PHASE MODULATOR

摘要

PURPOSE:To provide a modulator circuit whose circuit scale is reduced independently of whether or not its phase resolution is 2pi/(2's power). CONSTITUTION:Phase difference data between an input phase theta and a phase piin a half period are obtained by a subtractor 102 and absolute value data of the phase difference data are obtained from an absolute value circuit 103. A memory 104 stores data for a half period of a periodic function f(theta) and stored data are outputted from the memory by giving the absolute value data to the memory as a read address. A unity amplification factor amplifier 105 applies a multiple of -1 to data outputted from the memory and a unity amplification factor inverting amplifier 106 applies a multiple of -1 to data outputted from the memory and both data are given to a selector 107. The selector 107 is controlled by a carry from the subtractor 102 and selects either of the outputs of the amplifiers depending on the relation of quantity between the input phase thetaand a phase pi of a half period.