HP 54753A User Manual

Transmission Line Theory Applied to Digital Systems
Transmission Line Design
11-12
(8)
Solving equation 8, V
1
= 0.58 V. The implication of this result is that stubbing
off the line with gate loads in a distributed fashion is not recommended, due to
the reduced initial voltage swing. However, it would be acceptable to lump the
loads at the end of the line.
Since the value of the load resistor is greater than the characteristic impedance,
the voltage swing at the load resistor is greater than v1 by the amount of ρ
L
V
1
,
(in this example, 193 mV). When t = T
D
+ T
1
, the voltage at B is equal to 0.387
V; so 82 mV of undershoot occurs. Undershoot on the falling edge is defined as
the amount of voltage step above the nominal logic 0 level of 0.305 V. Overshoot
in the low logic state is defined as the amount of voltage change below the logic
0 level.
Figure 11-6
Voltage Waveforms for Points A and B in Example 2
In Figure 11-6, the voltage waveforms at points A and B of this example are
shown as a function of time. To be more realistic, the waveform in the figure is
shown to be a negative-going ramp rather than an abrupt step function. The
V
1
I
dc
–
()
Z
o
=

HP 54753A Specifications

General

Brand	HP
Model	54753A
Category	Control Unit
Language	English