The envelopes of the power spectra of the PRBS, n sequence, and PRTS are shown in Fig. 3.11. All of the envelopes have [(sinx)/x]2 shape. The results shown in Fig. 3.11 are for signals with the same amplitude and the same value of Z. The envelopes for the n sequence and PRTS are higher than the

envelope for the PRBS because the even harmonics are zero in their spectra. This leaves more power to be distributed among the nonzero harmonics. The envelope for the PRTS signal is lower than for the n sequence because approximately one third of the inputs with a PRTS have a zero value, giving no contribution to the total signal power.