Agilent Technologies 8494G Service manual

Agilent Technologies
8494/95/96G/H Attenuators
Operating and Service
Manual
Agilent Part Number: 08495-90025
Printed in USA
Print Date: August 2004
Supersedes: July 2002

ii 8494/95/96G/H Operating And Service Manual
Notice
The information contained in this document is subject to change without
notice.
Agilent Technologies makes no warranty of any kind with regard to this
material, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Agilent Technologies
shall not be liable for errors contained herein or for incidental or
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use of this material.
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its software on equipment that is not furnished by Agilent Technologies.
This document contains proprietary information which is protected by
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written consent of Agilent Technologies.
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Data and Computer Software clause at DFARS 252.227-7013 for DOD
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Agilent Technologies, Inc.
1400 Fountaingrove Parkway
Santa Rosa, CA 95403-1799, U.S.A.
© Copyright 2000–2002, 2004 Agilent Technologies, Inc.

8494/95/96G/H Operating And Service Manual iii
What You’ll Find in This Manual…
•Overview, page 1
•Specifications, page 6
•Installation, page 10
•Operating Instructions, page 12
•Replaceable Parts, page 15
•Service, page 16

iv 8494/95/96G/H Operating And Service Manual
Warranty
Custom systems are warranted by contractual agreement between Agilent
Technologies and the customer.
Certification Agilent Technologies, Inc., certifies that this product met its published
specifications at the time of shipment from the factory. Agilent Technologies
further certifies that its calibration measurements are traceable to the
United States National Institute of Standards and Technology (NIST,
formerly NBS), to the extent allowed by the Institute’s calibration facility,
and to the calibration facilities of other International Standards
Organization members.
Documentation
Warranty THE MATERIAL CONTAINED IN THIS DOCUMENT IS
PROVIDED "AS IS," AND IS SUBJECT TO BEING CHANGED,
WITHOUT NOTICE, IN FUTURE EDITIONS. FURTHER, TO
THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW,
AGILENT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS
OR IMPLIED WITH REGARD TO THIS MANUAL AND ANY
INFORMATION CONTAINED HEREIN, INCLUDING BUT NOT
LIMITED TO THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. AGILENT SHALL NOT BE LIABLE FOR ERRORS
OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN
CONNECTION WITH THE FURNISHING, USE, OR
PERFORMANCE OF THIS DOCUMENT OR ANY
INFORMATION CONTAINED HEREIN. SHOULD AGILENT
AND THE USER HAVE A SEPARATE WRITTEN AGREEMENT
WITH WARRANTY TERMS COVERING THE MATERIAL IN
THIS DOCUMENT THAT CONFLICT WITH THESE TERMS,
THE WARRANTY TERMS IN THE SEPARATE AGREEMENT
WILL CONTROL.

8494/95/96G/H Operating And Service Manual v
Service and Support
Product maintenance agreements and other customer assistance agreements
are available for Agilent Technologies products. Any adjustment,
maintenance, or repair of this product must be performed by qualified
personnel. Contact your customer engineer through your local Agilent
Technologies Service Center. You can find a list of local service
representatives on the Web at:
http://www.agilent.com/find/assist
Click on “Contact Us” and select your country.
Safety and Regulatory Information
Review this product and related documentation to familiarize yourself with
safety markings and instructions before you operate the instrument. This
product has been designed and tested in accordance with international
standards.
WARNING The WARNING notice denotes a hazard. It calls attention to a procedure,
practice, or the like, that, if not correctly performed or adhered to, could result
in personal injury. Do not proceed beyond a WARNING notice until the
indicated conditions are fully understood and met.
CAUTION The CAUTION notice denotes a hazard. It calls attention to an operating
procedure, practice, or the like, which, if not correctly performed or adhered
to, could result in damage to the product or loss of important data. Do not
proceed beyond a CAUTION notice until the indicated conditions are fully
understood and met.

