R&S RT-Z1M User manual

R&S®RT‑Z1M
High-impedance buffer amplifier
Manual
1801314202
Version 05
(B1OZ2)

This manual describes the usage of the R&S RT-Z1M high-impedance buffer amplifier (1337.9200.02).
© 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.
Trade names are trademarks of the owners.
1801.3142.02 | Version 05 | R&S®RT‑Z1M
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol, e.g. R&S®RT-Z1M is indicated as
R&S RT-Z1M.

Contents
R&S®RT‑Z1M
3Manual 1801.3142.02 ─ 05
Contents
1 Safety information..................................................................................5
2 Product description............................................................................... 7
2.1 Key features and key characteristics..........................................................................7
2.2 Unpacking the product................................................................................................. 7
2.2.1 Inspecting the contents................................................................................................... 8
2.3 Description of the buffer amplifier.............................................................................. 8
2.3.1 Buffer amplifier box......................................................................................................... 9
2.3.2 Probe interface................................................................................................................9
2.3.3 Dimensions of buffer amplifier and probe......................................................................10
2.4 Accessories................................................................................................................. 10
2.4.1 Supplied accessories.................................................................................................... 10
2.4.2 Service accessories...................................................................................................... 10
3 Putting into operation..........................................................................11
3.1 Connecting the buffer amplifier to the oscilloscope............................................... 11
3.2 Identification of buffer amplifier and probe..............................................................12
3.3 Connecting the buffer amplifier to the DUT..............................................................12
3.4 Disconnecting the buffer amplifier from the DUT.................................................... 12
3.5 Using the buffer amplifier...........................................................................................13
3.5.1 Offset compensation..................................................................................................... 13
3.5.2 AC/DC switching........................................................................................................... 13
3.5.3 Analog bandwidth..........................................................................................................14
3.5.4 Self-alignment............................................................................................................... 14
3.5.5 R&S ProbeMeter........................................................................................................... 14
4 Typical characteristics.........................................................................15
4.1 Bandwidth....................................................................................................................15
4.2 Step response............................................................................................................. 15
5 Maintenance and service.....................................................................17
5.1 Cleaning....................................................................................................................... 17
5.2 Contacting customer support....................................................................................17
5.3 Returning for servicing...............................................................................................18

Contents
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5.4 Calibration interval......................................................................................................18
5.5 Storage and transport.................................................................................................18
5.6 Disposal....................................................................................................................... 18
6 Functional test......................................................................................20

Safety information
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5Manual 1801.3142.02 ─ 05
1 Safety information
The product documentation helps you use the product safely and efficiently. Follow the
instructions provided here and in the following chapters.
Intended use
The R&S RT‑Z1M high-impedance buffer amplifier 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 product is intended for the development, production and verification of electronic
components and devices in industrial, administrative, and laboratory environments.
Use the product only for its designated purpose. Observe the operating conditions and
performance limits stated in the data sheet.
The buffer amplifier is designed for usage with oscilloscopes that have a
Rohde & Schwarz probe interface. Supported Rohde & Schwarz oscilloscopes are lis-
ted in the product's data sheet.
Where do I find safety information?
Safety information is part of the product documentation. It warns you of potential dan-
gers and gives instructions on how to prevent personal injury or damage caused by
dangerous situations.
●Printed "Safety Instructions for Oscilloscopes and Accessories" in many languages
is delivered with your Rohde & Schwarz oscilloscope and probes.
●The documentation of the oscilloscope and measurement equipment provides
safety instructions when you need to take care during setup or operation.
Operating site
Only use the product indoors, and keep it dry. The product casing is not waterproof.
You can operate the product up to the altitude specified in the data sheet. The lowest
specified altitude for a product of the measurement setup defines the altitude for the
complete setup.
The product is suitable for pollution degree 2 environments where nonconductive con-
tamination can occur. For more information on environmental conditions such as ambi-
ent temperature and humidity, see the data sheet.
Electrical safety
Take the following measures for your safety:
●The buffer amplifier and the measurement instrument must be grounded. Ground-
ing is typically ensured through the grounding of the measurement instrument to
which the buffer amplifier is connected.
●Always connect the buffer amplifier to the oscilloscope first before connecting a
probe to the buffer amplifier and to the circuit under test.

