Measurement of telegraph transmission

Various factors contribute to impair the quality of telegraph signals. For instance, there may be interfering currents either induced in the circuit or brought in by conduction, the proportioning of the circuit elements may be imperfect or batteries and relays may be out of adjustment. The result in any case is to distort the telegraph signals so that the received signals are not a true copy of those transmitted. The paper describes methods for measuring this distortion and for analyzing the results so as to indicate the nature and extent of the impairment and its probable cause.