vi 8494/95/96G/H Operating And Service Manual
Instrument Markings
Safety Earth
Ground This is a Safety Class I product (provided with a protective earthing
terminal). An uninterruptible safety earth ground must be provided from the
main power source to the product input wiring terminals, power cord, or
supplied power cord set. Whenever it is likely that the protection has been
impaired, the product must be made inoperative and secured against any
unintended operation.
Before Applying
Power Verify that the product is configured to match the available main power
source as described in the input power configuration instructions in this
manual. If this product is to be powered by autotransformer, make sure the
common terminal is connected to the neutral (grounded) side of the ac power
supply.
When you see this symbol on your instrument, you should refer to the instrument’s
instruction manual for important information.
This symbol indicates hazardous voltages.
The laser radiation symbol is marked on products that have a laser output.
This symbol indicates that the instrument requires alternating current (ac) input.
The CE mark is a registered trademark of the European Community. If it is
accompanied by a year, it indicates the year the design was proven.
The CSA mark is a registered trademark of the Canadian Standards Association.
1SM1-A This text indicates that the instrument is an Industrial Scientific and Medical Group 1
Class A product (CISPER 11, Clause 4).
This ISM device complies with Canadian ICES-001.
Cet appareil ISM est conforme a la norme NMB du Canada.
This symbol indicates that the power line switch is ON.
This symbol indicates that the power line switch is OFF or in STANDBY position.
!

8494/95/96G/H Operating And Service Manual 1
Overview
This manual contains operating instructions for the Agilent 8494G/H,
8495G/H, and 8496G/H attenuators. Included in the manual is information
required to install and test these attenuators.
Specification Instrument specifications are indicated in Specifications, page 6. These
specifications are the performance standards or limits against which the
instruments may be tested.
Instruments Covered by
Manual The instruments covered by this manual have a two-part serial number. The
first four digits and letter comprise the serial number prefix. The last five
digits form the sequential suffix that is unique to each instrument. The
contents of this manual apply to instruments with serial prefixes 2544A and
above.
An instrument manufactured after the printing of this manual may have a
serial prefix that is not listed above. This unlisted serial prefix indicates that
the instrument is different from those documented in this manual.
Description The 8494G/H, 8495G/H, and 8496G/H are 50-ohm coaxial programmable
step-attenuators. Each attenuator is composed of three or four attenuator
sections connected in cascade. Each section consists of a precision, thin-film
attenuator card, a lossless thru-line, and a ganged pair of solenoid-actuated
slab line transmission lines. The slab lines are flexed by the solenoid
plungers to make contact with either the attenuator card or the thru-line. The
slab line contacts are gold plated leaf springs which ensure long life and
extremely high repeatability.

28494/95/96G/H Operating And Service Manual
Overview
Figure 1 Typical Four Section Attenuator Schematic Diagram
Table 1 and Table 2 on page 3 and Table 3 on page 4 show the typical
switching arrangement to increase the amount of attenuation in an 8494G/H,
8495G/H, or 8496G/H in a linear manner. To ensure specified performance,
it is recommended that the attenuator sections that are shown in the
following tables be used. With the attenuator programmed for 0 dB
attenuation, the resultant attenuation is the insertion loss (residual
attenuation). The 8494G/H has a minimum selectable step of 1 dB, while the
8495G/H and 8496G/H have a minimum selectable step of 10 dB. The
accuracy of the attenuators is within the limits given in Specifications,
page 6.
•The 8494G/H are four-section attenuators with a maximum attenuation
of 11 dB.
•The 8495G/H are three-section attenuators with a maximum attenuation
of 70 dB.
•The 8496G/H are four-section attenuators with a maximum attenuation
of 110 dB.
NOTE
Solenoid (K4) and
associated circuitry
are not available in
models 8495G and
8495H.

8494/95/96G/H Operating And Service Manual 3
Overview
Table 2 8495G/H Attenuator Switching Order
Table 1 8494G/H Attenuator Switching Order
8494G/H
Attenuator Sections
Atten
(dB) 1 1 dB 2 2 dB 3 4 dB 4 4 dB
0
1X
2X
3XX
4X
5X X
6XX
7XXX
8XX
9X XX
10 XXX
11XXXX
8495G/H
Attenuator Sections
Atten
(dB) 1 10 dB 2 20 dB 3 40 dB
0
10 X
20 X
30 X X
40 X
50 X X
60 X X
70XXX

48494/95/96G/H Operating And Service Manual
Overview
Table 3 8496G/H Attenuator Switching Order
Each solenoid requires a drive of 20 to 30 V with a switching current of
approximately 125 mA*at 24 V dc per section. The solenoid switching time
is less than 20 milliseconds including settling time. Once switched, the
solenoid plungers are held in place by permanent magnets and the solenoid
plungers automatically disconnect the selected coil drive and connect the
opposite coil drive (see Figure 1 and Figure 2). This simplifies the coil driver
circuit design and reduces the amount of heat dissipated by the solenoid
coils since the solenoid coils are energized only for the 20 milliseconds
switching time.
8496G/H
Attenuator Sections
Atten
(dB) 1 10 dB 2 20 dB 3 40 dB 4 40 dB
0
10 X
20 X
30 X X
40 X
50 X X
60 X X
70XXX
80 X X
90 X X X
100 X X X
110XXXX
* For serial number prefixes below 1722A, change 125 mA to 110 mA.

