Title & Document Type: 11848A Phase Noise Interface Service Manual
Manual Part Number: 11848-90004
Revision Date: June 1990
HP References in this Manual
This manual may contain references to HP or Hewlett-Packard. Please note that HewlettPackard's former test and measurement, semiconductor products and chemical analysis
businesses are now part of Agilent Technologies. We have made no changes to this
manual copy. The HP XXXX referred to in this document is now the Agilent XXXX.
For example, model number HP8648A is now model number Agilent 8648A.
About this Manual
We’ve added this manual to the Agilent website in an effort to help you support your
product. This manual provides the best information we could find. It may be incomplete
or contain dated information, and the scan quality may not be ideal. If we find a better
copy in the future, we will add it to the Agilent website.
Support for Your Product
Agilent no longer sells or supports this product. You will find any other available
product information on the Agilent Test & Measurement website:
www.tm.agilent.com
Search for the model number of this product, and the resulting product page will guide
you to any available information. Our service centers may be able to perform calibration
if no repair parts are needed, but no other support from Agilent is available.
A4TP202 1251-0600 0 CONNECTOR-SOL CONT PIN 1.14-MM-BSC-SZ SO
A4TP203 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP204 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP205 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP206 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP207 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP208 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP209 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP210 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP211 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP212 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP213 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP214 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP215 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP216 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4TP217-219 NOT ASSIGNED
A4TP220 1251-0600 0 CONNECTOR-SQL CONT PIN 1.14-MM-BSC-SZ SO
A4U1 0960-0640 0 1
A4U2 NOT ASSIGNED
A4U3 18264412 1 3 IC COMPARATOR PRCN DUAL 8-CHP-P PKG
A4U4 1826-0783 9 IC OP AMP LOW-NOISE 8-OIP-C PKQ
A4U5 1826-0783 9 IC OP AMP LOW-NOISE 8-OIP-C PKQ
A4U6 1820-1201 8 IC GATE TTL LS AND QUAD 2-INP
A4U7 18584047 5 2 TRANSISTOR ARRAY 16-PIN PLSTC DIP
A4U8 1858-0047 6 TRANSISTOR ARRAY 16-PIN PLSTC DIP
A4U9 6081-2040 9 1 BURNIN1826-0035
A4U10-200 NOT ASSIGNED
A4U201 1826-0188 8 O/A
A4U202 1820-1547 3 3 IC MULTIPLXR 8-CHAN-ANLQ16-OIP-C PKQ
A4U203 1820-1547 3 K MULTIPLXR 8-CHAN-ANLQ 16-OIP-C PKQ
A4U204 1820-1547 3 IC MULTIPLXR 8-CHAN-ANLQ 16-OIP-C PKQ
A4U205 18264606 5 IC SWITCH ANLQ QUAD 16-DIP-C PKQ
A4U206 18264606 5 IC SWITCH ANLQ QUAD 16-OIP-C PKQ
A4U207 18264606 5 IC SWITCH ANLQ QUAD 16-DIP-C PKQ
A4U208 1820-1199 1 IC INV TTL LS HEX 1-INP
A4U209 1820-1189 1 IC INV TTL LS HEX 1-INP
A4U210 1820-1199 .1 IC INV TTL LS HEX 1-INP
A4U211 1820-1112 8 1 IC FF TTL LS
A4U212 16264785 1 IC OP AMP LOW-BIAS-H-IMPD DUAL 8-DIP-C
A4U213 18264783 9 IC OP AMP LOW-NOISE 8-DIP-C PKQ
A4U214 16264783 9 IC OP AMP LOW-NOISE 8-DIP-C PKQ
A4U215 18264753 3 2 IC OP AMP LOW-BIAS-H-IMPD QUAD 14-OIP-C
A4U216 18264759 9 1 IC COMPARATOR QP QUAD 14-OIP-C PKQ
A4U217 18264606 5 IC SWITCH ANLQ QUAD 16-DIP-C PKQ
A4U218 18264753 3 IC OP AMP LOW-BIAS-H-IMPD QUAD 14-OIP-C
A4U219 18264716 8 IC OP AMP LOW-NOISE DUAL 8-DIP-C PKQ
EAST 24001 MISSION AVENUE, TAF C-34, SPOKANE, WASHINGTON,
Service Manual HP Part 11848-90004
Microfiche Service Manual HP Part 11848-90011 Printed in
U.S.A.
fnm
99220
HEWLETT
EM PACKARD
U.S.A.
: MAY 1990
Model 11848A Option 301
ACCESSORIES SUPPLIED
The accessories supplied are pieces of equipment that are shipped with every Interface. The
accessories are shown in Figure 1.
Line Power Cable. The line power cable may be supplied in several plug configurations, depending
on the destination of the original shipment. Refer to Power Cables in the Installation section of this
Service manual.
General Information
Fuses.
Vac (HP part number 2110-0012) are supplied. One fuse is factory installed according to the voltage
available in the country of original destination. Refer to Power Requirements in the Installation of
this Service manual.
Fuses with a
HP 3048A Option 301 Software and Manual Set. The HP 3048A software and associated manuals
are shipped with the Interface.
HP 3048A Software (HP part number 03048-10015).
HP 11848A Service Manual (HP part number 11848-90004).
HP 3048A Option 301 Installation Guide (HP part number 03048-90043).
HP 3048A Option 301 Operating Manual (HP part number 03048-90042).
HP 3048A Option 301 System Calibration Manual (HP part number 03048-90041).
HP 3048A Option 301 Reference Manual (HP part number 03048-90040).
50Q Termination. This 50O load is used to terminate the Interface's Spectrum Analyzer output if
no RF spectrum analyzer is available (HP part number 1250-0207).
Adapters, Type-N to BNC. Three adapters are provided for system operation (HP part number
1250-0780).
Cable Assemblies: BNC. Two 30 cm (12 in.) cables are provided for system operation (HP part
number 8120-1838).
0.75A
rating for
115 Vac
(HP part number 2110-0063) and a 0.5A rating for 230
Noise Floor Test Fixture. This test fixture is used to run performance tests (HP part number
11848-61032).
Cable Assembly: BNC to SMB. This cable assembly can be used during troubleshooting (HP part
number 08954-60105).
rev.WJANQl
General Information
RECOMMENDED TEST EQUIPMENT
Table 1 lists the test equipment and accessories recommended for use in testing, adjusting, and
servicing the Interface. If any of the recommended equipment is unavailable, instruments with
equivalent minimum specifications may be substituted.
Tests for the Interface are performed during the HP 3048A Performance Tests which are available
in the HP 3048A Option 301 System Calibration Manual in Performance Tests.
