R&S RT-ZS60 User Manual

R&S

®

RT-ZS60
Active Voltage Probe

User Manual

User Manual

Version 04

1418734202

(>B×Z2)

This user manual describes the following R&S®RT-ZS models and options:

●

R&S®RT-ZS60 (1418.7307.02)

© 2019 Rohde & Schwarz GmbH & Co. KG

Mühldorfstr. 15, 81671 München, Germany

Phone: [phone] - 0

Fax: [phone]

Email: [e-mail]

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.

1418.7342.02 | Version 04 | R&S®RT-ZS60

Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol and without
product type numbers, e.g. R&S®RT-ZS60 is indicated as R&S RT-ZS60.

1171.1307.42 - 05

1

Safety Instructions
Instrucciones de seguridad

Risk of injury and instrument damage

The instrument must be used in an appropriate manner to prevent
personal injury or instrument damage.

● Do not open the instrument casing.

● Read and observe the "Basic Safety Instructions" delivered as

printed brochure with the instrument.

● Read and observe the safety instructions in the following sections.

Note that the data sheet may specify additional operating conditions.

● Keep the "Basic Safety Instructions" and the product documentation

in a safe place and pass them on to the subsequent users.

Riesgo de lesiones y daños en el instrumento

El instrumento se debe usar de manera adecuada para prevenir
descargas eléctricas, incendios, lesiones o daños materiales.

● No abrir la carcasa del instrumento.

● Lea y cumpla las "Instrucciones de seguridad elementales"

suministradas con el instrumento como folleto impreso.

● Lea y cumpla las instrucciones de seguridad incluidas en las

siguientes secciones. Se debe tener en cuenta que las
especificaciones técnicas pueden contener condiciones adicionales
para su uso.

● Guarde bien las instrucciones de seguridad elementales, así como

la documentación del producto, y entréguelas a usuarios
posteriores.

Safety Instructions - Informaciones de seguridad

1171.3200.12 E/Esp-1 Page 1

Safety Instructions for Active Voltage Probes

When handling active voltage probes, the following basic rules must be observed.
Prior to using an active voltage probe, read the applicable manual including the safety
instructions. Keep the safety instructions and the product documentation in a safe place
and pass them on to other users. Use active voltage probes exclusively within the
measurement ranges specified in the applicable data sheets. Rohde & Schwarz accepts
no responsibility for misuse of the product. Use only the accessories supplied with the
active voltage probe.

Risk of electric shock

Do not connect an active voltage probe to any voltage that exceeds the maximum
permissible input voltage specified in the data sheet. Non-compliance with this
instruction carries the risk of an electric shock.

Make sure not to cause any short circuits when performing measurements on sources
with high output currents. Short circuits may cause injuries or burns.

Risk of injury caused by pointed object

The pins of the active voltage probes are extremely pointed and can easily penetrate
clothes and the skin.

Therefore, handle the probe pins with great care. When transporting an active voltage
probe, e.g. when carrying it in a pocket or tool bag, always use the box supplied with
the probe. To exchange a probe pin, use tweezers or pliers to avoid injuries.

Instructions - Instrucciones

1171.0300.62 E/Esp-3

Instructions for Electrostatic Discharge Protection

Risk of damaging electronic components

To avoid damage of electronic components, the operational site must be
protected against electrostatic discharge (ESD).

Wrist strap with cord

Ground connection

of operational site

Heel strap

Floor mat

The following two methods of ESD protection may be used together or
separately:

, Wrist strap with cord to ground connection

, Conductive floor mat and heel strap combination

1171.0200.22-06.00

Customer Support

Technical support – where and when you need it

For quick, expert help with any Rohde & Schwarz equipment, contact one of our Customer Support
Centers. A team of highly qualified engineers provides telephone support and will work with you to find a
solution to your query on any aspect of the operation, programming or applications of Rohde & Schwarz
equipment.

Up-to-date information and upgrades

To keep your instrument up-to-date and to be informed about new application notes related to your
instrument, please send an e-mail to the Customer Support Center stating your instrument and your wish.
We will take care that you will get the right information.

Europe, Africa, Middle East

Phone [phone]

[e-mail]

North America

Phone 1-888-TEST-RSA (1-888-837-8772)

[e-mail]

Latin America

Phone [phone]

[e-mail]

Asia/Pacific

Phone [phone]

[e-mail]

China

Phone [phone] /

[phone]

[e-mail]

