CHAPTER 

 XIV 



INFORMATION PROCESSING IN THE 

 TIME DOMAIN 



Neil R. Burch, M.D. and Harold E. Childers 



T« 



HIS paper briefly outlines the work we are conducting in 

 the Department of Psychiatry, Baylor University College of Medi- 

 cine, and in the laboratories of the Houston State Psychiatric 

 Institute. The basis for this research is the theory that a special 

 case of analysis in the time domain has something to offer both in 

 time resolution and in economy of information processing that 

 cannot be readily obtained from frequency analysis or from more 

 conventional time sampling procedures. The analytical process to 

 be described we have called period analysis (1). 



Given an amplitude function distributed in tiine, there are a 

 limited number of questions that may be asked of the function 

 to yield an analysis or to undertake data reduction. Consider the 

 following four cases: 1) One inay focus on the amplitude and ask 

 the question "how much" over a time, T; one may focus on both 

 time and amplitude and ask the question "how much" at par- 

 ticular points in time, either 2) points at fixed intervals or 3) points 

 related to an event; finally, 4) one may focus on selected events 

 and ask the question "when." 



A theorem in information theory tells us that if we take this 

 amplitude distribution in time and sample it every so often, we 

 will retain complete information about the signal. Presented more 

 formally, the theorem reads, "If a function G{t) contains no fre- 

 quencies higher than W cycles per second, it is completely deter- 

 mined by giving its ordinatcs at a series of points spaced jrr 

 seconds apart, the series extending throughout the time domain" 

 (2) (Case 2). A corresponding theorem for sampling in the frc- 



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