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III. 3 Integrated systems. 
Elements and systems as described before can be combined, together with other systems, to 
compose integrated systems which perform a number of functions at the same operation. 
Also, the combination of functions serves to reduce errors and to keep error propagation 
under control. 
Examples are AN/USQ-28, IJzerman-Elliott. 
Their expected performance can be derived from the data of their component systems. No 
conclusive actual test values have been published so far. 
Their cost ranges from $ 500.000 to approx. $ 2.000.000 per integrated system . 
The author has his doubts as to whether it is economically justified to apply the degree of 
sophistication embodied in these systems. Whether it is possible to simplify the concepts 
and to reach the same goals with lower investment and operating cost is a question which 
should be decided in the near future.