Rohde & Schwarz RT-ZD40 User manual

R&S®RT-ZD40
Active Differential Probe
User Manual
1410536302
Version 06
(>:ÃÍ2)

This user manual describes the following R&S®RT-ZD models and options:
●R&S®RT-ZD40 (1410.5205.02)
© 2023 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: [phone] - 0
Email: [email protected]
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
All other trademarks are the properties of their respective owners.
1410.5363.02 | Version 06 | R&S®RT-ZD40
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol and without
product type numbers, e.g. R&S®RT-ZD40 is indicated as R&S RT-ZD40, and R&S®ProbeMeter is indica-
ted as R&S ProbeMeter.

Contents
R&S®RT-ZD40
3User Manual 1410.5363.02 ─ 06
Contents
1 Safety and regulatory information....................................... 5
1.1 Safety instructions................................................................................5
1.2 Labels on the product.......................................................................... 7
1.3 Warning messages in the documentation.......................................... 8
2 Product description...............................................................9
2.1 Key features and key characteristics..................................................9
2.1.1 Key characteristics..................................................................................9
2.1.2 Key features..........................................................................................10
2.2 Unpacking and checking....................................................................11
2.3 Description of the probe.....................................................................11
2.3.1 Probe head........................................................................................... 12
2.3.2 Probe box..............................................................................................13
2.4 Accessories and items....................................................................... 13
2.4.1 Accessories supplied............................................................................ 14
2.4.2 Optional accessories.............................................................................16
2.4.3 Service accessories.............................................................................. 17
3 Connecting the probe..........................................................19
3.1 Handling the probe............................................................................. 19
3.2 Connecting the probe to the oscilloscope....................................... 19
3.3 Identification of the probe..................................................................20
3.4 Connecting the probe to the DUT......................................................21
4 Features and characteristics of R&S RT‑ZD40 probes.... 26
4.1 Zero adjustment.................................................................................. 26
4.2 Micro button........................................................................................ 27

Contents
R&S®RT-ZD40
4User Manual 1410.5363.02 ─ 06
4.3 R&S ProbeMeter..................................................................................27
4.4 Offset compensation.......................................................................... 28
4.4.1 Differential offset................................................................................... 28
4.4.2 Common mode offset............................................................................29
4.5 Characteristics of differential probes............................................... 31
4.5.1 Common mode rejection ratio (CMRR).................................................32
4.5.2 Dynamic range and operating voltage window..................................... 33
4.5.3 Ground connection................................................................................34
4.6 Measurement principles.....................................................................34
4.6.1 Signal integrity of the transferred signal................................................36
4.6.2 Signal loading of the input signal.......................................................... 41
4.6.3 Probing philosophy............................................................................... 44
5 Maintenance and service.................................................... 46
5.1 Cleaning...............................................................................................46
5.2 Contacting customer support............................................................46
5.3 Returning for servicing...................................................................... 47
5.4 Calibration interval............................................................................. 47
5.5 Storage and transport........................................................................ 48
5.6 Disposal............................................................................................... 48
5.7 Spare parts.......................................................................................... 48
6 Functional check................................................................. 51

Safety and regulatory information
R&S®RT-ZD40
5User Manual 1410.5363.02 ─ 06
1 Safety and regulatory information
The product documentation helps you to use the product safely and efficiently.
Follow the instructions provided here and throughout the manual.
Intended use
The product is intended for the development, production and verification of elec-
tronic components and devices in industrial, administrative, and laboratory envi-
ronments. Use the product only for its designated purpose. Observe the operating
conditions and performance limits stated in the data sheet.
The R&S RT‑ZD40 differential probe is designed for measurements on circuits
that are only indirectly connected to the mains or not connected at all. It is not
rated for any measurement category.
The probe is designed for usage with oscilloscopes that have a Rohde & Schwarz
probe interface. Supported Rohde & Schwarz oscilloscopes are listed in the pro-
be's data sheet.
Where do I find safety information?
Safety information is part of the product documentation. It warns you of potential
dangers and gives instructions on how to prevent personal injury or damage
caused by dangerous situations. Safety information is provided as follows:
●In Chapter 1.1, "Safety instructions", on page 5. The same information is
provided in many languages as printed "Safety Instructions". The printed
"Safety Instructions" are delivered with the product.
●Throughout the documentation, safety instructions are provided when you
need to take care during setup or operation.
1.1 Safety instructions
Products from the Rohde & Schwarz group of companies are manufactured
according to the highest technical standards. To use the products safely, follow
the instructions provided here and in the product documentation. Keep the prod-
uct documentation nearby and offer it to other users.
Use the product only for its intended use and within its performance limits. Inten-
ded use and limits are described in the product documentation such as the data
Safety instructions

