. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. TRANSMISSION OF INFORMATION 553 tude-frequency curve of the system. Similarly we add to the phase- frequency curve of the impressed wave, which is zero at all frequencies, the phase-frequency curve of the system and obtain for the received wave a phase-frequency curve identical with that of the system. The corresponding magnitude-time function gives the instantaneous value of the received current resulting from the impressed impulse. Thus we see that the steady state t
. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. TRANSMISSION OF INFORMATION 553 tude-frequency curve of the system. Similarly we add to the phase- frequency curve of the impressed wave, which is zero at all frequencies, the phase-frequency curve of the system and obtain for the received wave a phase-frequency curve identical with that of the system. The corresponding magnitude-time function gives the instantaneous value of the received current resulting from the impressed impulse. Thus we see that the steady state transfer admittance of a system is identical with the steady state description of the wave which is received over the system when it is subjected to an impulsive driving force. Once the form of this received wave is known the received wave resulting from any applied wave may be deduced by assuming the applied wave to consist of an infinite succession of impulses infinitesimally close together whose magnitudes vary with time in accordance with the given magnitude-time function. Methods for integrating the effect of this infinite succession of responses to impulses so as to obtain the transmitted wave have been developed. From this review it is evident that the so-called frequency distortion and transient distortion are merely two methods of describing the same changes in wave form which result from the storage of energy in parts of the transmission system. Significance of Product of Frequency-Range by Time Distortion of this sort with its accompanying intersymbol inter- ference may be unavoidable in the design of the system, or it may be deliberately introduced. The use of electrical filters to obtain multi-. C/2 >4ii Fig. 5 plex operation, as in carrier systems, is an example of its deliberate use. Consider the effect of introducing a low pass filter, as shown in Fig. 5, into an otherwise distortionless transmission system. If the imped- ances of the circuits to which the fil
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