Contents

R&S®RT-ZS60

3User Manual 1418.7342.02 ─ 04

Contents

1 Product Description.............................................................. 5

1.1 Key Features and Key Characteristics............................................... 5

1.1.1 Key Characteristics................................................................................. 5

1.1.2 Key Features...........................................................................................6

1.2 Unpacking..............................................................................................7

1.2.1 Inspecting the Contents.......................................................................... 7

1.3 Description of the Probe...................................................................... 8

1.3.1 Probe Head.............................................................................................8

1.3.2 Probe Box............................................................................................... 9

1.4 Accessories and Items......................................................................... 9

1.4.1 Accessories Supplied............................................................................10

1.4.2 Optional Accessories............................................................................ 12

1.4.3 Service Accessories..............................................................................13

2 Putting into Operation.........................................................14

2.1 Connecting the Probe to the Oscilloscope...................................... 15

2.2 Identification of the Probe..................................................................16

2.3 Using the Probe.................................................................................. 16

2.3.1 Zero Adjustment....................................................................................16

2.3.2 Micro Button..........................................................................................17

2.3.3 Offset Compensation............................................................................ 17

2.3.4 R&S ProbeMeter...................................................................................18

3 Connecting the Probe to the DUT...................................... 20

4 Measurement Principles..................................................... 25

4.1 Signal Integrity of the Transferred Signal.........................................27

Contents

R&S®RT-ZS60

4User Manual 1418.7342.02 ─ 04

4.1.1 Bandwidth............................................................................................. 27

4.1.2 Connection Inductance......................................................................... 29

4.1.3 Performance with Different Connection Types......................................30

4.2 Signal Loading of the Input Signal....................................................32

4.2.1 Input Impedance................................................................................... 32

4.3 Probing Philosophy............................................................................ 35

5 Maintenance and Service....................................................37

5.1 Service Strategy..................................................................................37

5.2 Returning for Servicing...................................................................... 37

5.3 Cleaning...............................................................................................38

5.4 Calibration Interval............................................................................. 38

5.5 Discarding the Product...................................................................... 38

5.6 Spare Parts.......................................................................................... 38

6 Functional Check.................................................................41

Index..................................................................................... 42

Product Description

R&S®RT-ZS60

5User Manual 1418.7342.02 ─ 04

1 Product Description

1.1 Key Features and Key Characteristics

The R&S RT-ZS60 is a single-ended active voltage probe with high input impe­dance. It is used for ground-referenced voltage measurements from DC to 6 GHz.
The R&S RT-ZS60 is optimized for single-ended measurements in environments
characterized by 50 Ω impedance.

The comprehensive accessory set allows this probe to be connected to a wide
variety of devices under test (DUT), not impairing the short rise time and the low
input capacitance. Provided with special features such as the R&S ProbeMeter
and the micro button, the R&S RT-ZS60 is designed to meet tomorrow's chal­lenges in probing.

Since the probe is equipped with Rohde & Schwarz probe interface, it can be
connected to any Rohde & Schwarz base unit that is compatible with this inter­face. When connected to the front panel of an R&S oscilloscope, the probe is
controlled via the software menus of the oscilloscope.

Using a specially developed adapter (see Chapter 1.4.2, "Optional Accessories",
on page 12), the probe can be connected to any other base unit.

1.1.1 Key Characteristics

The key characteristics of the probe are the following:

Key Features and Key Characteristics

Product Description

R&S®RT-ZS60

6User Manual 1418.7342.02 ─ 04

Bandwidth DC to 6 GHz

Dynamic range ±8 V with ±10 V offset capability

16 V AC (Vpp)

Maximum non-destructive input voltage ±30 V

Input resistance 1 MΩ

Input capacitance 0.3 pF

R&S ProbeMeter, measurement error <0.1 %

Extremely low zero and gain errors throughout the entire temperature range, no significant tem­perature drift

Extremely low noise and virtually no harmonic distortions

Micro button

Rohde & Schwarz probe interface

1.1.2 Key Features

Micro button

The micro button at the probe head can remotely control different functions on the
base unit. The assigned function is configured via the base unit.

For details, see Chapter 2.3.2, "Micro Button", on page 17.

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 dis­played on the screen of the Rohde & Schwarz oscilloscope.

For details, see Chapter 2.3.4, "R&S ProbeMeter", on page 18.

Data memory

The probe has an integrated data memory, containing the individual probe correc­tion parameters (e.g. gain, delay, offset). These parameters are read out and pro­cessed 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-ZS60

7User Manual 1418.7342.02 ─ 04

1.2 Unpacking

The carrying case contains the following items:

●

R&S RT-ZS60 active voltage probe

●

Carrying case

●

Accessory boxes

●

User manual

●

R&S RT-ZS60 data sheet

●

Calibration certificate

●

Documentation of calibration values (if
ordered)

1.2.1 Inspecting the Contents

●

Inspect the package for damage.
Keep the package and the cushioning material until the contents have been
checked for completeness and the device has been tested.
If the packaging material shows any signs of stress, notify the carrier and your
Rohde & Schwarz service center. Keep the package and cushioning material
for inspection.

●

Inspect the probe.
If there is any damage or defect, or if the R&S RT-ZS60 active voltage probe
does not operate properly, notify your Rohde & Schwarz service center.

●

Inspect the accessories.
If the contents are incomplete or damaged, notify your Rohde & Schwarz ser­vice center.
Accessories supplied with the device are listed in Chapter 1.4.1, "Accessories

Supplied", on page 10.

