THEORETICAL FUNDAMENTALS OF PULSE TRANSMISSION 7G5 



2 0.5 

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FREQUENCY 



»-^/:/4»T^Aj/4*n 



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Fig. 28 — Modification of impulses characteristic by slow cosine variation in 

 amplitude characteristic. 



echoes in very long lines resulting from impedance mismatches. Fine 

 structure deviations from a specified amplitude characteristic may in 

 principle be represented by a cosine Fourier series, since the amplitude 

 function is an even function of o). Thus, if the specified amplitude char- 

 acteristic is .4o(co), the actual amplitude characteristic ^(co) may be 

 represented by an infinite cosine Fourier series as: 



A(co) = .4o(ci;)[l + Oi cos COT + «? cos 2ajr + • • • + a^n cos mwT + • • •] . 



(8.01) 



