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Baseband Pulse and Digital Signaling Chap. 3
Unipolar NRZ
Binary waveform in
w 1 (t)
R bits/s
bit
digital-to-analog
converter
Multilevel polar NRZ
L-level waveform out
w 2 (t)
D symbols/s = R/
and R bits/s
(a) Bit Digital-to-Analog Converter
w 1 (t)
0
T b
t
(b) Input Binary Waveform, w 1 (t)
T s
w 2 (t)
7
6
5
4
3
2
1
T s
–1
t
–2
–3
–4
–5
–6
–7
(c) L = 8 = 2 3 Level Polar NRZ Waveform Out
Figure 3–22 Binary-to-multilevel polar NRZ signal conversion.
The relationship between the output baud rate D and the associated bit rate R is identical
to that discussed in conjunction with the dimensionality theorem in Sec. 3–4, where it was
found that the bandwidth was constrained by B D2.
The PSD for the multilevel polar NRZ waveform (Fig. 3–22c) can be obtained by
the use of Eq. (3–36a). Evaluating R(k) for the case of equally likely levels a n , as shown in
Table 3–5, we have, for the case of k = 0,