Agilent Technologies N1021B User manual

Agilent N1021B
Differential TDR Probe
User’s Guide

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N1021B
User’s Guide
Agilent N1021B—At a Glance 2
Proper Handling Techniques 5
Adjusting the Probe Tip Separation 7
Attaching to a Positioner 8
Calibrating the Probe 9
Performing an Operation Verification 11
Probing a Differential Trace’s Length
Midpoint 15
Probe Characteristics 16
Returning the Probe for Service 17
Safety Symbols 18

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Agilent N1021B—At a Glance
The N1021B facilitates differential time domain
reflectometry measurements in situations where RF
connectors are unavailable. It is ideal for use with the
Agilent 54754A TDR plug-in module. Although the
N1021B probe was designed for TDR applications, it
is also suitable as a high bandwidth, passive probe
for non-TDR applications.

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Using the Probe
■Refer to “Proper Handling Techniques” on page 5
before using the probe for the first time.
■Refer to “Calibrating the Probe” on page 9 to cali-
brate the test setup for use with the probe.
CAUTION Electrostatic discharge (ESD) can damage or destroy
electronic components and the input circuits on plug-
in modules. Coaxial cables with both ends
unconnected may store electrostatic charges. Before
connecting any coaxial cable to a device or
instrument, momentarily short the center and outer
conductors of the cable. When making connections,
ensure the proper use of a grounded, resistor-isolated
wrist strap.
CAUTION Before connecting the phase-matched cables, always
discharge any static buildup. Momentarily short the
center and outer conductors of the cable together.
Avoid touching the front-panel input connectors
without first touching the frame of the instrument.

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Supplied Accessories
Table 1 lists the items provided with the probe. The
information on the actual shipping list is more accu-
rate and should supersede the information in this
list. To order the parts listed in the table, search for
“Parts” at www.agilent.com/Find/Parts. There are no
replaceable parts on the probe.
Table 1. Items Supplied With N1021B
Item Qty Part Number
Pair of phase-matched cables
(1m)
1 N1021-60003
SMA 50ΩLoad (m) 2 1810-0118
SMA Short (m) 2 0960-0055
SMA Adapter (f-f) 2 1250-1666
Positioner Adapter 1 N1021-60008
M2.5 socket-head screws (6 mm
long)
2—
M2.5 Allen wrench 1 —
ESD Wrist Strap 1 9300-1367
ESD Wrist Strap Ground Cord 1 9300-0980

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Proper Handling Techniques
Use the following techniques to avoid damaging the
probe. The probe tips are not replaceable.
■Hold the probe perpendicular to the device under
test. Probing angles greater than 15°from perpen-
dicular will likely damage the tips over time.
■Do not apply side force to the probe tips.
■Avoid fully compressing the probe-tip springs.
■Hand tighten the cable connection to the probe. Or,

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use a 5 in-lb (0.56 Nm) torque wrench.
■Before cleaning the external case parts of the
N1021B, disconnect the probe from all cables. Use
a dry cloth or one slightly dampened with a mild
soap and water solution. Do not attempt to clean
internally.
CAUTION Applying excessive force when handling the probe can
result in bent or otherwise damaged probe tips. Apply
only enough pressure to ensure a secure connection.
The probe tips are spring loaded. Avoid fully
compressing the probe-tip springs. The probe tips are
not replaceable.
CAUTION Do not use too much liquid in cleaning the probe.
Water can enter the case.

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Adjusting the Probe Tip Separation
Turn the probe spacing adjustment wheel to change
the spacing between the probe tips. Avoid using
excessive force at the limits of the adjustment range.

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Attaching to a Positioner
The supplied adapter allows you to attach the probe
to the N1020A TDR Probe positioner, as well as many
robotic arms and common industry positioners. Two
M2.5 socket-head screws (6 mm long) and an Allen
wrench are provided to attach the adapter to the
N1021B. The two screw holes on the probe are sepa-
rated by ¼-inch (6.4 mm) on center. Torque each
screw to 5 in-lb (0.56 Nm). A ¼-inch hole in the
adapter is used to attach the adapter to the posi-
tioner.