Unpacking

Product Description

R&S®RT-ZS60

8User Manual 1418.7342.02 ─ 04

1.3 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.

1.3.1 Probe Head

The small and lightweight probe head is designed for easy handling and high-per­formance 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

2

3

(1) Signal socket
(2) Ground socket
(3) Micro button
The accessories supplied for the probe head

sockets are listed in Chapter 1.4.1, "Accesso-

ries Supplied", on page 10.

Signal and ground sockets are compatible with

0.64 mm (25 mil) square pins and 0.6 mm to

0.8 mm (24 mil to 35 mil) round pins.

Description of the Probe

Product Description

R&S®RT-ZS60

9User Manual 1418.7342.02 ─ 04

Special accessories for signal socket

The signal socket of the R&S RT-ZS60 has a special design to ensure opti­mal performance. The signal socket is 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-ZS60 provided by
Rohde & Schwarz.

1.3.2 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 pro­vides 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 gen­erated in the probe box. This approach ensures that it will be possible to operate
future probes on any base unit that features a Rohde & Schwarz probe interface.

(1) Rohde

& Schwarz probe interface with

7 mm (276 mil) coaxial connector and 6 pogo
pins

(2) Release knob

1.4 Accessories and Items

The figure below shows all accessories that are available for the R&S RT-ZS60
active voltage probe.

Accessories and Items

Product Description

R&S®RT-ZS60

10User Manual 1418.7342.02 ─ 04

lead,
15 cm / 5.9 in

ground adapter,
square pin

ground pin, pogo

ground pin, solder in

signal adapter, square pin

signal pin

signal pin, solder in

lead
6 cm / 2.4 in

micro clip

mini clip

marker band kit

Figure 1-1: Available accessories

1.4.1 Accessories Supplied

The following table shows the accessories supplied with the R&S RT-ZS60 active
voltage probe.

Table 1-1: Accessories supplied

Item Quantity Description

100 Signal pin, solder in

5 Signal pin

Accessories and Items

Product Description

R&S®RT-ZS60

11User Manual 1418.7342.02 ─ 04

Item Quantity Description

2 Signal adapter, square pin

20 Ground pin, solder in

5 Ground pin, pogo

2 Ground adapter, square pin

2 Lead, 6 cm / 2.4 in

2 Lead, 15 cm / 5.9 in

2 Mini clip

Accessories and Items

Product Description

R&S®RT-ZS60

12User Manual 1418.7342.02 ─ 04

Item Quantity Description

2 Micro clip

1 Marker band kit

1 Carrying case with foam inlay

For a list of spare parts, see Chapter 5.6, "Spare Parts", on page 38.

1.4.2 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 1-2: R&S RT-ZA4 mini clips

Item Quantity Description

Mini clip 10 Contains mini clips.

Table 1-3: R&S RT-ZA5 micro clips

Item Quantity Description

Micro clip 4 Contains micro clips.

Accessories and Items

Product Description

R&S®RT-ZS60

13User Manual 1418.7342.02 ─ 04

Table 1-4: R&S RT-ZA6 lead set

Item Quantity Description

Lead, 6 cm / 2.4 in
Lead, 15 cm / 5.9 in

5
5

Contains short and long leads.

Table 1-5: R&S RT-ZA9 probe box to N / USB adapter

The adapter can be used to connect the R&S RT­ZS60 active voltage 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.

1.4.3 Service Accessories

To order accessories for servicing the probe, contact your Rohde & Schwarz ser­vice center. The following accessories are available:

Table 1-6: Service accessories

Item Description

R&S RT-ZK2 The service kit is used to calibrate the probe, to do perform-

ance tests, and for servicing. The service kit includes all
adapters and accessories to connect the probe to the
required measuring instruments.

R&S RT-ZS60 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

Putting into Operation

R&S®RT-ZS60

14User Manual 1418.7342.02 ─ 04

2 Putting into Operation

The probe is designed for usage with oscilloscopes that have a Rohde & Schwarz
probe interface. Supported Rohde & Schwarz oscilloscopes are listed in the pro­be's data sheet.

Read and observe the "Basic Safety Instructions" that are delivered with the
probe as a printed brochure. Also, read and observe the safety instructions of the
oscilloscope the probe is connected to.

Maximum non-destructive input voltage

The maximum non-destructive input voltage is ±30 V. A higher input voltage
can destroy the probe.

The maximum input voltage is derated for higher frequencies. Refer to the
data sheet for further information.

Risk of device damage

The R&S RT-ZS60 can withstand a moderate amount of physical and elec­trical stress. To avoid damage, treat the probe with care:

●

Do not exceed the specified voltage limits.

●

Connect the R&S RT-ZS60 only to an instrument with Rohde & Schwarz
probe interface. Never connect it to a usual BNC jack. Although the
7 mm coaxial connector 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-ZS60 can withstand a higher frequency limit.

●

Avoid excessive strain on the probe cable, and kinking.

●

Prevent the adapter from receiving mechanical shock.

