Digital Signal Processing Reference
In-Depth Information
Tx Pull-Down
200
0)
(0.357 V, 28.6 mA)
Tx (
t
<
2
t
d
)
(1.4mA,2.517V)
Tx (
t
=
100
R
x
0
T-line
0)
(2.357 V,
−
11.4 mA)
Tx (
t
=
t
d
)
(2.757 V,
−
3.4 mA)
Rx (
t
=
−
100
−
200
Tx Pull-Up
−
300
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Voltage [V]
(c)
20
2
t
d
)
(2.517 V,1.4 mA)
Tx (
t
=
R
x
10
0
−
10
T-line
t
d
)
(2.757 V,
−
3.4 mA)
Rx (
t
=
−
20
Tx (
t
=
0)
(2.357 V,
−
11.4 mA)
−
30
Tx Pull-Up
−
40
−
50
2.0
2.2
2.4
2.6
2.8
3.0
Voltage [V]
(d)
Figure 11-20
(
Continued
)
at this point that they are difficult to discern, so Figure 11-20d shows a close-up
view of the diagram.
The process of drawing load lines continues until the changes in voltage and
current become small enough to suit our need. We can then construct voltage and
current waveforms by reading the values from the Bergeron diagram. We must
keep in mind that points that occur at intersections with the transmitter load line
contribute to the transmitter waveform, and points that occur at intersections with
receiver load line contribute to the waveform at the receiver. The full Bergeron
diagram is shown in Figure 11-21 along with the voltage and current waveforms.
At this point we note that we generated the voltage and current numbers shown
in the waveforms by repetitively solving simultaneous Ohm's law equations
subject to initial voltages and currents—the analytical equivalent of the Bergeron
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