CAPACITY TYPE CONVERTER

摘要

PURPOSE:To compensate nonlinearity effectively with simple constitution by controlling a set voltage according to the capacities of a couple of variable capacitors. CONSTITUTION:The 1st - the 3rd pulse width signals with duty ratios corresponding to the capacities of the couple of variable capacitors C1 and C2 and a reference capacitor C3 are outputted from a capacity pulse width converting circuit C/P and switches SW1-SW5 are controlled by those pulse width signals. The switch SW3 intermits a set voltage Vr applied through the resistance R4 and the switch SW4 intermits the set voltage Vr applied through the resistance R5; and the switch SW5 intermits the inverted voltage -Vr of an inverting amplifier IA2 applied with the set voltage Vr through a variable resistance R6. Then, an integration circuit IC which uses an operational amplifier OP2 sums up and integrates the voltages from said switches and a reference voltage Vs applied through a resistance R7 to obtain a set voltage Vr. An output signal is obtained from a filter circuit FC.