摘要:

The simple, automatic volume control circuit of radio receivers has been adapted for use in the studio amplifier of a broadcasting station to give a semiautomatic control of programs. The circuit adjustments for optimum control action were determined experimentally, and then this control action was analyzed by means of oscillograms. The effects of different time constants and degrees of control were noted, and methods for varying the latter indicated. The circuit is shown to be distortionless, except in so far as manual control of amplifier gain may be said to introduce "distortion". The control action, while not fully automatic, is complete enough to be of real assistance to the operator.

ISSN:1923-4287    

DOI:10.1139/cjr37a-011

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

A machine for plotting from air photographs, by the radial line method, has been developed by the Associate Research Committee on Surveys. The purpose of the plotter is to increase the accuracy and speed of extending minor control through strips of photographs by this method which is so widely used in Canada.A description of the machine is given, preceded by a brief explanation of the principles underlying its design.The methods so far employed in using the plotter are explained together with an examination of the sources of error arising in these methods, some of which are of general application to radial line plotting. Owing to the short time that the radial-stereoplotter has been in operation, conclusive statements cannot be made as to the results it will give when handled by an experienced operator, but already there is evidence of a considerable saving of time and gain in accuracy as compared with hand graphical methods of extending radial line control.

ISSN:1923-4287    

DOI:10.1139/cjr37a-012

出版商:NRC Research Press    

年代:1937

数据来源: NRC