●

Do not spill liquids on the probe.

●

Store the probe in a shock-resistant case, e.g. in the foam-lined ship­ping case.

Putting into Operation

R&S®RT-ZS60

15User Manual 1418.7342.02 ─ 04

During usage, the probe slightly heats up. Warming is normal behavior and not a
sign of malfunction.

Damage caused by electrostatic discharge

Electrostatic discharge (ESD) can damage the electronic components of the
probe and the instrument, and also the device under test (DUT). Electro­static discharge is most likely to occur when you connect or disconnect a
DUT or test fixture to the probe and to the instrument's test ports. To pre­vent electrostatic discharge, use a wrist strap and cord and connect your­self to the ground, or use a conductive floor mat and heel strap combina­tion. Discharge cables and probe tips before you connect them.

2.1 Connecting the Probe to the Oscilloscope

► 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 2-1: Connecting the probe to the Rohde & Schwarz oscilloscope

Connecting the Probe to the Oscilloscope

Putting into Operation

R&S®RT-ZS60

16User Manual 1418.7342.02 ─ 04

► To disconnect the probe:

a) Press and hold the release button (3).
b) Pull the probe box away from the oscilloscope.

2.2 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.

The complete probe information is shown in the probe settings dialog. For more
information, refer to the user manual of your oscilloscope.

2.3 Using the Probe

2.3.1 Zero Adjustment

The zero error can impair the measurement results, therefore, correct the zero
error if necessary. The zero error of the probe itself is very small. However, differ­ences in DUT and oscilloscope ground levels can cause larger zero errors visible
on the oscilloscope's screen. If the DUT is not floating but ground-referenced, an
zero adjustment improves the measurement results.

The zero error is corrected at the oscilloscope. Depending on the type of the used
oscilloscope, correction is done automatically using the AutoZero function, or
manually ("Zero Adjust" or similar setting). Refer to the oscilloscope's user man­ual for available functionality and its usage.

1. Connect the probe to the Rohde & Schwarz oscilloscope.

2. Set the oscilloscope to the smallest vertical scale.

3. Short the signal pin and the ground pin together and connect them to the
ground of the DUT.

Using the Probe

Putting into Operation

R&S®RT-ZS60

17User Manual 1418.7342.02 ─ 04

4. Adjust the zero position of the waveform using the appropriate function of the
oscilloscope ("AutoZero", "Zero Adjust" or similar).

The waveform is set to 0 V on the horizontal centerline of the oscilloscope.

2.3.2 Micro Button

The micro button provides easy and quick access to important functions of the
Rohde & Schwarz oscilloscope. After a function has been assigned, pressing the
micro button remotely controls this specific function on the base unit. For exam­ple, "Continuous Run" or "Single" are often assigned to the micro button.

The configuration of the micro button is part of the probe settings of the channel
to which the probe is connected. For more details, see the oscilloscope's user
manual.

2.3.3 Offset Compensation

The offset compensation function can compensate a DC component of the input
signal, even in front of the active amplifier in the probe tip. As a result, the entire
dynamic range of the probe is maintained. This function is useful when measuring
AC signals with high superimposed DC component.

Using the Probe

Putting into Operation

R&S®RT-ZS60

18User Manual 1418.7342.02 ─ 04

Figure 2-2: Offset compensation voltage and dynamic range

There are several ways to set the offset compensation:

●

Use the vertical knob at the oscilloscope if its function is set to offset.

●

Enter the offset value in the channel settings or probe settings on the
R&S RTx.

●

Use the micro button to measure input signals with different DC offsets: assign
"Set offset to mean" to the micro button. See also Chapter 2.3.2, "Micro But-

ton", on page 17.

For more details, see the oscilloscope's user manual.

2.3.4 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 measure­ment is performed continuously and in parallel to the time domain measurement
of the oscilloscope.

Using the Probe

Putting into Operation

R&S®RT-ZS60

19User Manual 1418.7342.02 ─ 04

High-precision measurements are achieved through immediate digitization of the
measured DC voltage at the probe tip.

When the R&S ProbeMeter is active, the measured values are displayed on the
oscilloscope. The R&S ProbeMeter state is part of the probe settings of the chan­nel to which the probe is connected. For details, refer to the user manual of the
Rohde & Schwarz 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 offset, position, vertical scale, hori­zontal scale, and trigger.

●

Independent of probe settings for measurement mode and gain.

●

Measurement range ±8 V + offset compensation setting. Maximum measure­ment accuracy is achieved when offset compensation is switched off.

The R&S ProbeMeter enables the ground-referenced measurement of voltages.
A difference in the ground levels of oscilloscope and DUT can cause an unwan­ted zero error. In this case, correct the zero error, see Chapter 2.3.1, "Zero

Adjustment", on page 16.

Using the Probe

Connecting the Probe to the DUT

R&S®RT-ZS60

20User Manual 1418.7342.02 ─ 04

3 Connecting the Probe to the DUT

This chapter describes the different ways of connecting the probe to the DUT. In
addition, the usage of the supplied accessories is explained.