Safety information
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●Do not apply voltages higher than the maximum rated voltage, see the imprint on
the buffer amplifier.
●When using the buffer amplifier in combination with a passive probe that can mea-
sure voltages higher than the maximum rated input voltage of the buffer amplifier
(e.g. R&S RT-ZP10): Observe the maximum rated voltage of the probe.
●Never open the casing of the buffer amplifier. If any part of the measurement equip-
ment is damaged or broken, stop using it.
Product integrity
The R&S RT‑Z1M can withstand a moderate amount of physical and electrical stress.
To avoid damage, treat the buffer amplifier with care:
●Do not exceed the specified voltage limits.
●Connect the R&S RT‑Z1M only to an instrument with Rohde & Schwarz probe
interface. Never connect it to a usual BNC jack. Although the 7 mm coaxial con-
nector looks like a standard BNC connector, it is constructed differently and does
not fit to the standard BNC jack. The interface of the R&S RT‑Z1M can withstand a
higher frequency limit.
●Prevent the buffer amplifier from receiving mechanical shock.
●Do not spill liquids on the buffer amplifier.
●Store the buffer amplifier in a shock-resistant case, e.g. in the foam-lined shipping
case.

Product description
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2 Product description
2.1 Key features and key characteristics
The R&S RT‑Z1M high-impedance buffer amplifier is an accessory for oscilloscopes
that have only inputs with 50 Ω input impedance. It allows you to connect measure-
ment equipment requiring a 1 MΩ load impedance to such oscilloscopes.
The R&S RT‑Z1M is equipped with the Rohde & Schwarz probe interface to be con-
nected to Rohde & Schwarz oscilloscopes that are compatible with this interface. How-
ever, oscilloscopes that already support a 1 MΩ input impedance do not support the
buffer amplifier.
The Rohde & Schwarz probe interface at the buffer amplifier input allows you to con-
nect various probes, e.g. passive probes, current probes, and active probes with
Rohde & Schwarz probe interface.
The R&S RT‑Z1M provides an integrated R&S ProbeMeter, which is used for probes
without an own R&S ProbeMeter. Usually, these probes are passive probes.
Table 2-1: Key features and key characteristics
Parameter R&S RT‑Z1M
Max. Bandwidth
Lowpass1:
Lowpass2:
DC - 500 MHz
DC - 200 MHz
DC - 20 MHz
Operating voltage window ±60 V (buffer amplifier alone)
Maximum input voltage 60 V DC
42 V AC Peak
Offset range Up to ±60 V depending on vertical scale
Input resistance 1 MΩ
Input capacitance 12 pF
AC coupling Cutoff frequency: 7 Hz
R&S ProbeMeter, dynamic range ±60 V
R&S ProbeMeter, measurement error < 0.1 %
R&S probe interface +5 V USB power; 0.5 A current limited
+12 high-power supply; 1 A current limited
2.2 Unpacking the product
The following items are included in the delivery:
●R&S RT‑Z1M high-impedance buffer amplifier
Unpacking the product

Product description
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●User manual of the R&S RT‑Z1M
●R&S RT-ZP10 10:1 passive probe
●User manual of the R&S RT-ZP10
●Accessories for R&S RT-ZP10 (delivery contents is listed in the user manual of the
probe)
●R&S RT‑Z1M data sheet
●"Basic Safety Instructions" brochure
●Calibration certificate
●Documented calibration values (if ordered)
2.2.1 Inspecting the contents
1. Unpack the product carefully.
2. Retain the original packing material. Use it when transporting or shipping the prod-
uct 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.
A description of the supplied probe accessories is listed in the user manual of R&S RT-
ZP10 passive probe.
2.3 Description of the buffer amplifier
Figure 2-1: R&S
RT ‑ Z1M high-impedance buffer amplifier with R&S RT-ZP10 passive probe
Description of the buffer amplifier

Product description
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1 = Buffer amplifier box
2 = R&S probe interface to connect an active probe to the buffer amplifier, and a contact ring to connect a
passive probe
3 = R&S probe interface to connect the buffer amplifier to an oscilloscope
4 = Release knob
5 = R&S RT-ZP10 passive probe
2.3.1 Buffer amplifier box
The buffer amplifier box contains active circuitry to attenuate, amplify or filter the
incoming signal and pass it to the 50 Ω input of the oscilloscope. There are no controls
or indicators on the buffer amplifier box.
2.3.2 Probe interface
The R&S RT‑Z1M is designed for connection to the Rohde & Schwarz probe interface
of the oscilloscope. The interface provides also a USB interface and supply voltages
(+5 V USB, +12 V high power). It transmits analog signals and digital data simultane-
ously.
The output of the R&S RT‑Z1M is connected to the oscilloscope. It consists of male
precision 7 mm (276 mil) coaxial connector and six pogo pins to ensure a thorough
connection.
Probes are connected to the input of the R&S RT‑Z1M. The Rohde & Schwarz probe
interface at the input provides the power supply and USB interface to recognize and
support active probes. It has also a contact ring to recognize a passive probe by its
readout pin. In any case, the probe is recognized automatically by the oscilloscope.
Figure 2-2: Output interface of the buffer amplifier
1 = Rohde & Schwarz probe interface with 7 mm (276 mil) coaxial connector and six pogo pins
2 = Release knob
Description of the buffer amplifier