8494/95/96G/H Operating And Service Manual 5
Overview
Figure 2 Typical Solenoid Coil Driver Circuits
CAUTION Do not exceed the RF power rating of 1 W average or 100 W peak with a
maximum pulse width of 10 µs. Do not connect an attenuator RF input or
output connector to greater the ±7 Vdc. If the attenuator must be connected
to a device with a potential greater than ±7 Vdc, use a blocking capacitor.
Instrument Options Each instrument is specified with an option number which denotes the
configuration of the input and output connectors.
Option Connector Description
001 Both connectors type-N female
002 Both connectors SMA female
0031
1. Option 003 is not available on the 8495G.
Both connectors 7 mm

68494/95/96G/H Operating And Service Manual
Specifications
Specifications
Frequency Range
and Attenuation
Attenuation Accuracy (±dB): (Referenced from 0 dB)
Instrument Frequency Range Attenuation
8494G dc to 4 GHz 0 dB to 11 dB in 1 dB steps
8494H dc to 18 GHz 0 dB to 11 dB in 1 dB steps
8495G dc to 4 GHz 0 dB to 70 dB in 10 dB steps
8495H dc to 18 GHz 0 dB to 70 dB in 10 dB steps
8496G dc to 4 GHz 0 dB to 110 dB in 10 dB steps
8496H dc to 18 GHz 0 dB to 110 dB in 10 dB steps
8494G/H 8495G/H
8496G/H 8494G 8494H 8495G 8495H 8496G 8496H
AttenuationSelection
(dB) dc–4 GHz dc–12.4 GHz 12.4–18 GHz dc–4 GHz dc–12.4 GHz 12.4–18 GHz dc–4 GHz dc–12.4 GHz 12.4–18 GHz
1 10 0.2 0.3 0.7 0.2 0.5 0.6 0.2 0.5 0.6
2 20 0.2 0.3 0.7 0.4 0.7 0.8 0.4 0.7 0.8
3 30 0.3 0.4 0.7 0.5 0.9 1.2 0.5 0.9 1.2
4 40 0.3 0.4 0.7 0.7 1.2 1.6 0.7 1.2 1.6
5 50 0.3 0.5 0.7 0.8 1.5 2.0 0.8 1.5 2.0
6 60 0.3 0.5 0.8 1.0 1.8 2.4 1.0 1.8 2.4
7 70 0.4 0.6 0.8 1.2 2.1 2.8 1.2 2.1 2.8
8 80 0.4 0.6 0.8 - - - 1.3 2.4 3.2
9 90 0.4 0.6 0.8 - - - 1.5 2.7 3.6
10 100 0.4 0.6 0.9 - - - 1.6 3.0 4.0
11 110 0.5 0.7 0.9 - - - 1.8 3.3 4.4

8494/95/96G/H Operating And Service Manual 7
Specifications
Maximum SWR
Maximum Residual
Attenuation
Attenuation Repeatability ±0.01 dB typical after 5 million cycles
RF Power Handling
Capability 1 W average, 100 W peak with maximum pulse width of 10 microseconds
(all models)
Solenoid Drive
Instrument Frequency Range (GHz) Maximum SWR
8495G dc to 4 1.35
8495H dc to 8
8 to 12.4
12.4 to 18
1.35
1.5
1.7
8494G,
8496G dc to 4 1.5
8494H,
8496H dc to 8 8 to 12.4
12.4 to 18
1.5
1.6
1.9
Instrument Maximum Residual Attenuation
8494G,
8494H 0.6 dB + 0.09 dB/GHz
8495G,
8495H 0.4 dB + 0.07 dB/GHz
8496G,
8496H 0.6 d8 + 0.09 dB/GHz
Solenoids Drive Coil Voltage Switching Current
All models
(approximately) 20 to 30 Vdc 125 mA1at 24V
(190Ω, 65mH)
1. For serial number prefixes below 1722S, change 125mA to 110mA.

