Tektronix AMT75 User manual

Form 080/01
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Instructions
AMT75
75 to 50 Ohm Impedance Adapter
070-9479-00
There are no current European directives that
apply to this product. This product provides cable
and test lead connections to a test object of
electronic measuring and test equipment.

Copyright ©Tektronix, Inc. All rights reserved.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes
that in all previously published material. Specifications and price change privileges reserved.
Printed in the U.S.A.
Tektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070–1000
TEKTRONIX, TEK, and TEKPROBE are registered trademarks of Tektronix, Inc.

WARRANTY
Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and
workmanship for a period of one (1) year from the date of shipment. If a product proves defective during this
warranty period, Tektronix, at its option, either will repair the defective product without charge for parts and labor,
or will provide a replacement in exchange for the defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration
of the warranty period and make suitable arrangements for the performance of service. Customer shall be
responsible for packaging and shipping the defective product to the service center designated by Tektronix, with
shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if the shipment is to a
location within the country in which the Tektronix service center is located. Customer shall be responsible for
paying all shipping charges, duties, taxes, and any other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to repair damage
resulting from attempts by personnel other than Tektronix representatives to install, repair or service the product;
b) to repair damage resulting from improper use or connection to incompatible equipment; c) to repair any
damage or malfunction caused by the use of non-Tektronix supplies; or d) to service a product that has been
modified or integrated with other products when the effect of such modification or integration increases the time
or difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS
OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’
RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND
EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY.
TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR
THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Service Assurance
If you have not already purchased Service Assurance for this product, you may do so at any time during the product’s
warranty period. Service Assurance provides Repair Protection and Calibration Services to meet your needs.
Repair Protection extends priority repair services beyond the product’s warranty period; you may purchase up to three
years of Repair Protection.
Calibration Services provide annual calibration of your product, standards compliance and required audit documentation,
recall assurance, and reminder notification of scheduled calibration. Coverage begins upon registration; you may purchase
up to five years of Calibration Services.
Service Assurance Advantages
HPriced well below the cost of a single repair or calibration
HAvoid delays for service by eliminating the need for separate purchase authorizations from your company
HEliminates unexpected service expenses
For Information and Ordering
For more information or to order Service Assurance, contact your Tektronix representative and provide the information
below. Service Assurance may not be available in locations outside the United States of America.
Name VISA or Master Card number and expiration
Company date or purchase order number
Address Repair Protection (1,2, or 3 years)
City, State, Postal code Calibration Services (1,2,3,4, or 5 years)
Country Instrument model and serial number
Phone Instrument purchase date

AMT75 Impedance Adapter Instructions 1
General Safety Summary
Review the following safety precautions to avoid injury and prevent damage to
this product or any products connected to it. To avoid potential hazards, use this
product only as specified.
Ground the Product. This product is indirectly grounded through the grounding
conductor of the mainframe power cord. To avoid electric shock, the grounding
conductor must be connected to earth ground. Before making connections to the
input or output terminals of the product, ensure that the product is properly
grounded.
Observe All Terminal Ratings. To avoid fire or shock hazard, observe all ratings
and markings on the product. Consult the product manual for further ratings
information before making connections to the product.
The common terminal is at ground potential. Do not connect the common
terminal to elevated voltages.
Do Not Operate Without Covers. Do not operate this product with covers or panels
removed.
Do Not Operate With SuspectedFailures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.
Do Not Operate in Wet/DampConditions.
Do Not Operate in an Explosive Atmosphere.
Keep Product Surfaces Clean and Dry.
Terms in this Manual. These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that could result
in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that could result in
damage to this product or other property.
To Avoid Fire or
Personal Injury
Symbols and Terms

2AMT75 Impedance Adapter Instructions
Contacting Tektronix
Product
Support For application-oriented questions about a Tektronix measure- ment product, call toll free in North America:
1-800-TEK-WIDE (1-800-835-9433 ext. 2400)
6:00 a.m. – 5:00 p.m. Pacific time
Or contact us by e-mail:
[email protected]
For product support outside of North America, contact your
local Tektronix distributor or sales office.
Service
Support Contact your local Tektronix distributor or sales office. Or visit our web site for a listing of worldwide service locations.
http://www.tek.com
For other
information In North America: 1-800-TEK-WIDE (1-800-835-9433)
An operator will direct your call.
To write us Tektronix, Inc.
P.O. Box 1000
Wilsonville, OR 97070-1000

AMT75 Impedance Adapter Instructions 3
AMT75 Impedance Adapter
The AMT75 (Figure 1) is a 75 to 50 Wimpedance adapter with low VSWR
(voltage standing-wave ratio). The adapter allows you to connect video and
communication signals from a 75 Wcoax cable to the 50 Winput of an oscillo-
scope while minimizing aberrations and reflections. The AMT75 adapter fully
complies with ANSI T1.102 and ITU-T G.703
50 WTekProbe output
75 Winput
Figure 1: AMT75 Adapter
CAUTION. The AMT75 adapter contains components that are sensitive to
electrostatic discharge (ESD). To avoid electrostatic damage, observe ESD
precautions when handling the adapter.

AMT75 Impedance Adapter
4AMT75 Impedance Adapter Instructions
Oscilloscope Connections
As shown in Figure 2a, the output of the AMT75 adapter connects directly to the
TekProbe II interface on Tektronix TDS Series oscilloscopes. With the addition
of optional accessories, the AMT75 adapter connects to any instrument with a
50 WBNC or 50 WSMA input. The shell of the input on all oscilloscopes must
connect to earth ground.
When you connect the adapter to instruments with the TekProbe II interface, the
instrument automatically adjusts the scale factor and sets the oscilloscope input
impedance to 50 W.
NOTE. TDS 400 and TDS 400A series oscilloscopes always interpret the
attenuation of the AFTDS adapter as B10. The attenuation of the adapter is
actually B5. When you use this adapter on these oscilloscopes, divide the
measurement (or scale factor) by 2 to obtain the correct value.
When you connect the adapter to instruments that do not have the TekProbe II
interface, make the settings and calculate the amplitude as follows:
HSet the oscilloscope input impedance to 50 Wor use an external 50 W
termination.
HCorrect your measurements for the 5X attenuation factor of the AMT75
adapter.
Displayed Amplitude ×5 = Actual Amplitude
Input Signal Connections
The female BNC input of the AMT75 adapter accepts a male BNC connector.
The signal input cable (source) must be 75 W. See Figure 2b.
CAUTION. To avoid damaging the 75 Winput connector, use accessories that are
specifically designed for 75 Wconnections. Using 50 Wconnectors on the 75 W
input can damage the 75 Wconnector and degrade the VSWR of the AMT75
adapter.
Instruments with
TekProbe II
Instruments without
TekProbe II

AMT75 Impedance Adapter
AMT75 Impedance Adapter Instructions 5
D-1
D-2
DS-3
DS-4
STS-1
STS-3/STM-1
E-2
E-3
E-4
b) 75 WInput signal connections
50 SMA
input
50 TekProbeoutput
75 BNC Input
75 
Impedance Standard Data Rate (Mb/s)
270
143
44.736
139.264
51.84
155.51
8.448
34.368
139.264
Connection to Tektronix TDS Series
(with the TekProbe II Interface)
TekProbe input
DITS
template
testsignal
BNCtoSMA 50 terminator
50 BNC
input 1 MBNC input
50 BNC Male to BNC Female
AMT75
a) 50 WOscilloscope connections
Connectionstootheroscilloscopes
(without the TekProbe II Interface)
75 BNC Male to BNC Male
Figure 2: Connecting the AMT75 adapter

AMT75 Impedance Adapter
6AMT75 Impedance Adapter Instructions
Specifications
This section contains the specifications and compliances for the AMT75
Impedance Adapter. All specifications are guaranteed unless noted as “typical.”
Typical specifications are provided for your convenience but are not guaranteed.
Specifications that are marked with the nsymbol are checked in the Perfor-
mance Verification on page 8.
Specification/compliance Description
Communicationand video standards D-1 (270Mb/s) STS-3/STM-1 (155.51Mb/s)
D-2 (143Mb/s) E-2 (8.448Mb/s)
DS-3 (44.736Mb/s) E-3 (34.368Mb/s)
DS-4 (139.264Mb/s) E-4 (139.264Mb/s)
STS-1 (51.84Mb/s)
Compliancewithindustrystandards ANSI T1.102 and ITU-T G.703
nInput impedance 75 ±1.5% at DC
Input VSWR (return loss), typical ≤1.1:1 (≥26.45 dB) to 1 GHz (see Figure 3)
nOutput impedance 50 ±1.5% at DC
nAttenuationaccuracy 5X (–14 dB) ±1.5% at DC
Bandwidth,(–3dB)typical ≥1.0 GHz
Rise time, typical < 350 ps (calculated from the formula .35/bandwidth = rise time)
Ratedinput voltage (Power) ≤5 VDC or VACRMS (333 mW)
Temperature
Operating
Nonoperating
Class 5 Limits
0_C to + 50_C
–55_C to + 75_C
Humidity Operating
Nonoperating
Class 5 Limits
+30_C to + 50_C, 90 to 95% RH
–55_C to + 75_C, 90 to 95% RH
ECCompliance There are no current European Directives that apply to this product.
PollutionDegree 2 Do not operate in environments where conductive pollutants may be present.