Safety and regulatory information
R&S®RT-ZD40
6User Manual 1410.5363.02 ─ 06
sheet, manuals and the printed "Safety Instructions for Oscilloscopes and Acces-
sories" document. If you are unsure about the appropriate use, contact
Rohde & Schwarz customer service.
Using the product requires specialists or specially trained personnel. These users
also need sound knowledge of at least one of the languages in which the user
interfaces and the product documentation are available.
Reconfigure or adjust the product only as described in the product documentation
or the data sheet. Any other modifications can affect safety and are not permitted.
Never open the casing of the product. Only service personnel authorized by
Rohde & Schwarz are allowed to repair the product. If any part of the product is
damaged or broken, stop using the product. Contact Rohde & Schwarz customer
service at https://www.rohde-schwarz.com/support.
In these safety instructions, the term "product" covers instruments (oscillo-
scopes), probes and their accessories.
Choosing the operating site
Only use the product indoors. The product casing is not waterproof. Water that
enters can electrically connect the casing with live parts, which can lead to elec-
tric shock, serious personal injury or death if you touch the casing. If
Rohde & Schwarz provides accessories designed for outdoor use of your product,
e.g. a protective cover, you can use the product outdoors.
Unless otherwise specified in the data sheet, you can operate the product up to
an altitude of 2000 m above sea level.
The product is suitable for pollution degree 2 environments where nonconductive
contamination can occur. For more information on environmental conditions such
as ambient temperature and humidity, see the data sheet.
Performing measurements
Take the following measures for your safety:
●To ascertain voltage-free state, use an appropriate voltage tester. Any mea-
surement setup including an oscilloscope is not suitable for this purpose.
●The maximum input voltage on channel inputs and the external trigger input
must not exceed the value specified in the data sheet.
●Observe all voltage and current ratings of the instrument, the probes, and the
accessories. Exceeding the allowed voltages can lead to an electric shock.
Limits and ratings are marked on the products and listed in the data sheets.
Safety instructions

Safety and regulatory information
R&S®RT-ZD40
7User Manual 1410.5363.02 ─ 06
Consider that the rated voltage depends on the frequency. The voltage limita-
tion curves or values are provided in the data sheet.
●Never cause any short circuits when measuring sources with high output cur-
rents.
●Use only probes and accessories that comply with the measurement category
(CAT) of your measurement task. If the product is rated for any measurement
category, the permitted category is indicated on the product and in the data
sheet. If you use other than Rohde & Schwarz accessories, make sure that
they are suitable for the instrument and the measurement task.
●Set the correct attenuation factor on the instrument according to the probe
being used. Otherwise, the measurement results do not reflect the actual volt-
age level, and you might misjudge the actual risk.
●The probe pins are extremely pointed and can easily penetrate clothes and
the skin. Handle the probe pins with great care. To exchange a probe pin, use
tweezers or pliers to avoid injuries. When transporting the accessories, always
use the box supplied with the probe.
●Prevent the probe from receiving mechanical shock. Avoid putting excessive
strain on the probe cable or exposing it to sharp bends. Touching a broken
cable during measurements can cause injuries.
●Set up all probe connections to the instrument before applying power.
1.2 Labels on the product
Labels on the casing inform about:
●Personal safety
●Product and environment safety
●Identification of the product
Table 1-1: Meaning of safety labels
Potential hazard
Read the product documentation to avoid personal injury or product damage.
Labels on the product

