background image

Measurement Principles

R&S

®

RT-ZD40

33

User Manual 1410.5363.02 ─ 05

5.1

 

Signal Integrity of the Transferred Signal

The following sections describe the effect that bandwidth, connection inductance
and common mode rejection ratio have on signal integrity.

5.1.1

 

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 band-
width. The following explanations refer to the probe itself, but can also be applied
to the entire system.

Figure 5-2: Amplitude frequency response of the R&S

 

RT-ZD40

The bandwidth:

Specifies the maximum frequency at which a purely sinusoidal signal is still
transferred at 70

 

% (–3

 

dB) of its amplitude.

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:

Signal Integrity of the Transferred Signal

Содержание RT-ZD40

Страница 1: ...R S RT ZD40 Active Differential Probe User Manual User Manual Version 05 1410536302 ÃÍ2 ...

Страница 2: ...info rohde schwarz com 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 1410 5363 02 Version 05 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...

Страница 3: ...Head 8 1 3 2 Probe Box 9 1 4 Accessories and Items 10 1 4 1 Accessories Supplied 11 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 4 Offset Compensation 17 2 4 1 Differential Offset 17 2 4 2 Common Mode Of...

Страница 4: ...ed Signal 33 5 1 1 Bandwidth 33 5 1 2 Connection Inductance 34 5 1 3 CMRR 37 5 2 Signal Loading of the Input Signal 37 5 2 1 Signal Loading for Differential Input Signals 38 5 2 2 Signal Loading for Non Differential Input Signals 40 5 3 Probing Philosophy 40 6 Maintenance and Service 42 6 1 Cleaning 42 6 2 Contacting Customer Support 42 6 3 Returning for Servicing 43 6 4 Calibration Interval 44 6 ...

Страница 5: ...ory 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 theRohde Schwarz probe interface It can be con nected to any Rohde Schwarz instrument that is compatible with this interface When connected...

Страница 6: ...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 volt...

Страница 7: ...T ZD40 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 pa...

Страница 8: ...sy 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 1 4 1 Accesso ries Su...

Страница 9: ...tors 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 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 coa...

Страница 10: ...ure below shows all accessories that are available for the R S RT ZD40 differential probe Figure 1 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 Accessories and Items ...

Страница 11: ...ows the accessories supplied with the R S RT ZD40 differ ential probe Table 1 1 Accessories supplied Item Quantity Description 100 Signal pin solder in 2 Socket adapter variable spacing 2 Browser adapter rigid 2 Browser adapter spring loaded 2 Lead 6 cm 2 4 in 1 Lead 15 cm 5 9 in 2 Mini clip Accessories and Items ...

Страница 12: ... 44 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 Accesso...

Страница 13: ...her 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 conven tional PC 1 4 3 Service Accessories To order accessories for servicing the probe contact your Rohde Schwarz ser vice center The following accessories are available Table 1 7 Service accessories Item Description R S RT ZK2 The service kit is us...

Страница 14: ...n and ground The maximum input voltage is derated for higher frequen cies Refer to the data sheet for further information Risk of device damage The R S RT ZD40 can withstand a moderate amount of physical and elec trical stress To avoid damage treat the probe with care Do not exceed the specified voltage limits Connect the R S RT ZD40 only to an instrument with Rohde Schwarz probe interface Never c...

Страница 15: ... connect or disconnect a DUT or test fixture to the probe and to the instrument s test ports To pre vent electrostatic discharge use a wrist strap and cord and connect your self to the ground or use a conductive floor mat and heel strap combina tion 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 prob...

Страница 16: ...our 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 differ ences 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 imp...

Страница 17: ...ngle 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 4 Offset Compensation The R S RT ZD40 features two offset compensation functions a differential off set compensation and a common mode offset compensation Each function com pensates a par...

Страница 18: ...for a single ended measurement negative input connected to ground using an R S RT ZD10 20 30 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 Rohde Schwarz oscilloscope Use the micro button to measure input signals with different DC offsets assign ...

Страница 19: ...ssary to set a common mode offset compensation The R S RT ZD40 measures only differential input signals Common mode signals are suppressed by the probe Therefore the common mode offset compensation is not directly visible on the oscilloscope screen see also Chapter 4 2 Dynamic Range and Operating Voltage Window on page 29 An incorrect common mode offset compensation can lead to unwanted clipping e...