88494/95/96G/H Operating And Service Manual
Specifications
Solenoid Cable Connector Refer also to Figure 3.
Figure 3 Solenoid Cable Pin Configuration
Section Section 1 Section 2 Section 3 Section 4 Power
Solenoid Coil Thru-Line Atten
Card Thru-Line Atten Card Thru-Line Atten Card Thru-Line Atten Card V+
Cable Wire Color
Code1PUR YEL BLK GRN ORN BLU BRN WHT RED
Connector Plug
Pin Number 2567891011121
8494G/H 0dB 1dB 0dB 2dB 0dB 4dB 0dB 4dB –
8495G/H 0dB 10dB 0dB 20dB 0dB 40dB – – –
8496G/H 0dB 10dB 0dB 20dB 0dB 40dB 0dB 40dB –
Option 016
Flat Pack
Plug Pin Number3
132115394106
1. Five-foot cable and mating plug assembly provided.
2. Pin 1 Common solenoid drive (+24 Vdc).
3. Pin 6 is common for all coils. Pins 1, 7, 8, 12 and 14 are not used.

8494/95/96G/H Operating And Service Manual 9
Specifications
Minimum Life >5 million cycles per section
Switching speed Maximum 20 milliseconds including settling time.
Environment Limits The instrument should be stored in a clean, dry environment. The following
environmental limits apply to storage and shipment, and operation.
Physical Characteristics
Characteristic Storage and Shipping Value Operating Value
Temperature –40 to +75 °C 0 to +55 °C
Humidity < 95% relative < 95% relative
Altitude < 7600 m (25000 ft) < 4600 m (15000 ft)
Instrument Dimensions 1
(depth x width x height)
1. Dimensions are for general information only. If dimensions are required for building special
enclosures, contact your Agilent field engineer.
Weight 2
2. Weight and width of the instrument varies with the option selected due to the type of connectors.
8494G/H
8496G/H 6.25 in x 2.875 in x 1.6875 in 159 mm x 73 mm x 43 mm 16 oz
454 g
8495G/H 5.125 in x 2.875 in x 1.6875 in
130 mm x 73 mm x 43 mm 12 oz
340 g

10 8494/95/96G/H Operating And Service Manual
Installation
Installation
Initial Inspection Inspect the shipping container for damage. If the shipping container or
cushioning material is damaged, it should be kept until the contents of the
shipment have been checked for completeness and the instrument has been
checked mechanically and electrically. A procedure for checking electrical
performance is given under “Operator’s Check” on page 12 (also see
“Performance Tests” on page 14). If the contents of the shipment are
incomplete, if there is mechanical damage or defect, or if the instrument
does not pass the electrical performance test, notify the nearest Agilent
Technologies office. If the shipping container is damaged, or the cushioning
material shows signs of stress, notify the carrier as well as the Agilent office.
Keep the shipping materials for the carrier's inspection. The office will
arrange for repair or replacement without waiting for claim settlement.
NOTE Containers and materials identical to those used in factory packaging are
available through Agilent Technologies offices. If the instrument is being
returned to Agilent for servicing, attach a tag indicating the type of service
required, return address, model number, and full serial number. Also, mark
the container FRAGILE to assure careful handling. In any correspondence,
refer to the instrument by model number and full serial number.
Mating Connectors Mating RF connectors used with the Option 001 must be type-N male
connectors, which comply with U.S. military standard MIL-C-39012 (See
Figure 7 on page 19). For Option 002, male SMA connectors must be used.
For Option 003, 7 mm mating connectors must be used (Figure 6 on page
18).
The solenoid drive cable connector plug is a Viking Industries, Inc., part
number TKP12-102-P-TS-100-AU (see Replaceable parts). The connector
plug and contacts without the cable can be ordered from a Viking distributor.
When ordering the complete cable assembly from Agilent, use the part
number listed in Table 5, “Replaceable Parts,” on page 15.
CAUTION When installing the instrument, make sure that the connectors do not support
weight or bear torque. The preferred procedure is to set up all equipment in
position before connecting the instrument.