Table 1. Recommended Test Equipment
Model 11848A Option 301
Dynamic Signal Analyzer
Counter (550 MHz)
Function Generator
Oscilloscope
Power Meter and Sensor
*
"" The HP 3561A is included with the HP 3048A system.
OPTIONS AVAILABLE
Options are variations on the standard instrument which can be ordered during the purchase.
Electrical Options
Option 201: Add High Frequency Phase Detector. This option adds a 1.2 to 18 GHz phase
detector to the Interface. This phase detector extends the range of carrier frequencies that can
be demodulated within the Interface without external down conversion by the System. All of the
HP 3048A specifications from 1.6 to 18 GHz carrier frequency are valid with this option.
Instrument Type
A =
Adjustments, C = Functional Checks, P = Performance Tests,
Model Number
HP 3561A
HP 5383A, HP 5386A
HP 3312A, HP 3325A
HP 1740 A
HP435BorHP436Awith
HP8481AorHP8482A
Use*
A.C.P.T**
P
P.T
T
T
T =
Troubleshooting
Mechanical Options
Option 907: Front-Handle Kit. Front handles are provided when Option 907 is ordered. After
shipment, you can order a Front-Handle Kit as HP part number 5061-9689.
Option 908: Rack-Flange Kit. Rack flanges are provided for the HP 11848A Phase Noise Interface
when Option 908 is ordered. After shipment, you can order a Rack-Flange Kit as HP part number
5061-9677.
Option 909: Rack-Flange and Front-Handle Combination Kit. This is not a Front-Handle Kit and
a Rack-Flange Kit packaged together; it is a unique part that combines both functions. Combination
kits are provided for the HP 11848A Phase Noise Interface when Option 909 is ordered. After
shipment, you can order a Rack-Flange and Front-Handle Combination Kit as HP part number
5061-9683.
22.6
Model
11848 A
Table
5.
Replaceable Parts
Replaceable Parts
Reference
Designation
A3J1-11
A
A3J12
A3J13
A3JH
A3J15
A3J16
A3J201
A3J202
A3J203
A3J204
A3L1
A3L2-200
A3L201
A3L202
A3L203
A3L204
A3L205
A3L206
A3L207
A3L208
A3L209
A3L210
A3L211
A3L212
A3L213
A3L214
A3L215
A3L216
A3L217
A3L218
A3L219
A3L220
a
A3MP1
A3MP2
A3MP3
A3Q1
A302
A3Q3
A3Q4
A3Q5-200
A3Q201
A3R1
A3R2
A3R3
A3R4
A3R5
A3R6
A3R7
A3R8
A3R9
A3R10
A3R11-14
A3R15
A3R16
A3R17
A3R18
HP
Part
Number
1260-1255
1250-1255
1250-1255
1205-0095
1251-4670
1251-7264
1251-3825
1251-8472
9100-1661
9100-3560
9100-3560
9100-3560
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0137
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0210
9140-0137
1251-1998
1390-0457
1390-0458
1855-0410
1855-0410
1855-0410
1855-0276
0757-0280
0698-3157
0698-3157
0698-3157
0698-3157
0698-3157
0698-3460
0698-3454
0757-0444
0698-3157
0698-3157
0698-3450
c
D
1
1
1
0
2
6
7
0
4
6
Qty
14
CONNECTOR-RF SMB M PC 50 OHM
NOT ASSIGNED
14
CONNECTOR-RF SMB M PC 50 OHM
14
CONNECTOR-RF SMB M PC 50 OHM
1
HEAT SINK SGL TO-5/TO-39-CS
NOT ASSIGNED
CONNECTOR 3-PIN M POST TYPE
CONN-POST TYPE .100-PIN-SPCG 34-CONT
NOT ASSIGNED
CONNECTOR 5-PIN M POST TYPE
TRANSISTOR PNP SI PD - 625MW FT « 200MHZ
TRANSISTOR NPN SI PD - 625MW FT = 200MHZ
TRANSISTOR NPN SI TO-39 PD= 1W FT = 800MHZ
TRANSISTOR PNP 2N2905A SI TO-39 PD= 600MW
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
CAPACITOR-FXD 1UF+-20% 50VDC TA
COAX CABLE ASSEMBLY F BNC-SMB
A3J5 TO REAR PANEL J17 (5)
COAX CABLE ASSEMBLY F BNC-SMB
A3J6 TO REAR PANEL J14 (7)
COAX CABLE ASSEMBLY F BNC-SMB
A3J7 TO FRONT PANEL J1 (80)
WASHER SHOULDER
COAX CABLE ASSEMBLY F BNC-SMB
A3J8 TO FRONT PANEL J11 (87)
COAX CABLE ASSEMBLY F BNC-SMB
A6J2 TO FRONT PANEL J7 (85)
COAX CABLE ASSEMBLY F SMB-SMB
A3J10TOA4J206(2)
COAX CABLE ASSEMBLY F BNC-SMB
A8J2 TO FRONT PANEL J8 (86)
NOT ASSIGNED
COAX CABLE ASSEMBLY F BNC-SMB
A6J3 TO REAR PANEL J15 (6)
COAX CABLE ASSEMBLY F BNC-SMB
A7J2 TO FRONT PANEL J9 (81)
COAX CABLE ASSEMBLY F BNC-SMB
A8J2 TO FRONT PANEL J10 (83)
COAX CABLE ASSEMBLY F SMB-SMB
A3J9 TO A7J3 (82)
COAX CABLE ASSEMBLY F BNC-SMB
A4J9 TO REAR PANEL J18 (84)
COAX CABLE ASSEMBLY F BNC-SMB
A4J2 TO FRONT PANEL J13 (96)
COAX CABLE ASSEMBLY F BNC-SMB
A4J16 TO FRONT PANEL J12 (97)
S.B-SMB
Mfr.
Code
28480 08660-60056
28480 11848-61006
28480 86601-60036
28480 86601-60069
28480 11848-61007
28480 11848-61008
28480 11848-61009
28480 11848-61010
28480 5040-7624
28480 11848-61011
28480 11848-61012
28480 11672-60004
28480 11848-61013
28480 08954-60105
28480 11848-61014
28480 11848-61015
28480 11848-61016
28480 11848-61017
28480 11848-61018
28480 11848-61019
Mfr. Part Number
68
f Refer to Table 7 for update information. A Errata part elianfj
Model 11848 A Replaceable Parts
Table 7. Update Information for Instrument Changes
Reference
Designator
A1S1,
A1S2,
A1S3
MP2,
MP4-MP11,
MP13,
MP15
J1
Serial
Prefix
2720A
2924A
All Prefixes
Description of Change
Instruments with serial prefixes prior to 2720A have components A1S1, A1S2 and A1S3
installed.
to malfunction. Any or all of the switches may be removed without affecting the
operation of the instrument.
