Intermodulation distortion measurement device and its measurement method

摘要

PPROBLEM TO BE SOLVED: To measure accurately intermodulation distortion X of a modulating signal a. PSOLUTION: In this intermodulation distortion measuring device, the intermodulation distortion of the modulating signal is measured by using a spectrum analyzer 30 for measuring a frequency spectrum 5 after performing level adjustment of the modulating signal a comprising a plurality of inputted carrier waves by a variable attenuator 26. An attenuation quantity setting table 32 for storing the attenuation quantity corresponding to each input level of the variable attenuator is provided so that the output level from the variable attenuator becomes a prescribed level, and all input signal levels of the modulating signal are calculated from measured frequency spectrums, and the attenuation quantities corresponding to all the calculated input signal levels are read out from an attenuation quantity table and set in the variable attenuator. The intermodulation distortion of the modulating signal is calculated from the frequency spectrum measured in the state. PCOPYRIGHT: (C)2005,JPO&NCIPI