Safety and regulatory information
R&S®RT-ZD40
8User Manual 1410.5363.02 ─ 06
1.3 Warning messages in the documentation
A warning message points out a risk or danger that you need to be aware of. The
signal word indicates the severity of the safety hazard and how likely it will occur
if you do not follow the safety precautions.
WARNING
Potentially hazardous situation. Could result in death or serious injury if not avoi-
ded.
CAUTION
Potentially hazardous situation. Could result in minor or moderate injury if not
avoided.
NOTICE
Potential risks of damage. Could result in damage to the supported product or to
other property.
Warning messages in the documentation

Product description
R&S®RT-ZD40
9User Manual 1410.5363.02 ─ 06
2 Product description
2.1 Key features and key characteristics
The R&S RT‑ZD40 is a differential probe with high input impedance. It is used for
differential voltage measurements from DC to 4.5 GHz.
Differential probes can be used for single-ended and differential applications.
They are equipped with two high-impedance inputs and can measure the voltage
between any two test points. Unlike using single-ended probes, there is no need
to ensure that one of the test points is always at ground potential.
The comprehensive accessory set allows this probe to be connected to a wide
variety of devices under test (DUT). Provided with special features such as the
R&S ProbeMeter and the micro button, the R&S RT‑ZD40 is designed to meet
tomorrow's challenges in probing.
The probe is equipped with the Rohde & Schwarz probe interface. It can be con-
nected to any Rohde & Schwarz instrument that is compatible with this interface.
When connected to the front panel, the probe is controlled by the oscilloscope's
software. Supported oscilloscopes are listed in the data sheet.
Using a special adapter, the probe can also be connected to any other base unit
(see Chapter 2.4.2, "Optional accessories", on page 16).
2.1.1 Key characteristics
The key characteristics of the probe are the following:
Bandwidth DC to 4.5 GHz
Dynamic range
(differential input)
±5 V with ±5 V offset capability
10 V AC (Vpp)
Operating voltage window
(each pin to GND)
±8 V with ±22 V common mode offset capability
Available for R&S RT‑ZD40 probes with serial number
≥ 200000
Maximum non-destructive input voltage ±30 V
Between each signal pin and ground
Diff. input resistance 1 MΩ
Key features and key characteristics

Product description
R&S®RT-ZD40
10User Manual 1410.5363.02 ─ 06
Diff. input capacitance 0.4 pF
R&S ProbeMeter, measurement error <0.1 %
Extremely low zero and gain errors throughout the entire temperature range, no significant tem-
perature drift
Micro button
Rohde & Schwarz probe interface
2.1.2 Key features
Micro button
The micro button remotely controls important functions of the Rohde & Schwarz
oscilloscope. The function is assigned at the oscilloscope.
For details, see Chapter 4.2, "Micro button", on page 27.
R&S ProbeMeter
The R&S ProbeMeter measures the DC voltage of the input signal directly at the
probe tip. It provides a continuous high-precision DC voltage measurement that is
independent of the settings of the oscilloscope and runs in parallel to the time
domain measurement. If activated on the base unit, the measured value is dis-
played on the screen of the Rohde & Schwarz oscilloscope.
The R&S ProbeMeter simultaneously measures both differential and common
mode DC voltages.
For details, see Chapter 4.3, "R&S ProbeMeter", on page 27.
Data memory
The probe has an integrated data memory, containing the individual probe correc-
tion parameters (e.g. gain, delay, offset). These parameters are read out and pro-
cessed by the Rohde & Schwarz oscilloscope. As a result, the probe offers a high
degree of accuracy, and additional calibration procedures are not required.
Key features and key characteristics

Product description
R&S®RT-ZD40
11User Manual 1410.5363.02 ─ 06
2.2 Unpacking and checking
1. Unpack the product carefully.
2. Retain the original packing material. Use it when transporting or shipping the
product later.
3. Using the delivery notes, check the equipment for completeness.
4. Check the equipment for damage.
If the delivery is incomplete or equipment is damaged, contact
Rohde & Schwarz.
Delivery notes
The delivery contains the following items:
●R&S RT‑ZD40 differential probe
●Carrying case
●Accessory boxes
●User manual
●Data sheet
●Calibration certificate
●Documentation of calibration values (if
ordered)
●Safety instructions for oscilloscopes and
accessories (multilingual)
Accessories supplied with the probe are listed in Chapter 2.4.1, "Accessories
supplied", on page 14.
2.3 Description of the probe
The probe consists of the probe head for connection to the DUT, the probe box
for connection to the oscilloscope, and the probe cable.
Description of the probe

