抄録
A method for measuring the frequency response of a plant with an arbitrary input has been developed (1). In this paper it is verified that this method is based on the correlation principle or the frequency response Gp (jω0) is measured as the ratio of complex variables of input-output cross-power spectrum φmc (jω0) to input power spectrum φmc (jω0).
Three types of circuits for the measurement are discussed with experimental results. “Servo type” circuit is simplest and has comparatively good characteristics. This type of circuit consists of one multiplier, one integrator, two resonance circuits, etc. “Analytical type” has the best characteristics but is in the most complicated structure. “Optimizing type” is most suitable for the measurement of a plant with a broad frequency band.
