| 摘要 |
PURPOSE:To detect easily the open loop gain of a feedback system by applying the disturbance to the feedback system and having comparison between the phase of the sum of optional two of the signals set before and after the adding point of disturbance and the disturbance signal and the phase of the remaining signal. CONSTITUTION:The output of an amplifier 1 to be measured is sent back to an input via a disturbance adder 3 through a feedback system. An oscillator 4 applies the disturbance signal of a specific frequency to the input of the adder 3 of the feedback system. The sum of optional two (input/output signals of the adder 3) among those three, i.e., the disturbance signal and the input and output signals of the adder 3 is obtained by a signal adder 5. Then the difference of phase between those two signals and the remaining one (disturbance signal) is applied to a phase comparator 2. Thus the output of a gain detector is obtained. |
