| 摘要 |
PURPOSE:To enable occurrence of distortion noise due to nonlinearity to be monitored by monitoring difference between a specified signal component which is generated at a region up to a lowest frequency of occupation band of a frequency multiplexed signal and each detection output level of the frequency multiplexed signal. CONSTITUTION:A frequency dividing multiplexed signal Si is fed to a band-pass filter 11 for enabling only a specified frequency component to be passed, amplified 12, and then detected 12 to obtain a detection output L1 of a specified frequency component. This output L1 indicates distortion noise level. On the other hand, a detection output L2 is obtained by detecting 14 the signal Si. Then, when outputs L1 and L2 are fed to a differential amplifier 15 to obtain a relative value of distortion noise which does not depend on the number of channels of the signal Si. Generation state of distortion noise due to nonlinearity can be monitored by setting this relative value to a distortion monitor output Sm. |