To achieve optimum RF performance, the connections must be as short as possi­ble. If long connections cannot be avoided, they have to be preferably used for
the ground socket.

Risk of injuries

The included probe pins are exceptionally sharp and must be handled with
extreme care. To prevent injuries, always use tweezers when inserting or
removing pins.

Some solder-in accessories are very fine and sensitive. Stabilize the probe
using appropriate means (e.g. adhesive pads, probe positioner) in order to
protect the solder joint from excessive mechanical stress.

Pins

Signal pin and ground pin, pogo

Using the signal pin and ground pin, manual
measurements can be performed without or
with only minor limitation of the measurement
bandwith. Best results are achieved if the dis­tance between signal and ground is small.
Even with maximum distance, rise times
shorter 70 ps can be reached.

Because the spring-loaded ground pin com­pensates for minor unevenness and move­ments, this pin can establish a firm contact
with the test point. It fits into the ground socket
of the probe head.

The distance to the signal pin can be varied by
turning the ground pin.

Distance range:
0 mm to 10 mm (0 mil to 400 mil)

Connecting the Probe to the DUT

R&S®RT-ZS60

21User Manual 1418.7342.02 ─ 04

Signal pin, solder in, and ground pin, solder-in

Using two solder-in pins for ground and signal,
the R&S RT-ZS60 is soldered directly into the
circuit.

The pins can be exchanged on the probe and
can remain in the circuit. Thus, you can plug
the probe on different test points.

Use tweezers to insert the solder-in pins into
the sockets on the probe, and then cut to the
appropriate length. Keep the pins as short as
possible.

The fine wires on this adapter are best suited
to make secure contact with small contact
points, such as SMT components or IC pins.

Alternatively, the signal pin has a solder tail for
direct soldering of wires.

Distance range:
0 mm to 20 mm (0 mil to 800 mil)

Connecting the Probe to the DUT

R&S®RT-ZS60

22User Manual 1418.7342.02 ─ 04

Signal adapter, square pin, and ground adapter, square pin

Using two square-in pin adapters for ground
and signal, the probe can be connected
directly to a pin strip.

The sockets are compatible with 0.64 mm
(25 mil) square pins and 0.6 mm to 0.8 mm
(24 mil to 35 mil) round pins.

The distance between the signal and ground
adapter can be adjusted by turning the ground
adapter.

Distance range:

2.54 mm to 10.16 mm (100 mil to 400 mil)

Connecting the Probe to the DUT

R&S®RT-ZS60

23User Manual 1418.7342.02 ─ 04

Leads

Short and long lead

The lead provides a flexible connection to the
DUT. It is plugged onto a pin on the DUT and
can be used to connect either the signal
socket or the ground socket. In addition, it
allows micro and mini clips to be connected to
the probe.

Connencting a lead to the signal socket of the
R&S RT-ZS60 requires a signal adapter,
square pin.

Length:
Short lead: 6 mm (236 mil)
Long lead: 15 mm (591 mil)

Connecting the Probe to the DUT

R&S®RT-ZS60

24User Manual 1418.7342.02 ─ 04

Clips

Mini and micro clips

The mini clip is designed for probing large IC
pins, wires and through-hole components.

The micro clip is designed for probing IC pins
and thin wires in fine-pitch applications.

Clips can be used to contact ground and sig­nal.

To connect a clip to the ground socket, a lead
is required.

To connect a clip to the signal socket, the sig­nal adapter, square pin, is required.

Measurement Principles

R&S®RT-ZS60

25User Manual 1418.7342.02 ─ 04

4 Measurement Principles

The R&S RT-ZS60 active voltage probe provides an electrical connection
between the DUT and the oscilloscope. The probe transfers the voltage of the
electrical signal tapped off the DUT to the oscilloscope, where it is displayed
graphically. Although a probe has a wide variety of specifications, these specifica­tions can be grouped into two classes of basic requirements:

●

High signal integrity of the transferred signal:
With an ideal probe, the output signal that is transferred to the base unit is
identical to the input signal between the probe tips, and signal integrity is
extremely high. Every real probe, however, transfers the input signal in altered
form. A good probe causes only minimum alterations.
How the probe can fulfill this requirement is mainly determined by its band­width.

●

Low loading of the input signal:
Every probe is a load for the signal to be measured. The signal to be mea­sured changes when the probe is connected. A good probe causes only a
minimum change to the signal, so that the function of the DUT is not adversely
affected.
How the probe can fulfill this requirement is mainly determined by its input
impedance.

The parameters of a probe are usually specified for a minimally short connection
between the probe and the DUT. With longer connections, the connection induc­tance has a significant effect on the measurement.

The high-frequency behavior of active probes is typically characterized in a 50 Ω
measurement environment. The probe is connected to a 50 Ω line that is fed by a
source with 50 Ω internal impedance and that is terminated into 50 Ω.

The Figure 4-1 shows the equivalent circuit model of a probe that is connected to
the DUT.

