The Electronic Complex Plane Scanner

The electronic complex plane scanner is an electronic analog computer which scans the complex plane electrically by running a point along the imaginary axis. By so doing, the magnitude of a system function represented by its poles and zeros is obtained. This is accomplished by multiplying ac voltages representing the distances from the poles to the running point, multiplying the distances from the zeros to the running point, and then dividing the latter product by the former product. This process is mechanized by means of logarithmic networks. By adding a real perturbation to the path of the running point, a perturbation of the magnitude of the system function results. The latter perturbation is shown to be proportional to the phase slope. The computing process is done at a high speed so that it is possible to devise various types of oscillographic displays. One form in which both magnitude and phase slope are simultaneously displayed as a function of frequency is described in this paper.