Sine wave generation circuit and test device

A sine wave generation circuit comprising:

• a first direct digital synthesizer configured to generate a digital sine wave fundamental signal having a frequency f0 in a normal operation mode and a calibration mode;
• a second direct digital synthesizer configured to generate a digital second harmonic correction signal having a frequency 2f0 in the normal operation mode;
• a correction circuit configured to superimpose the digital second harmonic correction signal on the digital sine wave fundamental signal;
• a Digital-to-Analog (D/A) converter configured to convert an output of the correction circuit into an analog sine wave signal;
• an output buffer configured to receive the analog sine wave signal and output an analog sine wave output signal;
• an Analog-to-Digital (A/D) converter configured to convert the analog sine wave output signal into a digital signal in the calibration mode;
• and
• a processing circuit configured to generate a spectrum by performing Fast Fourier Transform on the digital signal output by the A/D converter in the calibration mode and set a parameter of the second direct digital synthesizer based on information on the frequency 2f0 in the spectrum,
• wherein the first direct digital synthesizer and the second direct digital synthesizer include a same configuration and operate based on a common clock signal,
• wherein the first direct digital synthesizer includes:
• a first integrator configured to integrate a first input value according to the clock signal;
• and
• a first waveform generator configured to include a sine wave table and output a value of a sine wave according to an output of the first integrator by referring to the sine wave table, and
• wherein the second direct digital synthesizer includes:
• a second integrator configured to integrate a second input value according to the clock signal;
• and
• a second waveform generator configured to include a sine wave table and output a value of a sine wave according to an output of the second integrator.