These switches are not loaded in instruments with serial prefixes 2720A and above.
CABINET PARTS COLOR CHANGE
Serial Prefix 2924A changes color of the instrument covers and accessories. The old
color cover and accessories are no longer available. If your instrument has serial
prefixes 2830A and below, and you must replace one of these parts, we recommend
that you order the full set of covers and accessories. See table 5.
The voltage output from the rear panelat J1 is the opposite polarity of the front panel
voltage. Silk screening has been added to the rear panel "Tune Voltage Output" which
reads:
These switches are not used, and if improperly set can cause the instrument
"Caution: Inverted Output".
Replaceable Parts Model 11848 A
C11
MP1
M1
and
hardware
attached
J1 behind
J1
J5
J7
C12and
hardware
attached
J9 behind J11
J11
11 48* PHASE NOISE INTERFACE
MP19
MP17
UNI
VOLT*C[
fh,-'
MOItf INPUT
(Opt 201 only)
MP32
f.
J4
J6 J8
(Opt
201 only)
A10 MP31
s-*ct ptjT^iis
0
0
f | W4«A PHASE hltSE MEASUREMENT B
J10
J13 J12
J14
J15 J17
72
A11J1 A11MP1
Figure
7.
Parts Identification (Front Panel View
MP30 J16
and
Rear Panel View)
J19 J18
Model 11848A Schematic Notes
Table 9. Cross Reference Index
Reference
Designator
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
Assembly Name
HP-IB Interfacing/Power Supply Assembly
LED Assembly
Analyzer Interface Assembly
Phase Detector Assembly
Not Assigned
Selected to provide optimum flatness in the X5 gain function of LNA2.
Increase the value of C17 to provide more
at the high end (40 MHz) of the amplifier output. Decrease the value
of C17 to compensate for excess roll-off at the high end. This will have
little or no effect at the low end ( <10 MHz). The input and output of
LNA2 should be isolated from the 11848A signal paths to observe the
most evident changes.
gain,
and decrease peaking,
rev.09OCT90
Schematic Notes
1.
Switches on tlhe Block Diagram are shown in
their HP-IB preset state. At Interface turn-on
with no controller connected, the power-up state
is the same as the HP-IB preset state except:
a. ATTEN 1 is set to an open-circuit
(non-programmable) state, and
b. the switches of cluster S5 through S8 are
all open.
Model 11848A
4.
Assemblies A6, A8, and A9 are controlled as
follows:
State
Control Line
A6
A8
A9
2.
The transfer function of GAIN 2 also has a
lead-lag response as follows:
33.5 kHz
6 dB
67 kHz
3. The transfer function of Lag-Lead Network 1 is
as follows:
67 kHz
26 dB
3.35 kHz
To this transfer function is added a
programmable lag-lead with the following poles
and zeros:
Lag-Lead
Number
Pole
Frequency
Zero
Frequency
Attenuation
L17
L18
L17,
L18
5. The transfer functions of Lag-Lead Network 2
on A4 and the Lag-Lead Network on A3 are
both as follows:
Off
Off
On
On
On
Off
On
Off
Off
3.35 kHz
20 dB
33.5 kHz
The passband gain of the High-Pass Filters is 2
(as measured from TP17 to the respective filter
output). The gain settings of the GAIN 3
amplifier and attenuator include the passband
gain of the High-Pass Filters.
90
0
1
2
3
4
5
6
7
4.82 Hz
8.01 Hz
9.17 Hz
9.68 Hz
9.95 Hz
9.95 Hz
9.95 Hz
9.95 Hz
9.95 Hz
40.1 Hz
115.9 Hz
306 Hz
784 Hz
1.985 kHz
5.00 kHz
12.58 kHz
6dB
14 dB
22 dB
30 dB
38 dB
46 dB
54 dB
62 dB
Block Diagram Notes
Service Model 11848A
CHANGES
All Serial Prefixes
3040A and above
On
the
A1
Component Locator:
• A1S1.S2. S3 - Delete SI, S2 and
removed. These switches are not used (open) and could cause the instrument to fail
or malfuntion if improperly set. Any or all of the switches may be removed without
affecting the operation of the instrument.
On
the
A1
Schematic:
• A1S1.S2, S3 - Delete SI, S2 and
removed. These switches are not used (open) and could cause the instrument to fail
or malfuntion if improperly set. Any or all of the switches may be removed without
affecting the operation of the instrument.
On
the Schematic:
• A11 - Use the new schematic on page 92.3 for all references to the HP-IB
Connector Assembly.
On
the Component Locator:
• A11 - Use the new component locator on page 92.4 for all references to the HP-IB
Connector Assembly.
S3.
At serial prefix 2720A, AlSl, S2 and S3 were
S3.
At serial prefix 2720A, AlSl, S2 and S3 were
rcv.09JAN9l
A1a
92.1
Model 11848 A Service
Reserved for
Future
Updates.
A1a
92.2 rcv.09JAN9l
Service Model 11848A
ji-i) MM w" « CM-I i
Jl-2>—US rrm . (pi-!)
HI
&
C12
V
Ctf
V
j|-|)
8181 rm ■ (Pl-15
Jl-*)_aUB
mm_. CP1-J7
T st
ISp
I
_QI_
ll-t) W
r
_BQ_
Sp
„_,
SB4£_
_Q1_
C)
Sp
?
If
19p
I
«M
TTT
WWW &».
-<PI-I
-<Pl-2
rev.09JAN9l
«TE
_JBUU_
All Schematic - HP-IB Assembly
Sei'ial Prefix
3(M0A
and above
-<P1-H
—<PI-5
-<Pl-»
-<Pl-7
VA
A1a
92.3
Model 11848 A
ro
JI
o m
L2
OOO
D
D
D
33
3~)
M o,
m
lUilUJ
L5
Lfc
ly yj (MCT
O
O
L7
L8
L9
y y ogo
03
_ _ o
Sg
oAogO,
TO
O
O
O
O
oeio
1
on
OifjO
corn
o.
is
A1a
92.4
rf^
P»,
O
o
Lis:
y ot^o
&&o
>ti7 Component Locator - HP-ID Assembly
Serial Prefix 3040A and above
Service Model 11848A
CHANGES
All Serial Prefixes On the
• J18, J19 - Change the reference designator of J18 to CR18J18, and J19 to
Microfiche Service Manual HP Part 11848-90011 Printed in
U.S.A.
