| 摘要 |
PROBLEM TO BE SOLVED: To calibrate a digital modulation wave in a short time by preliminarily matching a modulation wave level outputted from a digital modulating means with the modulation wave level outputted from an analog modulating means and then calibrating the digital modulation wave with the analog modulation wave as reference. SOLUTION: Appropriate attenuation quantity is set to an attenuator 11, and a modulation wave level from an analog modulator 3 side is recorded in a memory 21. A switching circuit 4 is switched over to a digital modulator 2 side, and the attenuation quantity set to the attenuator 11 is maintained as it is. Then, an attenuator 31 for digital modulation is adjusted from an attenuator control circuit 33 for digital modulation so that a modulation wave level outputted from a power detector 12 can coincide with an analog modulation wave level recorded in the memory 21, and the value is stored in the circuit 33. Thus, the output of the modulator 3 is made to coincide with that of the attenuator 31, and a digital modulation wave is calibrated with the analog modulation wave as reference. |
