12-4] TYPES OF INPUT INFORMATION 619 



Combination Displays. In almost all radar systems the indicator 

 displays tactical and control information to the operator or pilot as well as 

 radar information. For example, in the operational AT radar systems the 

 indicator displays antenna position, IFF information, aircraft guidance 

 in the track mode, breakway time and aircraft attitude as well as the raw 

 radar data. Information coding of these signals given as circles, crosses, 

 and bars. 



With the advance of the concept of the contact analogue display (Para- 

 graph 12-10) and complex radar systems where computers are required 

 to sort out even raw radar data, additional dimension is given to the 

 symbolic logic by adding letters, numbers, and color to the method of data 

 presentation. Only special tubes, now in advanced stages of development, 

 are capable of presenting these new symbolic concepts. We shall discuss 

 color tubes, character type presentation tubes, and electroluminescence 

 displays in Paragraph 12-9. 



12-4 TYPES OF INPUT INFORMATION 



The preceding paragraphs have indicated many of the more important 

 types of inputs to radar displays. This paragraph will discuss these inputs 

 with the object of pointing out some of their salient characteristics which 

 can affect the display design problem. The primary purpose is to emphasize 

 the importance of obtaining a definition of display system inputs as a 

 prelude to system design. 



Three basic types of input signals are available from the radar and the 

 associated data processing system: 



1. Video signals 



2. Angle, range, and velocity reference signals 



3. Computed quantities 



In addition to the radar signals, the display may be required to handle 

 information from a number of other sources — e.g., aircraft instrument 

 signals, data link information, and equipment test and check-out signals. 



Radar Signals. The radar video signals and their associated range, 

 angle, and velocity reference signals together constitute an analogue 

 representation of the radar system's information matrix (see Paragraph 

 6-2). From the standpoint of the display device, the most important 

 properties of these input signals are: 



1. Number of matrix elements 



2. Number of matrix dimensions and the number of elements per 

 dimension 