Product description
R&S®RT-ZD40
12User Manual 1410.5363.02 ─ 06
2.3.1 Probe head
The small and lightweight probe head is designed for easy handling and high-per-
formance measurements. The probe head is used for connecting the probe and
the DUT. Different accessories for the signal and ground sockets allow the probe
head to be connected to a wide range of DUTs.
(1) Positive signal socket
(2) Negative signal socket
(3) Ground socket
(4) Micro button
The accessories supplied for the probe head
sockets are listed in Chapter 2.4.1, "Accesso-
ries supplied", on page 14.
The ground socket is compatible with 0.64 mm
(25 mil) square pins and 0.6 mm to 0.8 mm
(24 mil to 35 mil) round pins.
Spacing of signal sockets: 4 mm (160 mil).
The signal sockets of R&S RT‑ZD40 have a special design to ensure optimal per-
formance. The signal sockets are not compatible to standard accessories based
on 0.64 mm (25 mil) square pins or 0.8 mm (35 mil) round pins. Use only special
accessories for R&S RT‑ZD40 provided by Rohde & Schwarz.
Description of the probe

Product description
R&S®RT-ZD40
13User Manual 1410.5363.02 ─ 06
2.3.2 Probe box
The probe box connects the probe and the oscilloscope via the Rohde & Schwarz
probe interface. The Rohde & Schwarz probe interface contains a male precision
7 mm (276 mil) BNC connector and six pogo pin connectors. This interface pro-
vides the required supply voltage and is also used to transmit analog signals and
digital data simultaneously. All the analog voltages required by the probe are gen-
erated in the probe box.
The BNC connector is a precision component designed to reach a much higher
frequency limit when connected to an instrument with Rohde & Schwarz probe
interface.
Connect the probe only to an instrument with Rohde & Schwarz probe interface.
Never connect it to a usual BNC jack, because this can damage the probe inter-
face.
(1) Rohde & Schwarz probe interface with
7 mm (276 mil) coaxial connector and 6 pogo
pins
(2) Release knob
2.4 Accessories and items
The figure below shows all accessories that are available for the R&S RT‑ZD40
differential probe.
Accessories and items

Product description
R&S®RT-ZD40
14User Manual 1410.5363.02 ─ 06
Figure 2-1: Available accessories
The R&S RT-ZA15 external attenuator is not a accessory of the R&S RT-ZD40.
Putting the R&S RT-ZA15 on the R&S RT-ZD40 can damage both parts mechani-
cally.
2.4.1 Accessories supplied
The following table shows the accessories supplied with the R&S RT‑ZD40 differ-
ential probe.
Accessories and items

Product description
R&S®RT-ZD40
15User Manual 1410.5363.02 ─ 06
Table 2-1: Accessories supplied
Item Quantity Description
100 Signal pin, solder-in
2Socket adapter, variable
spacing
2 Browser adapter, rigid
2Browser adapter, spring-
loaded
2 Lead, 6 cm / 2.4 in
1 Lead, 15 cm / 5.9 in
2 Mini clip
2 Micro clip
Accessories and items

Product description
R&S®RT-ZD40
16User Manual 1410.5363.02 ─ 06
Item Quantity Description
1 Marker band kit
1Carrying case with foam
inlay
For a list of spare parts, see Chapter 5.7, "Spare parts", on page 48.
2.4.2 Optional accessories
If the delivered accessories do not meet individual customer requirements,
Rohde & Schwarz offers different accessory sets for sale. The order numbers are
provided in the data sheet.
Table 2-2: Optional clips and leads
Accessories Items Quantity
R&S RT‑ZA4 mini clips Mini clip 10
R&S RT‑ZA5 micro clips Micro clip 4
R&S RT‑ZA6 lead set Lead, 6 cm / 2.4 in
Lead, 15 cm / 5.9 in
5
5
Table 2-3: Optional pins
Accessories Items Quantity
R&S RT‑ZA8 differential pin set Signal pin, solder-in
Socket adapter, variable spacing
Browser adapter, rigid
Browser adapter, spring-loaded
100
2
2
2
Accessories and items