99220
l/l
U.S.A.
: MAY 1990
HEWLETT
PACKARD
CERTIFICATION
Hewlett-Packard Company certifies that this product met its published specifications at the time of shipment.
from the factory. Hewlett-Packard further certifies that its calibration measurements are traceable to the United
States National Bureau of Standards, to the extent allowed by the Bureau's calibration facility, and to the
calibration facilities of other International Standards Organization members.
WARRANTY
This Hewlett-Packard instrument product is warranted against defects in material and workmanship for a period
of one year from date of shipment. During the warranty period, Hewlett-Packard Company will at its option,
either repair or replace products which prove to be defective.
For warranty service or repair, this product must be returned to a service facility designated by HP. Buyer shall
prepay shipping charges to HP and HP shall pay shipping charges to return the product to Buyer. However, Buyer
shall pay all shipping charges, duties, and taxes for products returned to HP from another country.
HP warrants that its software and firmware designated by HP for use with an instrument will execute its
programming instructions when properly installed on that instrument. HP does not warrant that the operation
of the instrument, or software, or firmware will be uninterrupted or error free.
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer,
Buyer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the environmental
specifications for the product, or improper site preparation or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HP SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE BUYER'S SOLE AND EXCLUSIVE REMEDIES. HP SHALL
NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
ASSISTANCE
Product maintenance agreements and other customer assistance agreements are available for Hewlett-Packard
products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service Office. Addresses are provided at
the back of this manual.
SAFETY CONSIDERATIONS
GENERAL
This product and related documentation must be reviewed for familiarization with safety markings and
instructions before operation.
This product is a Safety Class I instrument (provided
with a protective earth terminal).
BEFORE APPLYING POWER
Verify that the product is set to match the available
line voltage and the correct fuse is installed.
SAFETY EARTH GROUND
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.
SAFETY SYMBOLS
/\ Instruction manual symbol: the product will
/ • \ be marked with this symbol when it
is necessary for the user to refer to the instruction
manual (refer to Table of Contents).
Indicates hazardous voltages.
*
— Indicates earth (ground) terminal.
WARNING I
(
■^■^H^HBIJ hazard. It calls attention to a
procedure, practice, or the like, which, if not correctly
performed or adhered to, could result in personal in-
jury. Do not proceed beyond a WARNING sign until
the indicated conditions are fully understood and met.
Tne
WARNING sign denotes a
WARNING
Any interruption of the protective (ground-
ing) conductor (inside or outside the instrument) or disconnecting the protective earth
terminal will cause a potential shock hazard
that could result in personal injury. (Grounding one conductor of a two conductor outlet
is not sufficient protection).
Whenever it is likely that the protection has
been impaired, the instrument must be made
inoperative and be secured against any unintended operation.
If this instrument is to be energized via an
autotransformer (for voltage reduction) make
sure the common terminal is connected to the
earth terminal of the power source.
Servicing instructions are for use by service-
trained personnel only. To avoid dangerous
electric shock, do not perform any servicing
unless qualified to do so.
Adjustments described in the manual are performed with power supplied to the instrument
while protective covers are removed. Energy
available at many points may, if contacted, re-
sult in personal injury.
Capacitors inside the instrument may still be
charged even if the instrument has been dis-
connected from its source of supply.
CAUTION
operating procedure, practice, or the like, which, if not
correctly performed or adhered to, could result in damage to or destruction of part or all of the product. Do
not proceed beyond a CAUTION sign until the indi-
cated conditions are fully understood and met.
The CAUTION sign denotes a hazard. It calls attention to an
For continued protection against fire
replace the line fuse(s) only with 250V fuse(s)
of the same current rating and type (for example, normal blow, time delay,
repaired fuses or short circuited
fuseholders.
etc.).
hazard,
Do not use
ATTENTION
Static Sensitive
Devices
This instrument was constructed in an ESD (electro-static discharge)
conductor devices used in this instrument
by static discharge.
Depending on the magnitude of the charge, device substrates can
be
charge. The results can cause degradation of device performance,
early failure, or immediate destruction.
These
tact, separation of materials, and normal motions of persons
working with static sensitive devices.
When handling or servicing equipment containing static sensitive
devices,
age or destruction.
Only those who are thoroughly familiar with industry accepted
techniques for handling static sensitive devices should attempt to
service circuitry with these devices.
protected environment. This is because most of the semi-
are
susceptible to damage
punctured or destroyed by contact or mere proximity of a static
charges
are generated in numerous ways such as simple con-
adequate
precautions must
be
taken
to
prevent device dam-
In all instances, measures must be taken to prevent static charge
build-up on work surfaces and persons handling the devices.
For further information on ESD precautions, refer to "SPECIAL
HANDLING CONSIDERATIONS FOR STATIC SENSITIVE
DEVICES" in Section VIII Service Section.
Model 11848 A
Table of Contents
TABLE OF CONTENTS
General Information 1
Introduction 1
Instruments Covered by this Manual 1
Specifications 1
Performance Tests 1
Calibration 1
Documentation Updating 3
Safety Considerations 3
Accessories Supplied 5
Recommended Test Equipment 6
Options Available 6
INSTALLATION '. . 7
Introduction 7
Initial Inspection 7
Preparation for Use 7
Storage and Shipment 11
Troubleshooting Helps in the Main System Software 21
Running the Diagnostic Program 22
Features of the Diagnostic Program 22
Option 301 22.1
General Information 22.1
INSTALLATION 22.7
Troubleshooting 22.13
Replaceable Parts 23
Introduction to this Section 23
Reference Designations and Abbreviations Used in this Manual 23
Replaceable Parts List 23
Mechanical and Chassis Part Locations and Reference Designations 24
Recommended Spares List 24
Disassembly 77
Schematic Symbology and Schematic Diagram Notes 78
Cross Reference Index 89
Block Diagram Notes 90
rev.!5NOV90
Model 11848A General Information
General Information
INTRODUCTION
This Service Manual contains information for installation of the Hewlett-Packard Model 11848A
Phase Noise Interface.
The HP 11848A is the Phase Noise Interface for the HP 3048A Phase Noise Measurement System.
The Interface supports several measurement techniques for phase noise and AM noise measurements.
Inside the Interface are the phase detectors, amplifiers, filters, and switches necessary to measure
phase noise over a frequency range of 5 MHz to 18 GHz. An input for an external phase detector
outside that frequency range is also provided. The built-in sources allow the system to functionally
check all of its signal handling circuits to insure proper operation before measurements are made.
INSTRUMENTS COVERED BY THIS MANUAL
Attached to the instrument is a serial number plate. The serial number is in the form 1234A00123.
