Information Processing in the Time Domain 



347 



square waves and the combination of these square waves may be 

 set up with any desired hmits or sequence; we adjust them for 

 a given EKG signal. The hmits for this particular example are 

 320 to 66 milliseconds for a "fat" square wave and 88 to 2.7 

 milliseconds for a "thin" square wave. The trace designated 

 "recognition pulse'' in Figure 11 illustrates by the absence of a 

 pulse the rejection of an improper sequence and individual square 

 waves not falling within the defined acceptable limits. 



Figure 12 presents signature recognition as applied to the EKG. 

 Both high frequency artifact and baseline sway distort this signal 

 and are rejected, so that in this figure only three complexes have 

 been "recognized." Figure 13 is the identical EKG signal taken 

 at a slower paper speed to display more clearly the rejection of 

 sway artifact. 



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Major Period 



!rj^v4ru-i_irjr|i*i r|rv4j-t/ jrjrTff !rjri'-lrv-u-|rjj-lrun/-inr|ri^ — r^-^j^ r|n r-Y^ryy^^ 



Recogr.ltlon pjlse 



Fig. 13. Slow Writeout of Artifact Contaminated EKG. Rejection of those portions of 

 the record distorted by sway artifact is demonstrated by the absence of recog- 

 nition pulses in die lower trace. 



