312 GENERIC TYPES OF RADAR SYSTEMS AND TECHNIQUES 



Mixer 

 Inputs 



Mixer 

 Output 



Clutter 



jr 



Target 



Transmitter Signal 

 Clutter Signal 

 ^/Target Signal 



^0 fo+fd 



Filter 

 Output 



Filter ^ ^ 



Bandpass i^rget 



imin. 



(b) 



Fig. 6-14 Simple Stationary CW Doppler System: (a) Block Diagram, (b) Signal 

 Frequency Relations. 



Very often, the filter is not a single filter as shown in Fig. 6-14 but rather 

 a series of overlapping narrow band filters — each equipped with its own 

 detector — which covers the total desired doppler frequency band as shown 

 in Fig. 6-15. This permits very narrow bandwidth detection, measurement 

 of target velocity, and resolution between targets with different relative 

 velocities within the same antenna beamwidth. 



Filter 

 Outputs 



\ rn I \ ^^ A /^^ 1^ r^ 7"^ / 



' '' - \'' / "' V' 1'' / 



II; \l \ W f^\l \i >/ / ; 



'I' *' >/ \i ^\! *' V ' iw 



1 ^ l\ 





Fig. 6-15 Filter-Bank Detection Showing Contiguous Filters. 