The first four digits and the letter are the serial prefix. The last five digits form the sequential suffix
that is unique to each instrument.
SPECIFICATIONS
The specifications for the Interface are included in the specifications for the HP 3048A Phase Noise
Measurement System which specifies the entire system. There are no specifications that apply to the
Interface alone.
PERFORMANCE TESTS
The performance Tests for the Interface are included in the performance tests for the HP 3048A Phase
Noise Measurement System. These tests can be found in the HP 3048A System Calibration Manual.
It is not necessary to run the System performance tests after the System is initially installed. These
tests are performed at the factory before shipment. However, performance tests should be run every
12 months or whenever the Interface has been repaired.
CALIBRATION
The calibration of the Interface consists of generating correction factors for the various measurement
paths and storing them on the software disc for corrections of 0 Hz to 100 kHz as CALDATALO and
100 kHz to 40 MHz as CALDATAHI. Stored with CALDATAHI are the nominal voltages (VNOMs)
to set each internal source to its nominal frequency.
The calibration of the Interface is only part of the calibration of the HP 3048A Phase Noise
Measurement System and must be done with the System. For calibration refer to the HP 3048A
Phase Noise Measurement System
Calibration
Manual.
rev.30MAY89
General Information
The complete calibration for a HP 3048A Phase Noise Measurement System includes the following:
1.
HP 3561A Dynamic Signal Analyzer bench calibration.
2.
RF Analyzer bench calibration. (If an RF analyzer is configured in the system.)
3.
HP 3048A Functional Checks.
4.
HP 11848A Adjustments. (The adjustments should only be run if the Functional Checks show a
problem.)
5.
HP 3048A System Calibration Option 2. (This is total calibration of the HP 11848A Interface's
measurement paths.)
6. HP 3048A Performance Tests.
Before calibrating the System, the HP 3561A Dynamic Signal Analyzer and any configured RF analyzer
should be separately bench calibrated if they are beyond their calibration period.
Model 11848A
NOTE
Measurement of phase noise is a ratio measurement where both the
numerator (the noise power) and the denominator (the carrier's power)
of the ratio are measured by the same system spectrum analyzer(s). The
accuracy of this relative measurement depends on the amplitude linearity
of the spectrum analyzer. A precision attenuator is
the linearity specification of the spectrum
calibration of the spectrum analyzer
will
analyzer.
be
traceable
used,
in turn, to verify
The amplitude linearity
to the National Bureau
of Standards (NBS) if the precision attenuator and other instrumentation
used to perform the calibration is traceable to NBS.
The following are guidelines as to when the Interface hardware calibration and System performance
tests should be run:
• It is not necessary to calibrate the Interface after the System is initially installed. The calibration
procedure is done at the factory before shipment, and the unique calibration data for the Interface
is stored on a software disc. This disc is included within the software set shipped with your
Interface.
• Whenever the environment changes 10° C or more, Option 1 calibration should be run to generate
new calibration data for the Interface to ensure accurate System performance.
• Once a year, after a repair of the Interface, or when a problem is suspected in the Interface the
following test should be run to ensure accurate System measurement results:
a. Functional Checks.
b.
Adjustments. (The adjustments should only be run if the Functional Checks show a problem.)
c. Calibration Option 2. (This is a total calibration of the Interface measurement paths.)
d. Performance Tests.
The performance tests can be run more often if desired to ensure that the system meets the published
specifications contained in Section 1 of the HP 3048A Operating Manual.
It is suggested that the performance test be run in the following order:
1.
Spur Accuracy Performance Test (spurious signal).
2.
Noise Flatness Performance Test. (This test need only be run if an RF analyzer is included in
the system configuration.)
3.
Noise Floor Performance Test.
Model 11848A General Information
DOCUMENTATION UPDATING
An instrument manufactured after the printing of these manuals may have a serial-number prefix that
is not listed on the manual title page. Having a serial-number prefix that is greater than that shown on
the title page indicates that the instrument is slightly different from those documented in the manual.
In this case, your manual may be provided with updating information to make it as current as possible.
This updating information contains all major change information that applies to instruments beyond
the serial-prefix range defined on the title page. Minor changes may not be included but will be covered
in subsequent updates you can receive by joining the Documentation Update Service.
A Description of the Manual Update Packet
A Manual Update packet consists of replacement and addition pages which should be incorporated in
your manual to bring it up to date. (An addition page results when new information won't fit on a
replacement page.)
Signing Up for the Documentation Update Service
Hewlett-Packard offers a Documentation Update Service that will provide you with further updates
and changes as they become available. If you have not received update information that matches the
serial number of your instrument, you can receive this information through the Update Service.
If you operate or service instruments with different serial prefixes, we strongly recommend that you
join this service immediately to ensure that your manual is kept current.
For more information, refer to the Documentation Update Service reply card included in this manual
or contact:
Hewlett-Packard Company
Technical Writing Department
24001 E. Mission-TAF C-34
Spokane, WA 99220
(509) 922-4001
Also,
if you join the update service, you can indicate whether you choose to be contacted in the
future about the quality of the documentation you receive. We are constantly trying to provide the
best documentation possible and periodically survey our customers as to their expectations and the
usability of the manuals we provide.
SAFETY CONSIDERATIONS
The Interface is a Safety Class I instrument (that is, provided with a protective earth terminal). Before
operation, look over the Phase Noise Interface and its related documentation to get familiar with
safety markings and instructions. Refer to the Safety Considerations page found at the beginning of
this manual for a summary of the safety information. Safety information that applies to the specific
task at hand (for example, installation) is found in this manual.
3
General Information
^=CS
S? Mini-Circuits
»Stt
1
E
SPUTT6R
2F6C-S-*!
Model 11848A
Fuses
50n Termination
Noise Floor Test Fixture
Cable Assembly; BNC
to SMB
\ *IT% HEWLETT
1
ffg|
PACKARD
MICRO
FLEXIBLE
OiSC
DOUBLE*
SIDED
L,,: 0WH8-10001
•
RiBhM "»"f
AU
Adapters, Type-N
to BNC
Cables Assemblies;
[r\i J
Si*.
1Z
W-«
sft
the
"•
ot
-
BNC
HP 3048A Software Discs
Figure 1. Accessories Supplied
rev.l5DEC87
Model 11848A
ACCESSORIES SUPPLIED
The accessories supplied are pieces of equipment that are shipped with every Interface. The accessories
are shown in Figure 1.
Line Power Cable. The line power cable may be supplied in several plug configurations, depending
on the destination of the original shipment. Refer to PowerService manual.
Fuses.
