Information Processing in the Time Domain 



335 



fast frequency of approximately thirty-six cycles per second. Again 

 we see the primary square wave, or major period, reflecting the 

 "dominant rhythin" and the second derivative scjuare wave or 

 minor period rather clearly reflecting the fast component. If these 

 three trains of square waves are smoothed individually by an 

 integration filtering operation, inixecl, and smoothed once more, 

 the reconstituted analog signal may be written out as shown on 

 the bottom trace. In a way, this reconstitution is an inversion of 

 the operations which generated the square waves in the first place. 

 There is a rather striking resemblance between the reconstituted 

 primary and the original signal, although careful inspection will 

 reveal some discrepancies in both phase and amplitude. However, 

 the wave shape, by and large, has been retained. If the process 



PERIOD RECONSTITUTION 

 ELECTROENCEPHALOGRAM 



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Fig. 4. Left Parieto-Occipital EEC. Period analysis of the electroencephalogram 

 yields the three square wave trains shown. The three square wave trains are 

 smoothed, mixed and smoothed to reconstitute the wave forms in the bottom 

 trace. The complex EEG signal retains enough information in the processing 

 to allow clinical interpretation. 



