Lmf

A plot of t and Zi is given in Fig. 6-4. It can be seen from the figure that there are two problems which were not considered in the ideal-line case. One is the termination problem, and the other the time-delay, or velocity, problem. It is important that the grid and plate networks be terminated so that there are no reflections; otherwise, as the frequency is varied, the reflected wave could alternately add to and subtract from the forward wave, thus producing variations in the amplifier gain as a function of frequency. From Fig. 6-4 it is apparent that the terminating impedance must vary with frequency in the manner indicated there, instead of being a simple resistor as depicted in Fig. 6-1.

The other problem, time delay, is serious from the standpoint of the transient response. The curve of Fig. 6-4 displays phase distortion; i.e., the time delay is not constant as would be the case with phase proportional to frequency. The discussion in Chap. 4 brought out the undesirable transient performance resulting from phase distortion.

Both of the problems which have been described above, termination and time delay, can be solved sufficiently well for practical purposes, although o |o

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