Measuring Frequency Characteristics with the Photo-Audio Generator
W. Schaffer, G. Lubszynski · Proceedings of the IRE · 1931
A special alternating-current generator, a photo-audio generator, is used to good advantage as a source of current for measurements of variability with frequency. Compared with the known audio generators (tube generator with or without superposition) hitherto used for the same purpose, the photo-audio generator has the advantage of greater simplicity. The sources of error, as regards sine shape of its potentials and the variability with frequency are so small that they need not be considered in practical measurements. The described arrangement is so adjusted that the frequency range in question is continuous, and the result of the measurement is shown as a curve drawn by a recording instrument.