Страница 20: ... page 27 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 chan nel 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 oscillos...

Страница 21: ...mmon mode offset compensa tion setting The R S ProbeMeter enables the ground referenced measurement of voltages A difference in the ground levels of oscilloscope and DUT can cause an unwan ted zero error In this case correct the zero error see Chapter 2 3 1 Zero Adjustment on page 16 Offset Compensation ...

Страница 22: ... 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 solder in Use tweezers to insert the solder in pins onto the pins inside the signal sockets of the probe and then cut to the appropria...

Страница 23: ... pins can be adjus ted First insert one part on the appropriate socket Then insert the second part to the other socket and make sure that the levers are symmetrical and the cogs are meshing To adjust the distance between the sockets pins turn the levers A built in stop prevents unwanted turning of the signal pins when prob ing Socket adapter The socket adapter is designed to plug the probe onto pi...

Страница 24: ...d move ments it can establish a firm contact to the test point Distance range 0 mm to 6 mm 0 mil to 240 mil Leads and clips 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 sockets or the ground socket In addition it allows micro and mini clips to be connected to the probe Length Short lead 60 mm...

Страница 25: ...anual 1410 5363 02 05 Mini clip The mini clip is designed for probing large IC pins wires and through hole components The mini clip is connected to the ground socket using a lead or it is connected to the signal sockets using the socket adapter and a lead ...

Страница 26: ... 5363 02 05 Micro clip The micro clip is designed for probing IC pins and thin wires in fine pitch applications The micro clip is connected to the ground socket using a lead or it is connected to the signal sockets using the socket adapter directly or using a lead ...

Страница 27: ...ween the positive and negative signal sockets Positive single ended input voltage Vp Voltage between the positive signal socket and the ground socket Negative single ended input voltage Vn Voltage between the negative signal socket and the ground socket Common mode input voltage Vcm Mean voltage of positive and negative signal sockets referred to the ground socket respectively Two of these voltage...

Страница 28: ...s only on the differential input voltage Vin between positive and negative input and suppresses the com mon mode voltages This is equivalent to an infinite common mode rejection ratio CMRR In contrast real probes have a finite CMRR resulting in a small part of the com mon mode voltage visible in the output signal The CMRR is defined as the ratio of the amplifications of differential and common mod...

Страница 29: ... or differential mode range designates the maximum dif ferential voltage Vin that may occur between the positive and negative signal pin At the same time the two voltage values at each of the two signal pins Vp and Vn referenced to the common ground must not exceed a specific limit value This limitation is referred to as the operating voltage window some manufac turers also use the less precise te...

Страница 30: ...o beMeter is a convenient way to detect breaches of the operating voltage window owing to excess DC common mode voltages 4 3 Ground Connection It is typically not necessary to connect the ground socket of the probe to the ground of the DUT as long as the DUT itself is grounded If the ground of the DUT is floating such as in the case of battery operation high static potentials between the DUT groun...

Страница 31: ...requirement is mainly determined by its band width and CMRR Low loading of the input signal Every probe is a load for the signal to be measured The signal to be mea sured 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 im...

Страница 32: ...ntial voltage between the test point without probe connected Vin Differential voltage at the test point with probe connected corre sponds to the input voltage of the probe RS Differential source resistance of the DUT RL Differential load resistance of the DUT R1 R2 Probe specific input resistance C1 C2 Probe specific input capacitance Lcon Parasitic inductance of the probe connection ...

Страница 33: ...lanations refer to the probe itself but can also be applied to the entire system Figure 5 2 Amplitude frequency response of the R S RT ZD40 The bandwidth Specifies the maximum frequency at which a purely sinusoidal signal is still transferred at 70 3 dB of its amplitude Specifies the transferable spectrum for other waveforms E g with square wave signals the fifth harmonic should still be within th...

Страница 34: ...same gain so that the input signal is displayed with out distortion Figure 5 3 Step response of the R S RT ZD40 5 1 2 Connection Inductance The connection inductance Lcon 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 ...

Страница 35: ...oportion Figure 5 4 Ground connection and connection inductance using the example of R S RT ZD10 20 30 The Table 5 2 shows different types of connections between the probe and DUT as well as the associated connection inductance Lcon The table also includes typ ical bandwidth values rise time values and the step responses for each connec tion in conjunction with an R S RT ZD40 Signal Integrity of t...

