Abstract
The mechanism of the Cathode Ray Oscillograph is described and illustrated. The character of the cathode ray image (“spot”), produced when the ray impinges on the fluorescent screen, is briefly considered. Simple associated circuits are explained (including a “Time base” circuit). The advantages and disadvantages of the Cathode ray tube as a bio-electrical recording device are briefly examined.
Some of the problems associated with the design of a suitable amplifier are dealt with, in conjunction with the amount of amplification to be performed and the time relations of the electrical transient to be examined, taking the electrocardiogram as an illustration. A very short account of the theory of amplifier distortions is given, and a practical method of examining these by means of an “artificial patient” is described and demonstrated.