| 摘要 |
<p>PURPOSE:To easily, correctly and highly accurately regulate a prescribed level by automatically switching three attenuators for input level regulation. CONSTITUTION:In a case in which the input level, namely, the output level of a first attenuator 6 is at the specific level, and in the control range of the reference voltage of an A/D converter 8, in a case in which the output level of the first attenuator 6 is larger than the prescribed level and an integrating circuit 15 overflows, and in a case in which the output level of the first attenuator 6 is smaller than the prescribed level, and the integrating circuit 15 under- flows, three attenuators 5 to 7 at different attenuating quantities are automatically switched and used. Thus, the prescribed level can be easily, correctly and stably regulated.</p> |