Fuses with a 0.75A rating for 115 Vac (HP part number 2110-0063) and a 0.5A rating for 230
Vac (HP part number 2110-0012) are supplied. One fuse is factory installed according to the voltage
available in the country of original destination. Refer to
Service manual.
HP 3048A Software Discs and Manual Set. The HP 3048A software set and associated manuals are
shipped with the Interface.
HP 3048A Software Set (HP part number 11848-61026).
HP 11848A Service Manual (HP part number 11848-90004).
HP 3048A Operating Manual (HP part number 03048-90001).
HP 3048A Reference Manual (HP part number 03048-90002).
Power
General Information
Cables
in the Installation section of this
Requirements in the Installation of this
50fi Termination. This 50fi load is used to terminate the Interface's Spectrum Analyzer output if no
RF spectrum analyzer is available (HP part number 1250-0207).
Adapters, Type-N to BNC. Three adapters are provided for system operation (HP part number
1250-0780).
Cable Assemblies: BNC. Two 30 cm (12 in.) cables are provided for system operation (HP part
number 8120-1838).
Noise Floor Test Fixture. This test fixture is used to run performance tests (HP part number
11848-61032).
Cable Assembly: BNC to SMB. This cable assembly can be used during troubleshooting (HP part
number 08954-60105).
5
General Information
RECOMMENDED TEST EQUIPMENT
Table 1 lists the test equipment and accessories recommended for use in testing, adjusting, and servicing
the Interface. If any of the recommended equipment is unavailable, instruments with equivalent
minimum specifications may be substituted.
Tests for the Interface are performed during the HP 3048A Performance Tests which are available in
the HP 3048A Operating Manual in Appendix B, Performance Tests.
Table 1. Recommended Test Equipment
Model 11848A
OPTIONS AVAILABLE
Options are variations on the standard instrument which can be ordered during the purchase.
Electrical Options
Option 201: Add High Frequency Phase Detector. This option adds a 1.2 to 18 GHz phase
detector to the Interface. This phase detector extends the range of carrier frequencies that can be
demodulated within the Interface without external down conversion by the System. All of the HP 3048A
specifications from 1.6 to 18 GHz carrier frequency are valid with this option.
Instrument Type
Dynamic Signal Analyzer
Counter (550 MHz)
Function Generator
Oscilloscope
Power Meter and Sensor
* A=Adjustments, C=Functional Checks, P=Performance
** The HP 3561A is included with the HP 3048A system.
HP 3561A
HP 5383A, HP 5386A
HP3312A, HP3325A
HP1740A
HP 435B or HP 436A with
Model Number
HP8481AorHP8482A
Tests,
Troubleshooting
Use*
A,C,P,T "
P
P.T
T
T
Mechanical Options
Option 907: Front-Handle Kit. Front handles are provided when Option 907 is ordered. After shipment,
you can order a Front-Handle Kit as HP part number 5061-9689.
Option 908: Rack-Flange Kit. Rack flanges are provided for the HP 11848A Phase Noise Interface
when Option 908 is ordered. After shipment, you can order a Rack-Flange Kit as HP part number
5061-9677.
Option 909: Rack-Flange and Front-Handle Combination Kit. This is not a Front-Handle Kit and a
Rack-Flange Kit packaged together; it is a unique part that combines both functions. Combination kits
are provided for the HP 11848A Phase Noise Interface when Option 909 is ordered. After shipment,
you can order a Rack-Flange and Front-Handle Combination Kit as HP part number 5061-9683.
6
rev.l5DEC87
Model 11848A
INTRODUCTION
This section provides the information needed to install the HP 11848A Phase Noise Interface. Included
is information pertinent to initial inspection, power requirements, line voltage selection, power cables,
environment, storage, and shipment.
INITIAL INSPECTION
Installation
INSTALLATION
WARNING
To avoid hazardous electrical
there are signs of shipping damage to any portion of the outer enclosure
(covers
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. Procedures for checking electrical
performance are given in the Confidence Check found in the HP 3048A Operating Manual. If the
contents are incomplete, if there is mechanical damage or defect, or if the instrument does not pass
the electrical performance test, notify the nearest Hewlett-Packard office. If the shipping container
is damaged, or the cushioning material shows signs of stress, notify the carrier as well as the
Hewlett-Packard office. Keep the shipping materials for the carrier's inspection.
PREPARATION FOR USE
Power Requirements
The HP 11848A requires a power source of 100 Vac (90 to 105 Vac), 120 Vac (108 to 126 Vac), 220 Vac
(198 to 231 Vac), or 240 Vac (216 to 252 Vac), 47.5 to 440 Hz single phase. Power consumption is
260 VA maximum.
This is a Safety Class I product (i.e., provided with a protective earth
terminal).
Mains power source to the product input wiring terminals, power
supplied power cord set. Whenever it is likely that the protection has been
impaired,
any unintended operation.
shock,
and panels).
An uninterrupted safety earth ground must
the instrument must be made inoperative and be secured against
do not perform electrical tests when
WARNING
be
provided from the
cord,
or
If this instrument is to be energized via an external autotransformer for
voltage
earth pole of the power source.
BEFORE PLUGGING THIS INSTRUMENT into the Mains (line) voltage,
be sure the correct
reduction, make sure that the common terminal is connected to the
CAUTION
voltage
and fuse have been
selected.
7
Installation
Model 11848A
A rear-panel, line power module permits operation from 100, 120, 220, or 240 Vac. The number visible
in the window (located on the module) indicates the nominal line voltage to which the instrument
must be connected. Verify that the line voltage selection and the fuse are matched to the power source.
Refer to Figure 2, Line Voltage and Fuse Selection.
Two fuses are supplied with each instrument. One fuse has the proper rating for 110/120 Vac line
operation (HP part number 2110-0063; 0.75A, 250V, non-time-delay). The other fuse is rated for
200/220 Vac operation (HP part number 2110-0012; 0.5A, 250V, non-time-delay).
One fuse is installed in the instrument at the time of shipment. The rating of the installed fuse is
selected according to the line voltage specified by the customer. If the voltage is not specified, the
rating of the installed fuse will be selected according to the country of destination.
WARNING
For protection against fire
normal
blow
fuse with the correct current rating.
hazard,
the line fuse should only be a 250V
Power Cables
WARNING
BEFORE CONNECTING THIS INSTRUMENT, the protective earth
terminal of the instrument must be connected to the protective conductor
of the (mains) power
socket outlet provided with a protective earth contact. The protective action
must not be negated by the use of an extension cord (power
a protective conductor (grounding). Grounding one conductor of a two
conductor outlet is not sufficient protection.