Страница 36: ...ype of connection Connection inductance L con Typ bandwidth and rise time Step response Very short signal pins solder in 5mm 2 nH 5 5 GHz 75 ps Short browser adapters 3 nH 5 GHz 80 ps Long signal pins solder in 10 mm socket adapters variable spac ing 6 nH 3 GHz 150 ps Very long leads micro clips mini clips 60 nH 500 MHz very long settling time Signal Integrity of the Transferred Signal ...

Страница 37: ...o achieve the best possible CMRR the connec tion to the DUT should always be as symmetrical as possible Figure 5 5 Typical CMRR of the R S RT ZD40 probe as a function of frequency 5 2 Signal Loading of the Input Signal The previous section explained the transfer function and step response of the probe This section describes how the probe influences the input signal The input signal loading caused ...

Страница 38: ...ction of frequency The differential input impedance varies greatly versus the frequency and is defined by the following values Differential input resistance Rdm 2 R1 Differential input capacitance Cdm C1 C2 2 Differential RF resistance RRF 2 R2 5 2 1 1 Input Resistance Rdm The input resistance determines the loading of the DUT at DC and very low fre quencies 100 kHz A low input resistance can pote...

Страница 39: ...ce RRF The RF resistance RRF determines the minimum input impedance and thus the maximum loading at very high frequencies above 1 0 GHz Thus the measure ment result depends on the source impedance of the DUT The RF resistance RRF prevents the input voltage from rising immediately to its final value in the case of fast transients The resulting loading of a step signal at the input of the probe is s...

Страница 40: ...s an example the DC input resist ance for several input signals Table 5 3 DC Input Resistance for Various Input Signals Type of input signal Differential Single ended Common mode Input Resistance 1 MΩ 500 kΩ 250 kΩ This table shows that common mode signals suffer the highest loading This char acteristic of all differential probes is particularly bothersome because common mode signals frequently ha...

Страница 41: ...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 opin ion most users want to know the signal present in the DUT before it was altered by the influence of the probe Th...

Страница 42: ... thinners acetone acids and bases can damage the labeling or plastic parts 2 Dry the product completely before using it 6 2 Contacting 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 tele phone support and works with you to find a solution t...

Страница 43: ...warz com China Phone 86 800 810 8228 86 400 650 5896 customersupport china rohde schwarz com 6 3 Returning for Servicing Use the original packaging to return your R S RT ZD40 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 pr...

Страница 44: ... your nearest Rohde Schwarz service center see Chapter 6 3 Returning for Servicing on page 43 6 5 Discarding the Product Handle and dispose the product in accordance with local regulations 6 6 Spare Parts The following accessories can be ordered at the Rohde Schwarz service cen ter Use the order numbers provided in the following table Table 6 1 Accessories spare parts Pos Item Description Material...

Страница 45: ...ariable spacing 1417 0667 00 4 Lead 6 cm 2 4 in 1416 0128 00 6 Lead 15 cm 5 9 in 1416 0134 00 6 Mini clip 1416 0105 00 7 Micro clip 1416 0111 00 8 Marker band kit 1416 0205 00 9 Signal pin solder in 1417 0838 00 10 Pogo pin Pogo pin connector 6 pins 3584 6396 00 11 R S RT ZK2 R S RT ZK2 service kit 1410 5305 02 Spare Parts ...

Страница 46: ...aintenance and Service R S RT ZD40 46 User Manual 1410 5363 02 05 Table 6 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 ...

Страница 47: ...r 2 1 Connecting the Probe to the Oscilloscope on page 15 2 Connect a socket adapter to the signal sockets 3 Using a short lead and a mini clip connect one of the signal sockets to the square wave output of the oscilloscope 4 Using a short lead and a mini clip connect the other signal socket to the probe ground connector of the oscilloscope 5 Press the Preset key and then the Autoset key on the os...

Страница 48: ...arge 15 ESD 15 F Functional check 47 G Ground connection 30 I Inductance 34 Input capacitance 6 Input resistance 6 Input voltages 27 L Leads 13 Loading 37 M Micro button 6 17 N N USB adapter 13 O Operating voltage window 29 P Pins Inserting and removing 22 Probe box 9 Probe head 8 Probe identification 16 ProbeMeter 6 20 Probing principles 31 Product description 5 S Service kit 13 Service manual 13...

Отзывы: