Digital Signal Processing Reference
In-Depth Information
TDR
TDT
V
x
R
t
d
,
1
t
d
, 2
Gain=1
[VCVS]
+ −
Driving line
Z
0
Z
0
R
Ix
0.5 V
D
S
D
t
d,
gap1
t
d
, gap
2
t
d
, gap
1
[CCCS]
[CCCS]
Slot
Z
gap
+
Z
gap
+
Z
gap
V
x
I
x
V
y
I
y
−
−
Gain = 1
Gain = 1
Far-end
crosstalk
Near- end
crosstalk
V
y
Victim line
t
d,
3
Gain = 1
[VCVS]
t
d,
4
+ −
R
Z
0
Z
0
R
I
y
Figure 10-13
Equivalent circuit of two transmission lines crossing over a slot in the
reference plane.
0.06
0.04
0.02
0.00
−
0.02
−
0.04
−
0.06
0.7
0.8
0.9
0.1
1.1
1.2
1.3
1.4
1.5
Time, ns
Figure 10-14
Crosstalk coupled via a slotline transmission line on a victim line 1.0 in.
away.
launched on the sourcing line (250 mV). If multiple lines are crossing a gap in
the reference plane, a significant amount of noise would be coupled onto the bus,
which can destroy signal integrity.
Differential
Differential signaling is much more immune to the harmful effects
of nonideal return paths because the adjacent transmission line provides a rela-
tively low-impedance path for the current to return. From a mathematical point of
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