| 摘要 |
PURPOSE:To discriminate the discrimination of stable/instable state in a very short time, by means of the operation using analog circuits. CONSTITUTION:A sinusoidal wave signal having a prescribed amplitude (a) the frequency of which is changed logarithmically is inputted to an automatic control system X being objective of the discrimination of stable/instable state with a sinusoidal wave generator 1 continuously. Then, the amplitude (b) of an output signal of a feedback loop element H(S) of the system X is detected at an amplitude detector 2 and the common logarithm of the amplitude (b) is obtained by an amplitude logarithm circuit 3. A differentiation operating circuit 4 obtains the absolute value of the difference (c) between the amplitudes (b) and (a), and the common logarithm of the difference c is obtained with a differential logarithm circuit 6. A gain versus frequency characteristic circuit 7 substracts log10 c from log10b, the difference is multiplied by 20 to obtain the dB value G(S) of the gain versus frequency characteristics of an open loop transfer function of the X. Thus, the stability and instability of the control system X is discriminated easily, by using the value G(S). |
