outputted from a D/A converter 11 is analog-added with level shift voltage by a first signal level shifter 12 to be a base band signal Vls. Since the first signal level shifter 12 is provided with the same level shift characteristics with a second signal level shifter 15, level shift voltage becomes the potential difference between a signal ground potential Vsg and a signal center potential Vm by the feedback control of an arithmetic amplifier 16. Since a signal ground potential deciding circuit 13 is provided with a function of adjusting the potential Vsg in accordance with an offset voltage adjusting signal 17, a D/A converter 11 is not needed to be provided with a current cell for adjusting offset voltage.