DIRECT DIGITAL SYNTHESIZER, REFERENCE FREQUENCY GENERATION DEVICE, AND SINE WAVE OUTPUT METHOD

摘要

[Problem] To provide a DDS that achieves a more compact size and lower cost by not being provided with a ROM for storing a table or the like and by also minimizing the amount of computation. [Solution] A DDS (32) is provided with an NCO (24), a DAC (27), and a BPF (28). The NCO (24) outputs a sawtooth wave. The DAC (27) converts from a digital signal to an analog signal either the sawtooth wave outputted by the NCO (24) or a triangular wave signal converted by a waveform conversion circuit (26) on the basis of the sawtooth wave. The BPF (28), to which are inputted the signals converted to analog signals by the DAC (27), extracts a sine wave of a predetermined frequency by allowing passage of signals of a specific range of frequencies from among the inputted signals.