This instrument is equipped with a three-wire power cable. When connected to an appropriate ac power
receptacle, this cable grounds the instrument cabinet. The type of power cable plug shipped with each
instrument depends on the country of destination. Refer to Table 2 on for the part numbers of the
power cables and Mains plugs available.
cord.
The mains plug shall only be inserted in a
cable)
without
Mating Connectors
Coaxial Connectors. Coaxial mating connectors used with the Phase Noise Interface should be either
the 50-ohm BNC male connectors or 50-ohm Type-N male connectors that are compatible with those
specified in US MIL-C-39012.
8
The application note, "Principles of Microwave Connector Care" (HP part number 5958-7442) can help
you improve measurements and reliability. Suggestions in the application note will help you get the best
performance from all microwave connectors. It will show what to look for when cleaning and inspecting
connectors (in order to preserve their precision and extend their life) and how to make the best possible
microwave connections (improving the accuracy and repeatability of all your measurements).
Model 11848A
Installation
Operating voltage is shown
in module window.
Selection
1.
Open cover door, pull the FUSE PULL lever and rotate to left. Remove the fuse.
2.
Remove the Line Voltage Selection Card. Position the card so the line voltage appears at top-left
corner. Push the card firmly into the slot.
3. Rotate the FUSE PULL lever to its normal position. Insert a fuse of the correct value in the holder.
Close the cover door.
of
Operating Voltage
Figure 2. Line
Voltage
and
Fuse Replacement
and Fuse Selection
Operating Environment
The operating environment should be within the following limitations:
Temperature 0°C to +55°C
Humidity 5% to 95% (maximum wet bulb temperature = 40°C)
Altitude <4600 meters (15 000 feet)
Airflow 5.8 mm (0.23 in.) minimum clearance underneath the
instrument and sufficient clearance behind the
instrument for air flow that is not obstructed.
Rack Mounting
Rack mounting information is provided with the rack mounting kit. If the kit was not ordered with the
instrument as an option, it may be ordered through the nearest Hewlett-Packard office. For rack-mount
kit part numbers, refer to Mechanical Options in the
General
Information section of this manual.
9
Installation
Model 11848A
Table 2. AC Power Cables Available
Plug
Type
250V 8120-1351
250V
250V 8120-1689
125V
100V
(Same plug as above)
250V
<co»
250V
Cable
HP Part
Number
8120-1703
8120-1369
8120-0696
8120-1692
8120-1378
8120-1521
8120-1751
8120-4753
8120-4754
8120-2104
8120-2296
8120-3997
8120-0698
Plug
Description
90°/STR BS1363A*
90°/90°
STR/STR
NZSS198/ASC112*
STR/90°
STR/STR*
STR/90
STR/STR NEMA5-15P*
STR/90
STR/STR
STR/STR
STR/90
STR/STR SEV1011
1959-24507
Type 12
STR/90
STR/90
STR/STR NEMA6-15P
0
0
0
0
0
Cable
Length
(inches)
90
90
79
80
79
79
80
80
90
90
90
79
79
177
90
Cable
Color
Mint Gray
Mint Gray
Gray
Gray
Mint Gray
Mint Gray
Jade Gray
Jade Gray
Jade Gray
Dark Gray
Dark Gray
Gray
Gray
Gray
Black United States,
For Use
In Country
United Kingdom,
Cyprus, Nigeria,
Rhodesia,
Singapore
Austrailia,
New Zealand
East and West
Europe, Saudi
Arabia, Egypt,
(unpolarized in
many nations)
United States,
Canada, Mexico,
Phillipines, Taiwan
U.S./Canada
Japan only
Japan only
Switzerland
Canada
250V 8120-2956
8120-2957
8120-3997
250V 8120-4211
8120-4600
250V
Part number shown for plug is industry identifier for plug only. Number shown for cable is HP Part Number for complete
cable including
8120-1860
8120-1575
8120-2191
8120-4379
plug.
E = Earth Ground; L = Line; N — Neutral; STR = Straight
The HP-IB address is selectable using rocker switches on the rear-panel of the Phase Noise Interface.
These rocker switches are set up in a binary format with switch number 1 as the least significant digit
and switch number 5 as the most significant digit. (Switches 6 and 7 are not used.) Any one of 31
HP-IB addresses can be set (00 through 30).
The address of the HP 11848A is set to 20 at the factory (switches 3 and 5 high; 16 + 4 = 20). Refer
to Figure 3.
STORAGE AND SHIPMENT
Environment
The instrument should be stored in a clean, dry environment. The following environmental limitations
apply to both storage and shipment:
Temperature -55°C to +75°C
Humidity 5% to 95% (maximum wet-bulb temperature = 40°C)
Altitude 15 300 meters (50 000 feet)
Packaging
Original Packaging. Containers and materials identical to those used in factory packaging are available
through Hewlett-Packard offices. If the instrument is being returned to Hewlett-Packard 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.
11
Installation Model 11848A
Other Packaging. The following general instructions should be used for repackaging with commercially
available materials:
1.
Wrap the instrument in heavy paper or plastic. (If shipping to a Hewlett-Packard office or service
center, attach a tag indicating the service required, return address, model number, and full serial
number.)
2.
Use a strong shipping container. A double wall carton made of 2.4 MPa (350 psi) test material is
adequate.
3.
Use enough shock-absorbing material (75 to 100 mm layer; 3 to 4 in.) around all sides of the
instrument to provide firm cushion and prevent movement in the container. Protect the front
panel with cardboard.
4.
Seal the shipping container securely.
5.
Mark the shipping container FRAGILE to ensure careful handling.
12
Model 11848A
General
The HP 11848A Phase Noise Interface is the central instrument in the HP 3048A Phase Noise
Measurement System. It is a collection of circuits configured under computer control to make accurate
phase-noise measurements on a wide variety of devices-under-test and using several test methods.
Besides the Interface, the System includes:
Some of the interface circuits in the HP 11848A Phase Noise Interface include:
Service
Principles of Operation for the Block Diagram
• a Fast-Fourier-Transform (FFT) spectrum analyzer (the HP 3561A Dynamic Signal Analyzer)
that measures the demodulated phase noise as a function of frequency offset from the carrier,
• optionally, an additional RF spectrum analyzer that extends the frequency-offset measurement
range,
• optionally, reference sources with high spectral purity, and
• the system controller.
• numerous signal-routing switches,
• an RF phase detector and optionally a microwave phase detector (1) for demodulation of phase
noise to be measured by the spectrum analyzers and (2) to provide a tune voltage to phase lock
the input sources in quadrature when the phase-noise-using-a-phase-lock-loop method is used,
• various networks which process the phase detector output for voltage control of the input sources,
• various networks which process the noise for measurement by the spectrum analyzer,
• detectors which sense erroneous measurement conditions,
• four RF sources for system calibration verification, and
• control circuits which interface with the controller via HP-IB.
