648 



DISPLAY SYSTEM DESIGN PROBLEMS 



the subjects were required to report the number of concentric circles that 

 were on a large display that subtended an angle of 14° at a viewing distance 

 of 12 ft. An experiment such as this is typical of the type of basic 

 investigations made for tactical display systems to determine the operator's 

 ability to report bearing and range information as a function of display and 

 system parameters. This kind of display problem would be involved in 

 CIC and AEW installations. The data reported were obtained at two levels 

 of brightness and two viewing distances. It appears that there is an 

 interaction between the number of circles, the size of the display, and the 

 illumination. It is also obvious that if the number of circles could be kept 

 below five, the effect of size and brightness can be minimized and the 

 reaction time will be a negligible factor as a human engineering problem. 

 An important characteristic of the human operator is his ability to receive 

 and act upon information. This characteristic is predicated on the fact that 

 all the characteristics of the signal are well above the threshold of the 

 observer and he has merely to extract the information from the symbol and 

 act upon it. In this class of behavior, the operator is acting as a digital 

 device in that he absorbs information and acts upon it in serial fashion. 

 There is a separate response to each signal even though the signals may be 

 in sequence. This last statement is to differentiate this form of activity 

 from that which exists when the operator is acting as an error detector in a 

 tracking system. This case will be considered in a subsequent paragraph. 



1 23456789 10 

 INFORMATION PRESENTED (H,in bits/sec) 



Fig. 12-31 Information Transmitted as a Function of Speed of" Presentation and 

 Mode of Response. 



