Range of values of k for transfer function

With the Laws criterion to solve, first of all, the characteristic equation: S^3 + 8S^2 + 15S + K = 0, for Laws form, in order to ensure the stability of the system, the characteristic root S must be in the left half-plane, in order to ensure that the Laws form the value of the first column of the full positive, which has the coefficients: 15-K/8 and K, according to the basis of the K0, so the range of K is: 0.

An open-loop system (eg, filter), the ratio of the output to the input as a function of frequency, that is, the frequency domain characteristics of the system. p>An open-loop system (e.g., filter) the ratio of output to input as a function of frequency, i.e., the frequency domain characteristics of the system. It is often expressed in terms of its amplitude-frequency characteristic and phase-frequency characteristic (function). The transfer function expresses the system's own characteristics independent of the input.

Extended information:

Assuming that the system has a single input, R(s), and a single output, C(s), and that the forward-channel transfer function, G1(s) G2(s), and the feedback (reverse channel) is negative feedback, H(s). ) is negative feedback H(s): then "artificially" disconnect the main feedback path of the system, multiply the forward channel transfer function with the feedback path transfer function, i.e., the open-loop transfer function of the system.

Then the open-loop transfer function is equivalent to B(s)/R(s), which is H(s)G1(s)G2(s), and the "disconnect" mentioned above refers to disconnecting the node where the feedback signal enters (the output of the feedback channel).

Baidu Encyclopedia - Open-loop Transfer Function