8494/95/96G/H Operating And Service Manual 11
Installation
Installation
Instructions The attenuators may be installed with or without the base. The base is
removed by unscrewing the two fillister head screws from the bottom of the
base. The attenuator may be mounted without the base by inserting two 4-40
screws into the screw holes in the bottom of the attenuator. Removing the
base and mounting the attenuator does not affect the performance of the
attenuator.
The solenoid drive cable connector plug is connected to the attenuator by
aligning the plug (Pl) with the jack (Jl) on the attenuator, and then pushing
the plug over the jack. The plug is removed by grasping the ribbed sides of
the plug and squeezing them together while pulling back until the plug clears
the jack.

12 8494/95/96G/H Operating And Service Manual
Operating Instructions
Operating Instructions
CAUTION Do not apply RF power greater than 1 W average, or 100 W peak with a
maximum pulse width of 10 microseconds. If these limits are exceeded, the
attenuators may be damaged.
CAUTION Do not ground both solenoid drive pins at the same time. This causes rapid
cycling of the solenoid and could reduce the operating life of the attenuator.
The rapid cycling may produce a buzzing sound from the attenuator.
Either RF connector may be used as the input or output connector. Connect
the solenoid drive cable to the solenoid driveconnector (J1). By applying the
proper voltage and grounds to the proper pins of J1, the attenuator will either
increase or decrease the amount of attenuation as selected.
Operator’s Check The Operator's Check is supplied to allow the operator to make a quick
check of the instrument prior to use or if a failure is suspected.
Description The attenuator is driven from a 50-ohm signal source at 1 kHz. The output
level from the attenuator is detected by a narrow-bandwidth voltmeter. The
attenuator and detector range switches are stepped together and the
variations in level noted. This verifies that each attenuator section is being
properly switched and checks the low-frequency accuracy of the attenuator.
NOTE The SWR meter used in this check is calibrated for a square-law detector and
therefore the range changes and errors (read in dB) are twice that indicated
by the meter.
Figure 4 Operator’s Check Setup

8494/95/96G/H Operating And Service Manual 13
Operating Instructions
Procedure 1. Connect equipment as shown in Figure 4 on page 12 with the attenuator
set to 0 dB attenuation.
2. Set the test oscillator to 0.3 Vrms at 1 kHz.
3. Set SWR meter range to 2 dB (expanded) [or for the 8494G/H to 10 dB
(expanded)] and adjust its bandwidth to center of adjustment range. Fine
tune oscillator frequency to obtain maximum meter indication.
4. Set attenuator and SWR meter range switch as listed in Table 4 and
verify that SWR meter indicates within limits shown.
Table 4 Attenuator and SWR Settings
SWR Meter Range
(dB) Attenuation (dB) Meter Indication (dB)
Minimum Actual Maximum
8494G/H 8495G/H
8496G/H 8494G/H 8495G/H 8496G/H 8494G/H 8495G/H 8496G/H 8494G/H 8495G/H 8496G/H 8494G/H 8495G/H 8496G/H
10 2 0 0 0 - - Setto0.0 Set to 0.5 - -
10 6 1 10 10 0.40 1.40 - - 0.60 1.60
10 12 2 20 20 0.90 0.30 - - 1.10 0.70
10 16 3 30 30 1.35 1.25 - - 1.65 1.75
10122 4 40 40 1.85 0.15 - - 2.15 0.85
12 26 5 50 50 0.35 1.10 - - 0.65 1.90
12 32 6 60 60 0.85 0.00 - - 1.15 1.00
12 36 1
1. Adjust range by 2 dB, if needed, to obtain a on-scale indication.
7 70 70 1.30 0.90 - - 1.70 2.10
1214218 - 80 1.80 –0.15 - - 2.20 1.15
14 46 19 - 90 0.30 0.75 - - 0.70 2.25
14 52 1 10 - 100 0.80 –0.30 - - 1.20 1.30
14 56 111 - 110 1.75 0.60 - - 1.75 2.40

14 8494/95/96G/H Operating And Service Manual
Operating Instructions
Performance Tests The instrument can be tested to the accuracy of the “Specifications” on
page 6, with an automatic network analyzer or equivalent equipment of
suitable accuracy. If an automatic network analyzer is available, test the
instrument using the procedures in the analyzer's operating manual.
Refer to the Agilent 11713A Attenuator/Switch Driver Operating and
Service Manual for programming instructions.
Adjustments The attenuators have no internal adjustments and should not be opened. If
defective, return the attenuator to the nearest Agilent Technologies office for
repair.