Product description
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2.3.3 Dimensions of buffer amplifier and probe
The R&S RT‑Z1M high-impedance buffer amplifier and the R&S RT-ZP10 passive
probe have the following dimensions (all values in mm):
Figure 2-3: Dimensions of the R&S RT ‑ Z1M high-impedance buffer amplifier with R&S RT-ZP10
2.4 Accessories
2.4.1 Supplied accessories
Table 2-2 lists the accessories supplied with the R&S RT‑Z1M high-impedance buffer
amplifier. To order additional probes from Rohde & Schwarz, use the order number
provided in the table.
Table 2-2: Supplied accessories
Item Quantity Description Order number
R&S RT-ZP10 with probe accessories 1 10:1 passive probe 1409.7550.00
2.4.2 Service accessories
To order accessories for servicing the probe, contact your Rohde & Schwarz service
center. The following accessories are available:
Table 2-3: Service accessories
Item Description
R&S RT-ZK1 The service kit is used to calibrate the buffer amplifier, to
do performance tests, and for servicing. The service kit
includes all adapters and accessories to connect the buffer
amplifier to the required measuring instruments.
R&S RT‑Z1M Service Manual The service manual contains a detailed description of the
performance test to verify the specifications, and other
important service procedures.
Accessories

Putting into operation
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3 Putting into operation
Read and observe the instructions in Chapter 1, "Safety information", on page 5 before
using the buffer amplifier.
For your safety, follow the safety instructions delivered with your Rohde & Schwarz
oscilloscope and probe, and the instructions given in the manuals of your measure-
ment equipment.
Observe the voltage limits and ratings of the accessory and the measuring instrument.
Limits and ratings are marked on the products and listed in the data sheets.
The R&S RT‑Z1M works with oscilloscopes that have inputs with 50 Ω input impe-
dance only. Oscilloscopes that support a 1 MΩ input impedance do not support the buf-
fer amplifier.
During usage, the probe slightly heats up. Warming is normal behavior and not a sign
of malfunction.
3.1 Connecting the buffer amplifier to the oscilloscope
1. Make sure that the oscilloscope is properly grounded.
2. NOTICE! Risk of damaging the probe.
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.
Connect the buffer amplifier (1) to the Rohde & Schwarz probe interface of the
oscilloscope (2).
The buffer amplifier snaps in when connected properly to the port.
Figure 3-1: Connecting the R&S
RT ‑ Z1M to the Rohde & Schwarz oscilloscope
Connecting the buffer amplifier to the oscilloscope

Putting into operation
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► To disconnect the buffer amplifier:
a) Press and hold the release button (3).
b) Pull the buffer amplifier away from the oscilloscope.
3.2 Identification of buffer amplifier and probe
When the R&S RT‑Z1M is connected to the oscilloscope, the oscilloscope recognizes
the buffer amplifier and reads out the specific parameters from the data memory of the
buffer amplifier.
When a probe is connected to the buffer amplifier, the oscilloscope also reads the
probe-specific parameters through the buffer amplifier.
For information on probe-specific settings and information, refer to the oscilloscope's
user manual.
3.3 Connecting the buffer amplifier to the DUT
Observe the following step order when connecting the components of the measure-
ment setup. Also read and observe the instructions in Chapter 1, "Safety information",
on page 5.
1. Connect the buffer amplifier to the grounded oscilloscope.
2. Connect the probe to the buffer amplifier.
3. Switch off the test circuit.
4. Connect the probe to the DUT. Ensure a stable connection between the DUT and
the probe.
5. Switch on the test circuit.
3.4 Disconnecting the buffer amplifier from the DUT
Observe the following step order when disconnecting the measurement setup. Also
read and observe the instructions in Chapter 1, "Safety information", on page 5.
1. Switch off the test circuit.
2. Disconnect the probe from the DUT.
3. Disconnect the probe from the buffer amplifier.
4. Disconnect the buffer amplifier from the oscilloscope.
Disconnecting the buffer amplifier from the DUT