Product description
R&S®RT-ZD40
17User Manual 1410.5363.02 ─ 06
Table 2-4: Optional adapters
Accessories Items Quantity
R&S RT‑ZA9 probe box to N / USB adapter
The adapter connects the R&S RT‑ZD40 differ-
ential probe to any other oscilloscope or any
other measurement instrument (e.g. a network
or spectrum analyzer).
Using the USB interface of the adapter, the
probe can be powered and controlled from any
conventional PC. However, full software func-
tionality is only provided by the supported oscil-
loscopes (see data sheet).
1
R&S RT‑ZA50 probe interface extender
The adapter is a breakout box that leads out the
R&S probe interface to the following standard
connectors: USB-C for power and control, SMA
for signal and DC jack for auxiliary supply.
Together with the R&S RT‑ZA51 probe to
3.5 mm adapter, it moves the R&S probe inter-
face closer to your test setup.
1
R&S RT‑ZA51 probe to 3.5 mm adapter
The probe adapter has an R&S probe interface
and standard connectors USB-C, 3.5 mm and
DC jack. Using this adapter, you can power and
control your Rohde & Schwarz probe without an
appropriate Rohde & Schwarz oscilloscope.
Together with the R&S RT‑ZA50 probe to
3.5 mm adapter, it moves the R&S probe inter-
face closer to your test setup.
1
2.4.3 Service accessories
To order accessories for servicing the probe, contact your Rohde & Schwarz ser-
vice center. The following accessories are available:
Accessories and items

Product description
R&S®RT-ZD40
18User Manual 1410.5363.02 ─ 06
Table 2-5: Service accessories
Item Description
R&S RT-ZK2 The service kit is used to calibrate the probe, to do perfor-
mance tests, and for servicing. The service kit includes all
adapters and accessories to connect the probe to the
required measuring instruments.
R&S RT‑ZD40 Service Manual The service manual contains a detailed description of the
performance test to verify the specifications, and other
important service procedures.
Accessories and items

Connecting the probe
R&S®RT-ZD40
19User Manual 1410.5363.02 ─ 06
3 Connecting the probe
3.1 Handling the probe
The R&S RT‑ZD40 can withstand a moderate amount of physical and electrical
stress. To avoid damage, treat the probe with care:
●Handle the probe by the probe head or probe box.
●Prevent the probe from receiving mechanical shock.
●Avoid strain on the probe cable and route it carefully.
●Do not spill liquids on the probe.
Preventing electrostatic discharge (ESD)
Electrostatic discharge is most likely to occur when you connect or disconnect a
DUT.
►NOTICE! Electrostatic discharge can damage the electronic components of
the product and the device under test (DUT).
Ground yourself to prevent electrostatic discharge damage:
a) Use a wrist strap and cord to connect yourself to ground.
b) Use a conductive floor mat and heel strap combination.
Discharge cables and probe clips before you connect them.
3.2 Connecting the probe to the oscilloscope
The probe is designed for usage with oscilloscopes that have a Rohde & Schwarz
probe interface. Supported Rohde & Schwarz oscilloscopes are listed in the pro-
be's data sheet.
►NOTICE! Risk of damaging the probe.
Connect the probe only to an instrument with Rohde & Schwarz probe inter-
face. Never connect it to a usual BNC jack, because this can damage the
probe interface.
Connecting the probe to the oscilloscope

Connecting the probe
R&S®RT-ZD40
20User Manual 1410.5363.02 ─ 06
Connect the probe box (1) to the Rohde & Schwarz probe interface of the
oscilloscope (2).
The probe snaps in when connected properly to the port.
Figure 3-1: Connecting the probe to the Rohde & Schwarz oscilloscope
► To disconnect the probe:
a) Press and hold the release button (3).
b) Pull the probe box away from the oscilloscope.
During usage, the probe slightly heats up. Warming is normal behavior and not a
sign of malfunction.
3.3 Identification of the probe
When the probe is connected to the oscilloscope, the oscilloscope recognizes the
probe and reads out the probe-specific parameters.
The oscilloscope settings for attenuation and offset are automatically adjusted.
After the probe is connected to the oscilloscope and the settings are adjusted, the
waveform is shown for the channel to which the probe is connected.
Identification of the probe