Measurement Principles

R&S®RT-ZS60

26User Manual 1418.7342.02 ─ 04

Figure 4-1: Equivalent circuit model of the R&S RT-ZS60 probe

Table 4-1: Designations

Abbreviation Description

V

S

Voltage at the test point without probe connected

V

in

Voltage at the test point with probe connected,
corresponds to the input voltage of the probe

R

S

Source resistance of the DUT

R

L

Load resistance of the DUT

R

in

DC input resistance

C

in

RF input capacitance of the probe

C

LF

LF input capacitance of the probe

R

RF1

, R

RF2

RF input resistance of the probe

L

con

Parasitic inductance of the ground connection

In a 50 Ω system, the output resistance of the source, the load resistance and the
characteristic impedance of all lines equal exactly 50 Ω. However, the behavior of
the probe in the circuit is determined by the effective source impedance which is
the impedance present in the DUT between the probe tip and ground.

Effective source impedance:





25||

LSS

RRR

Measurement Principles

R&S®RT-ZS60

27User Manual 1418.7342.02 ─ 04

4.1 Signal Integrity of the Transferred Signal

The following sections describe the effect that bandwidth and connection induc­tance have on signal integrity.

4.1.1 Bandwidth

The bandwidth BW of a probe is one of its specific parameters. The bandwidth of
the probe and the bandwidth of the base unit together form the system band­width. The following explanations refer to the probe itself, but can also be applied
to the entire system.

Figure 4-2: Amplitude/frequency response of the R&S RT-ZS60

The bandwidth:

●

Specifies the maximum frequency at which a purely sinusoidal signal is still
transferred at 70 % (–3 dB) of its amplitude.

Signal Integrity of the Transferred Signal

Measurement Principles

R&S®RT-ZS60

28User Manual 1418.7342.02 ─ 04

●

Specifies the transferable spectrum for other waveforms. E.g., with square
wave signals, the fifth harmonic should still be within the bandwidth for a high
signal integrity.

●

Determines the minimum measurable signal rise time. The rise time t

rise

of the

probe is inversely proportional to its bandwidth. The following approximation
applies:

BW

t

rise

4.0



In addition to bandwidth, a constant amplitude/frequency response of the probe is
decisive for high signal integrity. The Figure 4-2 shows the typical amplitude/
frequency response of an R&S RT-ZS60 active voltage probe. All frequency com­ponents are transferred with the same gain so that the input signal is displayed
without distortion.

The Figure 4-3 shows a typical step response of an R&S RT-ZS60 active voltage
probe.

Figure 4-3: Step response of the R&S RT-ZS60

Signal Integrity of the Transferred Signal

Measurement Principles

R&S®RT-ZS60

29User Manual 1418.7342.02 ─ 04

4.1.2 Connection Inductance

The connection inductance L

con

is caused by connecting the probe to the DUT. In

contrast to the probe-specific bandwidth, the connection inductance mainly
depends on the selected type.

The connection inductance:

●

Increases with the length of the connection and the size of the resulting loop
area A.

●

Reduces the usable bandwidth and causes ringing with signals having a short
rise time, due to a series resonance with the input capacitance.

●

Must be as small as possible (short lead length) to maintain high signal integ­rity.

●

Long leads on the signal input are especially problematic.

con

incon

resonance

con

L

BW

CL

f

AL

1

toalproportion

2

1

≈

toalproportion





Figure 4-4: Ground connection and connection inductance

Signal Integrity of the Transferred Signal

Measurement Principles

R&S®RT-ZS60

30User Manual 1418.7342.02 ─ 04

4.1.3 Performance with Different Connection Types

The Table 4-2 shows three types of connection between probe and DUT as well
as the associated rise times, bandwidths, input impedances and overshoots.

Table 4-2: Typical rise time, bandwidth, input impedance and overshoot with different

connection types

No Connection

Type

Connection

Rise
time

Band­width

Min. input

impedance

|Z

min

|

Over­shoot

Signal

socket

Ground

socket

1

signal

pin

ground

pin,

pogo

wide

spacing

64 ps 6 GHz 150 Ω 9 %

narrow

spacing

55 ps 8 GHz 110 Ω 25 %

2

signal

pin, sol-

der in

ground

pin, sol-

der in

short

pins

66 ps 6.5 GHz 155 Ω 8 %

long
pins

70 ps 4.5 GHz 235 Ω 11 %

3

signal

adapter,

square

pin

ground

adapter,

square

pin

wide

spacing

64 ps 5.5 GHz 120 Ω 11 %

narrow

spacing

52 ps 9 GHz 75 Ω 34 %

Signal Integrity of the Transferred Signal

Measurement Principles

R&S®RT-ZS60

31User Manual 1418.7342.02 ─ 04

Figure 4-5: Step response of the R&S RT-ZS60 with a type 1 connection

Figure 4-6: Step response of the R&S RT-ZS60 with a type 2 connection

Signal Integrity of the Transferred Signal

Measurement Principles

R&S®RT-ZS60

32User Manual 1418.7342.02 ─ 04

Figure 4-7: Step response of the R&S RT-ZS60 with a type 3 connection

4.2 Signal Loading of the Input Signal

The previous section dealt with the transfer function and step response of the
probe. This section describes how the probe influences the input signal.