Putting into operation
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3.5 Using the buffer amplifier
All settings of the R&S RT‑Z1M are adjusted on the oscilloscope.
These settings are:
●Offset
●Input coupling
●Lowpass filter (bandwidth)
●Self-alignment
The gain or attenuation of the buffer amplifier is automatically set by the oscilloscope
depending on the vertical scale.
3.5.1 Offset compensation
The DC offset voltage is subtracted from the signal at the input of the R&S RT‑Z1M.
The offset is part of the vertical settings of the channel to which the buffer amplifier is
connected. For details, refer to the user manual of the oscilloscope.
Figure 3-2: Offset of R&S RT ‑ Z1M with R&S RT-ZP10, signal range 1V/Div
3.5.2 AC/DC switching
Without the buffer amplifier, the input coupling is limited to "DC" for a 50 Ω input impe-
dance. When the R&S RT‑Z1M high-impedance buffer amplifier is connected to the
channel input, AC coupling is also possible. Note that the R&S ProbeMeter does not
show the correct DC voltage on the probe tip if AC coupling is active.
The coupling is part of the vertical settings of the channel to which the buffer amplifier
is connected. For details, refer to the user manual of the oscilloscope.
Using the buffer amplifier

Putting into operation
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3.5.3 Analog bandwidth
The R&S RT‑Z1M features two lowpass filters of 200 MHz and 20 MHz. The filters
reduce bandwidth and thus noise during the measurement.
The bandwidth filter is part of the vertical settings of the channel to which the buffer
amplifier is connected. For details, refer to the user manual of the oscilloscope.
3.5.4 Self-alignment
The R&S RT‑Z1M has a self-alignment function. Self-alignment compensates mea-
surement errors caused by a termination impedance slightly different from 50 Ω, or an
ambient temperature different from the one at which the factory alignment was done.
When the buffer amplifier is detached from the oscilloscope, the values of the self-
alignment are discarded, and the original factory-alignment is reloaded. Thus, repeat
the self-alignment when you reattach the probe.
The self-alignment of the buffer amplifier is part of the probe settings of the channel to
which the buffer amplifier is connected. For details, refer to the user manual of the
oscilloscope.
3.5.5 R&S ProbeMeter
The R&S ProbeMeter is an integrated voltmeter that measures DC voltages with higher
precision compared to the oscilloscope's DC accuracy. The DC voltage is measured
continuously and runs parallel to the time domain measurement of the oscilloscope.
When the R&S ProbeMeter is active, the measured values are displayed on the oscillo-
scope. The R&S ProbeMeter state is part of the probe settings of the channel to which
the buffer amplifier is connected. For details, see the user manual of the oscilloscope.
Advantages of the R&S ProbeMeter:
●Measures DC voltages of different levels, no need to adjust the measurement
range of the oscilloscope.
●True DC measurement (integration time > 100 ms), not mathematical average of
displayed waveform.
●High measurement accuracy and low temperature sensitivity.
●Simple means of setting the oscilloscope's trigger level and vertical scaling if a
waveform is not visible.
●Independent of oscilloscope settings for position, vertical scale, horizontal scale,
and trigger.
With buffer amplifier, you can use the R&S ProbeMeter also with passive probes,
which do not have an own R&S ProbeMeter. In this combination, the R&S ProbeMeter
of the buffer amplifier takes effect. Note that the R&S ProbeMeter does not show the
correct DC voltage on the probe tip if AC coupling is active. Active probes that have a
R&S ProbeMeter use their own one as usual, the R&S ProbeMeter of the buffer ampli-
fier is not used.
Using the buffer amplifier

Typical characteristics
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4 Typical characteristics
The R&S RT‑Z1M high-impedance buffer amplifier has several gain or attenuation
modes. The mode of the buffer amplifier, and thus the gain or attenuation, depends on
the vertical scale and is set automatically by the oscilloscope to achieve optimized sys-
tem behavior.
4.1 Bandwidth
The R&S RT‑Z1M has a bandwidth of 500 MHz. You can reduce the bandwidth to 200
MHz or 20 MHz, see Chapter 3.5.3, "Analog bandwidth", on page 14. The transfer
functions of the gain or attenuation modes are shown in Figure 4-1.
The bandwidth of a system specifies the maximum frequency at which a purely sinus-
oidal signal is still transferred at 70 % (–3 dB) of its amplitude.
The bandwidth of the whole measurement setup also depends on the bandwidth of the
probe connected to the R&S RT‑Z1M, and the bandwidth of the oscilloscope.
Figure 4-1: Amplitude/frequency response of the R&S RT ‑ Z1M, all 7 modes
4.2 Step response
The step response up to 20 ns of the R&S RT‑Z1M high-impedance buffer amplifier is
shown in Figure 4-2. The propagation delay is normalized to the beginning of the step.
The amplitude is normalized to the steady state value.
Step response

Typical characteristics
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16Manual 1801.3142.02 ─ 05
Figure 4-2: Step response of the R&S RT ‑ Z1M (all 7 modes)
The rise time of a system is inversely proportional to the bandwidth. The following
approximation applies:
BW
trise
4.0

The minimum measurable rise time of the whole setup also depends on the bandwidth
of the probe connected to the R&S RT‑Z1M, and the bandwidth of the oscilloscope.
Step response

Maintenance and service
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5 Maintenance and service
Like all Rohde & Schwarz products, Rohde & Schwarz probes and adapters are of high
quality and require only minimum service and repair. However, if service or calibration
is needed, contact your Rohde & Schwarz service center. Return a defective product to
the Rohde & Schwarz service center for diagnosis and exchange.
5.1 Cleaning
1. Clean the outside of the product using a soft cloth moistened with either distilled
water or isopropyl alcohol. Keep in mind that the casing is not waterproof.
Note: Do not use cleaning agents. Solvents (thinners, acetone), acids and bases
can damage the labeling or plastic parts.
2. Dry the product completely before using it.
5.2 Contacting customer support
Technical support – where and when you need it
For quick, expert help with any Rohde & Schwarz product, contact our customer sup-
port center. A team of highly qualified engineers provides support and works with you
to find a solution to your query on any aspect of the operation, programming or applica-
tions of Rohde & Schwarz products.
Contact information
Contact our customer support center at www.rohde-schwarz.com/support, or follow this
QR code:
Figure 5-1: QR code to the Rohde
& Schwarz support page
Contacting customer support

Maintenance and service
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18Manual 1801.3142.02 ─ 05
5.3 Returning for servicing
Use the original packaging to return your R&S RT‑Z1M to your Rohde & Schwarzser-
vice center. A list of all service centers is available on:
www.services.rohde-schwarz.com
If you cannot use the original packaging, consider the following:
1. Use a sufficiently sized box.
2. Protect the product from damage and moisture (e.g. with bubble wrap).
3. Use some kind of protective material (e.g. crumpled newspaper) to stabilize the
product inside the box.
4. Seal the box with tape.
5. Address the package to your nearest Rohde & Schwarz service center.
5.4 Calibration interval
The recommended calibration interval for R&S RT‑Z1M high-impedance buffer ampli-
fier is two years. For servicing, send the probe to your nearest Rohde & Schwarz ser-
vice center (see Chapter 5.3, "Returning for servicing", on page 18).
5.5 Storage and transport
Protect the product against dust. Ensure that the environmental conditions, e.g. tem-
perature range and climatic load, meet the values specified in the data sheet.
Store the product in a shock-resistant case, e.g. in the shipping case.
Unless otherwise specified in the data sheet, the maximum transport altitude without
pressure compensation is 4500 m above sea level.
5.6 Disposal
Rohde & Schwarz is committed to making careful, ecologically sound use of natural
resources and minimizing the environmental footprint of our products. Help us by dis-
posing of waste in a way that causes minimum environmental impact.
Disposing of electrical and electronic equipment
A product that is labeled as follows cannot be disposed of in normal household waste
after it has come to the end of its life. Even disposal via the municipal collection points
for waste electrical and electronic equipment is not permitted.
Disposal

Maintenance and service
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19Manual 1801.3142.02 ─ 05
Figure 5-2: Labeling in line with EU directive WEEE
Rohde & Schwarz has developed a disposal concept for the eco-friendly disposal or
recycling of waste material. As a manufacturer, Rohde & Schwarz completely fulfills its
obligation to take back and dispose of electrical and electronic waste. Contact your
local service representative to dispose of the product.
Disposal

Functional test
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6 Functional test
The functional test confirms the basic operation of the R&S RT‑Z1M high-impedance
buffer amplifier and the R&S RT-ZP10 passive probe using simple measurement
equipment.
The functional test is not suitable to verify compliance with the specifications of the
R&S RT‑Z1M high-impedance buffer amplifier, because the test results are influenced
by the used oscilloscope.
Figure 6-1: Functional test
1. Connect the R&S RT‑Z1M to a Rohde & Schwarz oscilloscope as described in
Chapter 3.1, "Connecting the buffer amplifier to the oscilloscope", on page 11.
2. Connect the R&S RT-ZP10 probe to the probe interface of the buffer amplifier.
3. Connect the probe tip to the square wave output of the oscilloscope.
4. Connect the ground lead to the probe ground connector of the oscilloscope.
5. Press the [Preset] and then the [Autoset] key on the oscilloscope.
A square wave between 0 V and 1 V is displayed on the oscilloscope screen.