On the design of A-C networks for servo compensation

This paper presents an analytical method for analysis and synthesis of networks for AC servo compensation. The response of a linear network to a modulated suppressed-carrier excitation is formulated in terms of in-phase and quadrature carrier components. The relationship between the modulation on these components and the exciting modulation is shown to depend upon operators simply related to the original network function. The expansion of the data-frequency operators into partial fractions is shown to lead to a simple synthesis procedure for deriving the original network operator from the in-phase or quadrature operators. As an example, the process is applied to the derivation of a representative network for lead compensation of an AC servo responsive to the in-phase component of error signal. The use of RC networks in AC servo compensation is shown to be limited to derivative types of equalization.