AMT75 Impedance Adapter
AMT75 Impedance Adapter Instructions 7
1.100
1.090
1.080
1.070
1.060
1.050
1.040
1.030
1.020
1.010
1.000
VSWR
Frequency (MHz)
1.0 10 100 1000
0
10
20
30
40
50
Return
loss(dB)
Figure 3: Typical VSWR and return loss

8AMT75 Impedance Adapter Instructions
Performance Verification
Use the following procedures to verify the warranted specifications of the
AMT75 adapter. Before beginning these procedures, photocopy the test record
on page 13 and use it to record the performance test results for your AMT75
adapter. The recommended calibration interval is one year.
These procedures are for use by qualified service personnel only.
Test Equipment
Table 1 itemizes the equipment required, provides an example or part number of
the equipment, and explains the purpose of the equipment.
Table 1: Test equipment
Description Minimumrequirements Example product
Power supply (1) 1 VDC out across 75 Wwith
< 0.5 mV resolution Wavetek 9100
Digitalmultimeter (1) 5 1/2 digit with sense, W4 wire,
50 Wand 75 W±0.1%,
DCV: 1 V and 200 mV ±0.1%
Kiethley2000
Fluke884X
75 Wterminator (1) 75 W±0.1%, 3 VRMS, BNC 011-0103-02
50 Wterminator (1) 50 W±0.1%, 2W, BNC 011-0123-00
BNC banana adapter (3) BNC female to dual banana plug 103-0090-00
BNC male connector (1) 1 male to 1 male 103-0029-00
50 WBNC cable (2) 2 foot BNC male 012-1342-00
50 WBNC “T” adapter (3) 2 female to 1 male BNC 103-0030-00
75 WBNC cable (3) 2 foot BNC male 012-1339-00
75 WBNC “T” adapter (2) 2 female to 1 male PasternackModel# PE9365
50 WBNC adapter (1) 1 female to 1 female 103-0028-00

Performance Verification
AMT75 Impedance Adapter Instructions 9
Output Impedance
1. Set up the DMM as follows:
DMM Setting
Mode 4 Wire
Range 100 
2. Connect the AMT75 adapter as shown in Figure 4.
NOTE. Connect the input and sense of the DMM to the output of the AMT75
adapter with a 50 WBNC T adapter, two 50 WBNC cables, and two BNC
banana adapters.
50.000 
Multimeter
75 terminator
50 BNC cables,
50 T adapter,
and 50 BNC adapter
Figure 4: Test setup for output impedance
3. Check that the DMM reads 50 W$1.5% (49.25 to 50.75).
4. Disconnect 50 WBNC T adapter, AMT75 adapter, and 75 Wterminator from
the setup.

Performance Verification
10 AMT75 Impedance Adapter Instructions
Input Impedance
1. Connect the AMT75 adapter as shown in Figure 5.
CAUTION. To avoid damaging the 75 Winput, use only 75 Wconnectors and
75 Wcables on the 75 Winput.
75.000 W
Multimeter
75 WBNC cables
and 75 WT adapter
50 WBNC adapter
50 Wtermination
Figure 5: Test setup for input impedance
2. Check that the DMM reads 75 W$1.5% (73.875 to 76.125).
3. Disconnect setup.

Performance Verification
AMT75 Impedance Adapter Instructions 11
Attenuation Accuracy
1. Set up the equipment as follows:
DMM Setting
Mode DCV
Range 10 V
Power Supply Setting
DCV 1.000 V
2. Connect the equipment as shown in Figure 6.
CAUTION. To avoid damaging the 75 Winput, use only 75 Wconnectors and
75 Wcables on the 75 Winput.
+–
Multimeter
Power supply
+1.0000 V
50 Wtermination
50 WBNC adapter
75 WBNC cables and 75 WT adapters
Figure 6: Measuring the power supply output voltage
3. Activate the power supply and adjust the output until the DMM reads
1.000 V.
4. Deactivate the power supply but do not change the output setting.
5. Connect the equipment as shown in Figure 7.

Performance Verification
12 AMT75 Impedance Adapter Instructions
+–
Multimeter +0.2000 V
50 termination and cable
Power supply
50 BNC adapter
75 BNC cables and 75 T adapter
Figure 7: Measuring the attenuation accuracy
6. Change the DMM range as follows:
DMM Setting
Range 1 V
7. Activate the power supply.
8. Check that the voltage is attenuated by 5X $1.5% (the DMM reads 0.197
to 0.203).
9. Deactivate the power supply and disconnect the test setup.

Performance Verification
AMT75 Impedance Adapter Instructions 13
AMT75 Test Record
Photocopy this page and use it to record the performance test results for your
AMT75 adapter.
AMT75 Test Record
Instrument Serial Number: Certificate Number:
Temperature: RH %:
Dateof Calibration: Technician:
AMT75 Performance Test Minimum Incoming Outgoing Maximum
Output Impedance: 50 ±1.5% 49.25 __________ __________ 50.75
Input impedance: 75 ±1.5% 73.875 __________ __________ 76.125
Attenuation accuracy: 5X (–14 dB) ±1.5%
(measured with 2.500 V on the input)
Inputvoltage
Outputvoltage
Input Boutput = attenuation factor
N/A
0.197
4.925
1.000
B__________
= __________
1.000
B__________
= __________
N/A
0.203
5.075

14 AMT75 Impedance Adapter Instructions
Replaceable Parts
1
2
3
4
NOTE: Parts illustrated
with dashed lines are not
replaceable
5
Figure 8: Replaceable parts

Performance Verification
AMT75 Impedance Adapter Instructions 15
1
2
3
4
5
Figure 9: Optional accessories