4.2.1 Input Impedance

The input signal loading caused by the probe is determined by its input impe­dance Zin. The Figure 4-1 presents an equivalent circuit model.

Zin consists of the following probe-specific parameters.

●

Input resistance R

in

●

LF input capacitance C

LF

●

RF resistance R

RF1

+ R

RF2

●

RF input capacitance C

in

●

Minimum input impedance |Z

min

|

Signal Loading of the Input Signal

Measurement Principles

R&S®RT-ZS60

33User Manual 1418.7342.02 ─ 04

The resulting input impedance versus frequency is indicated in Figure 4-8. The
trace shows five characteristic areas, which can be assigned to Rin, CLF, RRF, Cin,

and |Z

min

|. The resulting loading of a step signal at the input of the probe is given

in Figure 4-9.

The connection inductance L

con

has only a minor effect on the signal loading and

is therefore not considered in the following.

Figure 4-8: Magnitude of the input impedance of the R&S RT-ZS60 probe as a function of

frequency

Signal Loading of the Input Signal

Measurement Principles

R&S®RT-ZS60

34User Manual 1418.7342.02 ─ 04

Figure 4-9: Signal loading caused by the R&S RT-ZS60 probe at an effective source impe-

dance of 25 Ω

4.2.1.1 Input Resistance

The input resistance Rin determines the loading of the DUT at DC and low fre­quencies (< 4 kHz). A low input resistance can potentially disturb measurements

of high-frequency signals as it influences the DC operating point of active compo­nents. This effect is negligible for most applications involving the R&S RT-ZS60
probe due to the high input resistance of the probe (1 MΩ).

4.2.1.2 LF Capacitance

The LF capacitance CLF causes the input impedance to decrease in the low fre­quency range (4 kHz to 20 MHz). The LF capacitance affects the settling time of

the loaded input voltage for fast transients, see Figure 4-9.

Signal Loading of the Input Signal

Measurement Principles

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35User Manual 1418.7342.02 ─ 04

4.2.1.3 RF Resistance

R

RF1

and R

RF2

(summarized RRF) determine the input impedance in the frequency

range from 20 MHz to 2 GHz. Due to the constantly high input impedance of
300 Ω over the whole range, the loading of high-frequency signals in 50 Ω envi­ronments is very small.

4.2.1.4 Input Capacitance Cin and Minimum Input Impedance |Z

min

|

The input capacitance Cin causes the input impedance to decrease for high fre­quencies above 2 GHz. Cin is very low - Typically under 300 fF.

The minimum input impedance |Z

min

| mainly depends on the connection induc-

tance and the connection type. An overview is given in Table 4-2.

4.3 Probing Philosophy

The previous sections explained that probes exert a load on the signal to be mea­sured and change its characteristic. The signal at the test point where the probe
makes contact (Vin) is therefore different from the signal that was present before

the probe was connected (VS). This effect cannot be avoided and occurs with all
real probes – independent of type and manufacturer.

As a result, there are different opinions which signal is the better output of the
probe:

●

The initial signal that is not loaded by the probe (VS), and that corresponds to
the signal at the test point without the probe being connected.

●

The input signal that is loaded with the input impedance of the probe (Vin) and
that is present between the probe tips.

Both approaches are physically correct and have their individual advantages and
disadvantages. In theory, it is even possible to convert mathematically the two
measurement results into each other, but conversion is a complex transformation
to and from the frequency domain. Probe manufacturers use one or the other of
these two approaches.

Rohde & Schwarz has decided in favor of the user-friendly approach. In our opin­ion, most users want to know the signal present in the DUT before it was altered

Probing Philosophy

Measurement Principles

R&S®RT-ZS60

36User Manual 1418.7342.02 ─ 04

by the influence of the probe. Their goal is to characterize the DUTs, not the
probe.

If measurements are carried out in a 50 Ω environment, the signal displayed on
the oscilloscope's screen is always a direct representation of the unloaded signal
VS, see Figure 4-10.

Figure 4-10: Unloaded and loaded input signal and step response using the example of

R&S RT-ZS60

Probing Philosophy

Maintenance and Service

R&S®RT-ZS60

37User Manual 1418.7342.02 ─ 04

5 Maintenance and Service

5.1 Service Strategy

Like all Rohde & Schwarz products, Rohde & Schwarz probes and adapters are
of high quality and require only minimum service and repair. However, if service is
needed, contact your Rohde & Schwarz service center. Return a defective prod­uct to the Rohde & Schwarz service center for diagnosis and exchange.

You can return the R&S RT-ZS60 active voltage probe for calibration. The service
personnel carry out the required tests.

5.2 Returning for Servicing

Use the original packaging to return your R&S RT-ZS60 to your
Rohde & Schwarz service 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.

Returning for Servicing

Maintenance and Service

R&S®RT-ZS60

38User Manual 1418.7342.02 ─ 04

5.3 Cleaning

Product damage caused by cleaning agents

Cleaning agents contain substances that can damage the product, for
example, solvent can damage the labeling or plastic parts.

Never use cleaning agents such as solvents (thinners, acetone, etc.), acids,
bases or other substances.

To clean the exterior of the product, use a soft cloth moistened with either distilled
water or isopropyl alcohol. Before using the product again, make sure to dry it
completely.

5.4 Calibration Interval

The recommended calibration interval for R&S RT-ZS60 active voltage probe is
two years. For servicing, send the probe to your nearest Rohde & Schwarz ser­vice center (see Chapter 5.2, "Returning for Servicing", on page 37).

5.5 Discarding the Product

Handle and dispose the product in accordance with local regulations.

5.6 Spare Parts

The following accessories can be ordered at the Rohde & Schwarz service cen­ter. Use the order numbers provided in the following table.

Spare Parts

Maintenance and Service

R&S®RT-ZS60

39User Manual 1418.7342.02 ─ 04

Table 5-1: Accessory spare parts

Pos. Item Description Material number

1 Signal pin, solder in 1417.0838.00

2 Signal pin 1175.7651.00

3 Signal adapter, square pin 1175.7668.00

4 Ground pin, solder in 1417.0538.00

5 Ground pin, pogo 1175.7716.00

6 Ground adapter, square pin 1175.7597.00

7 Lead, 6 cm / 2.4 in 1416.0128.00

8 Lead, 15 cm / 5.9 in 1416.0134.00

Spare Parts

Maintenance and Service

R&S®RT-ZS60

40User Manual 1418.7342.02 ─ 04

Pos. Item Description Material number

9 Mini clip 1416.0105.00

10 Micro clip 1416.0111.00

11 Marker band kit 1416.0205.00

12 Pogo pin Pogo pin connector, 6 pins 3584.6396.00

13 R&S RT-ZK2 R&S RT-ZK2 service kit 1410.5305.02

Table 5-2: Parts for ESD prevention

Pos. Item Material number

1 ESD wrist strap 0008.9959.00

2 ESD grounding cable 1043.4962.00

Spare Parts

Functional Check

R&S®RT-ZS60

41User Manual 1418.7342.02 ─ 04

6 Functional Check

The functional check confirms the basic operation of the R&S RT-ZS60 active
voltage probe. The functional check is not suitable for verifying compliance with
the probe specifications.

1. Connect the R&S RT-ZS60 probe to a Rohde & Schwarz oscilloscope as
described in Chapter 2.1, "Connecting the Probe to the Oscilloscope",
on page 15.

2. Connect the signal pin to the square wave output of the oscilloscope.

3. Connect the ground pin to the probe ground connector of the oscilloscope.

4. Press the [Preset] key and then the [Autoset] key on the oscilloscope.

A square wave with 1 V amplitude between 0 V and 1 V is displayed on the
display.

Index

R&S®RT-ZS60

42User Manual 1418.7342.02 ─ 04

Index

A

Accessories ............................................. 10

Spare Parts .........................................38

AutoZero ..................................................16

B

Bandwidth ............................................6, 27

C

Cleaning .................................................. 38

Clips .................................................. 12, 24

Connecting to DUT ..................................20

Connecting to oscilloscope ......................15

Connection inductance ............................29

D

Data memory .............................................6

DC component of input signal ................. 17

DC measurement .................................... 18

Dynamic range .................................... 6, 17

E

Electrostatic discharge ............................ 15

ESD ......................................................... 15

F

Functional check ..................................... 41

I

Inductance ...............................................29

Input capacitance ...................................... 6

Input impedance ......................................32

Input resistance ................................... 6, 34

L

Leads .................................................13, 23

LF capacitance ........................................ 34

M

Micro button .........................................6, 17

N

N/USB adapter ........................................ 13

O

Offset compensation ............................... 17

P

Pins

Inserting and removing ....................... 20

Usage ................................................. 20

Probe box .................................................. 9

Probe head ................................................8

Probe identification ..................................16

ProbeMeter ..........................................6, 18

Probing principles ....................................25

Product description ....................................5

R

RF resistance .......................................... 35

S

Service kit ................................................13

Service manual ........................................13

Signal integrity .........................................27

Signal loading ..........................................32

Spare parts ..............................................38

Step response ......................................... 28

U

Unpacking ................................................. 7

Using accessories

Ground adapter, square pin ................ 22

Ground pin, pogo ................................ 20

Ground pin, solder in .......................... 21

Leads .................................................. 23

Micro clip .............................................24

Mini clip ...............................................24

Signal adapter, square pin .................. 22

Signal pin ............................................ 20

Signal pin, solder in ............................ 21

Z

Zero error correction ................................16