144 SAMPLED-DATA CONTROL SYSTEMS 
appeal but fails to be practical, partly because of the lack of basic work 
needed to develop the method. The last method, which appears at this 
time to hold the greatest promise of all, uses a physical sampler to sepa- 
rate the network from the plant. This structure permits the immediate 
use of the various conventional techniques without approximation and, 
in fact, it is shown that any physical pulse transfer function can be real- 
ized with a pulsed RC network of a particular form. This proof permits 
the designer who must use such networks for compensation to avail him- 
self of all the attractive time-domain synthesis procedures developed in 
the next chapter. 
