B&K Precision 4034 - Manual - Manual (Page 13)

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The illustrated network can be modified to provide different attenuation ratios by adding another resistor (less than
R1) between Z1 and the junction of R1 and R2.
When constructing such a device, the environment surrounding the components should also be designed to provide
smooth transition between the impedances. Acceptable performance can be obtained with discrete components using
short lead lengths; however, a full coaxial environment is preferred.
The characteristic impedance of a coaxial device is determined by the ratio between the outside diameter of the inner
conductor to the inside diameter of the outer conductor expressed as:
2.8.3 Rise Time Measurements in Linear Systems
Consider the rise time and fall time of associated equipment when measuring the rise time or fall
time of a linear device. If the rise time of the device under test is at least ten times slower than
the combined rise times of the instrument, the monitoring oscilloscope, and associated cables, the
error introduced will not exceed 1%, and usually may be ignored. If the rise time or fall time of
the test device is less than ten times slower than the combined rise times of the testing system,
determine the actual rise time of the device under test by using the following formula:
Rt equals the overall rise time or fall time of the entire measurement system and R1, R2, R3, etc.
are the rise times or fall times of the individual components in the system.
2.9 RS-232 Connection
The rear panel RS-232 connector is a standard DB-9 male connector configured as a DCE. The pin assignments
are defined in the table below:
Z
D
d
0
138
10
=
ε
log
Rt Rt Rt Rt
= + + +
( ) ( ) ( ) ......
1
2
2
2
3
2