The Bell System Technical Journal 1945 Vol 24

Excerpt from The Bell System Technical Journal, 1945, Vol. 24: A Journal Devoted to the Scientific and Engineering Aspects of Electrical Communication T has been known for a long time that all kinds of oscillators are subject to the trouble variously referred to as intermittent oscillation, motor boating, or squegging. In conventional circuits such as the Hartley the phenomenon is most likely to be observed if the grid leak and grid condenser are abnormally large. It is found that the time constant of this combina tion must be reduced as the frequency is raised and as the Q of the resonant circuit is decreased. At frequencies above a few hundred megacycles the problem of producing a practical circuit with suitable margin of stability is quite difficult. With the advent of the oscillator having automatic output control the problem assumed a new aspect}, 2 By application of an amplified control circuit a high degree of constancy of output together with low harmonic output is obtained. Satisfactory Operation is secured, however, only when suitable attention is given to\the characteristics of the control circuit. The intentional generation of pulses by means of intermittent oscillations of relatively high frequency has been studied to some extent, and circuits of this kind are employed in some television systems. Usually the high frequency oscillation is limited to a small portion of the low-frequency cycle, the charge stored during this period being allowed to dissipate itself relatively slowly during the remainder of the cycle. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.