| 摘要 |
PURPOSE:To improve the accuracy of level detection by allowing the 1st and 2nd sub-level detectors to detect an output level of the 1st and 2nd common sections to switch the attenuation of the 1st and 2nd attenuator thereby preventing deterioration of the level detecting characteristic due to temperature. CONSTITUTION:The 1st and 2nd sub-level detectors 111, 112 detect an upper limit level point obtained for an excellent input/output linearity by using a detecting section. A controller 13 of the next stage receives an output signal of the 1st and 2nd sub-level detectors 111, 112, and when they detect that either or both reach the upper limit input level, the attenuation of the 1st and 2nd attenuators 121, 122 is switched at the same time. The attenuation is set to the 1st and 2nd linear region of the level detection section. |
