ISO BELL SYSTEM TECHNICAL JOURNAL 



The use of indicial response is not necessarily limited to any particular 

 coupler or method of response measurement, since frequency response and 

 indicial response are so closely related that one is a function of the other. 

 The choice of a closed coupler measurement does, however, permit some in- 

 terpretation of the results to be made by inspection, whereas other types of 

 measurement may require laborious mathematical means to obtain an in- 

 terpretation. Other types of vibration instrum.ents, such as recorders, 

 vibration pickups, crystal phonograph reproducers and carbon transmitters, 

 which sustain their response down to zero frequency, should lend themselves 

 to such methods of analysis. 



In conclusion, the writer wishes to acknowledge the assistance of Mr. T. J, 

 Pope in connection with the oscillographic work of this paper, and to express 

 his sincere appreciation. 



Bibliography 



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b. "i-lectric Circuit Theory and the Operational Calculus," McGraw-Hill. 



3a. Gilbert Swift, "Ampliher Testing by Means of Square Waves," Communications , 



Vol. 19, No. 2, Feb. 1939. 

 3b. Bedford and Frehendahle, "Transient Response of Multi-Stage Video Frequency 



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