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TABLE 7–1
COMPARISON OF DIGITALSIGNALING METHODS
522
Type of Digital
Signaling
Minimum Transmission
Bandwidth Required a
(Where R Is the Bit Rate)
Error Performance
Baseband signaling
Unipolar
1
2 R (5–105) Qc B
a E b
N 0
b d
Polar
1
2 R (5–105) Qc B
2a E b
N 0
b d
Bipolar
1
2 R (5–105)
3
2 Qc B a E b
N 0
b d
Bandpass signaling Coherent detection Noncoherent detection
(7–24b)
(7–26b)
(7–28b)
OOK R (5–106) Qc a E b
1
b d (7–33)
2 e-(1/2)(E b /N 0 ) , a E b
b 7 1 (7–58)
4 B N 0
N 0
BPSK R (5–106) Qc 2a E b
b d (7–38) Requires coherent detection
B N 0
FSK 2∆F + R where 2∆F = f 2 - f 1
is the frequency shift
(5–89) Qc a E b
b d (7–47)
1
B
2 e-(1/2)(E b /N 0 ) (7–65)
N 0
DPSK R (5–106) Not used in practice
1
2 e-(E b /N 0 )
(7–67)
QPSK
1
2 R (5–106) Qc B
2a E b
N 0
b d (7–69) Requires coherent detection
MSK 1.5R (null bandwidth) (5–115) Qc 2a E b
b d (7–69)
1
B
2 e-(1/2)(E b /N 0 ) (7–65)
N 0 a Typical bandwidth specifications by ITU are larger than these minima [Jordan, 1985].