Abstract :
This instrument is a final development of a previously described apparatus. It automatically plots and calibrates response curves within the audio spectrum of all manner of apparatus such as transmission lines, amplifiers, loudspeakers, networks and filters, etc. The response curves, together with their calibration raster, are displayed on the long afterglow screen of a cathode ray tube, and can be either viewed for about one minute or they can be photographed by means of a camera attachment. In Sections 1 to 3 the apparatus and its circuitry is described from the engineering angle, and Section 4 gives the mathematical analysis of various aspects of the circuits under operational conditions.
