A display part is provided with a display screen with a horizontal axis representing a time and a vertical axis representing an amount of modulation and a pre-emphasis waveform image is displayed on the display screen. In the pre-emphasis waveform image, a cursor can be arranged on a tap which corresponds to a portion in which a bit can be emphasized. An emphasis waveform addition part generates an emphasis waveform corresponding to the pre-emphasis waveform image on the display screen, based on an amount of amplitude changed according to movement of the cursor, and adds the emphasis waveform to the test signal. Thus, a user is allowed to make a setting with intuitive operation.