The maximum frequency offset from the carrier that can be measured by the system is 100 kHz for
the standard system and 40 MHz with an additional RF spectrum analyzer (such as the HP 3585A)
supported by the system.
NOTE
In the text that follows, the primary discussion of a functional circuit
is indicated by lettering the circuit description in boldface, for example,
RF Phase Detector. The term "Interface" refers to the HP 11848A
Phase Noise Interface; "System" refers to the HP 3048A Phase Noise
Measurement System. An RF spectrum analyzer is assumed to be connected
to the System.
Measurement Modes
To clearly understand the functions of the Interface, it is helpful to see the relationship of the Interface
to the other System instruments and the device-under-test in a phase noise measurement. Refer to
Figure 4.
Figure 4 shows the most basic measurement mode where the noise on the source has been demodulated
externally and fed into the front-panel NOISE INPUT. In this mode of operation the Interface serves
mainly to condition (amplify and filter) the noise. The conditioned noise is then measured (in the
frequency domain) by the spectrum analyzers. The measured noise is then analyzed, mathematically
manipulated, and plotted by the controller. The noise need not be exclusively phase noise; it could also
be AM (from an AM detector), FM (from an FM discriminator), or baseband (0.01 Hz to 40 MHz)
noise.
13
DEMODULATOR
HPU848A PHASE NOISE INTERFACE
Model
PHASE
DETECTOR
OUTPUT
TO
HP3561A
INPUT
Figure 4. Noise Measurement with an External Demodulator
HP11848A
PHASE NOISE INTERFACE
TUNE VOLTAGE
OUTPUT
PHASE
DETECTOR
OUTPUT
TO
HP3561A
INPUT
SPECTRUM
ANALYZER
Figure 5. Noise Measurement with the Internal Phase Demodulator
Model 11848A
In the diagram, the Low-Pass Filter removes carrier-related signals to reject them from the circuits
that follow. The Low-Noise Amplifier improves the measurement noise floor. The Output Conditioning
circuits set the proper level to the FFT spectrum analyzer and limit the frequency range of the noise
for the frequency segment being measured.
Figure 5 shows the more common measurement mode where two RF sources are phase-locked together
in quadrature (that is, the phase difference of the sources is 90°). In this situation the Phase Detector
outputs a signal proportional to the sum of the phase fluctuations on the two sources. The output from
the Phase Detector is switched (by the Input Switch) into the same path as in the previous example.
For this method to give valid results several conditions must be met.
Service
• The L and R ports of the Phase Detector may be interchanged, and either source may be the local
oscillator (the higher level "L" source). Neither source should exceed the specified maximum level.
• Either source can be the VCO (Voltage-Controlled Oscillator), but it must be tuneable with dc
(dc FM) and compatible with the other source and the Interface.
• The VCO must be characterized (its tuning constant measured) before valid measurements can
be made. This is done by the software after some general characteristics are input by the user.
• The two signals must remain in quadrature during the measurement. The Interface meter (not
shown) is useful for visually monitoring phase quadrature drift between the two sources.
• The rms sum of the phase noise of both sources is measured inseparably.
• The conditioning circuits within the Interface must have been characterized before any measure-
ments are made with the Interface. This is usually done annually; calibration data is stored in
mass storage.
NOTE
When configuring the system for a phase-noise measurement, one source is
arbitrarily defined as the "Device-under-Test" (DUT) and the other source
as the
"Reference".
Either source can be the L source and either source can
be the VCO.
Characterization of the phase-lock loop (PLL) is critical. If the loop is incorrectly set up, the loop may
not acquire lock, may be unstable or even oscillate (create discrete FM), may track out the phase noise,
or may generate erroneous results. Selection of the proper loop parameters is the task of the controller
which, based on measured and user-input data, chooses the device parameters in the Tune Voltage Conditioning circuits which best match the VCO. The parameters that the controller can manipulate
in the PLL are gain, offset, and frequency-response shaping (selection of poles and zeros).
A4 Phase Detector Assembly
Refer now to the main Block Diagram. The Phase Detector Assembly can conveniently be broken
into three functional circuit blocks: (1) the phase demodulation circuits, (2) calibration signal routing
circuits, and (3) tune-voltage conditioning circuits.
Phase Demodulation Circuits
If the phase noise on the device-under-test (DUT) has been demodulated externally, the demodulated
phase noise is fed directly into the Interface via the front-panel NOISE INPUT connector. More
commonly, the RF signal is demodulated by an internal RF or an optional microwave phase detector.
15
Model 11848A
The phase detectors are doubly balanced mixers. The standard RF Phase Detector covers the RF
input range 5 to 1600 MHz; the Microwave Phase Detector (a chassis-mounted part) covers the range
1.2 to 18 GHz. With either detector, when the LO (L) and signal (R) inputs are in quadrature (that
is,
when the phase difference between the two signals is 90°), the detector's output is proportional to
sum of the phase fluctuations of the two sources. The phase detector is selected by switch K13.
At this point the demodulated phase noise is fed into circuits that condition the signal to be measured
by the spectrum analyzers or for voltage control of an external, voltage-tuneable source. Switch K1
selects either the phase detector output or an external input. Kl also routes the signal from the NOISE
INPUT to switch K12 when an internal phase detector has been selected.
NOTE
The circuits in the following discussions process
"low-frequency"
baseband
signals (actually dc to 40 MHz) which are the demodulated phase noise from
the RF and
to the signal from the input sources, the following convention is
microwave
input
sources.
To relate these low-frequency signals
used:
the
"noise signal" refers to the demodulated phase noise, "level" refers to the
phase deviation of the phase noise, and "frequency" refers to the
offset
from
the carrier (corresponding to the rate of the phase modulation).
Two filters in series, the 200 MHz Low-Pass Filter and the 60 MHz Low-Pass Filter, remove unwanted
high-frequency components from the input noise signal itself or the internal phase detectors. Both
filters are constant-resistance (or diplexer) types which match the 50f2 source impedance in both the
passband and stopband. The 200 MHz Low-Pass Filter is a simpler, single-pole type; it comes first
since it more efficiently terminates high-frequency mixing products. The 2 MHz Low-Pass Filter is
switched in by K8 and K9 for carrier frequencies below 95 MHz. It too is a constant-resistance type.
The output of the 60 MHz Low-Pass Filter is sensed by the Overload Detector. Should the noise
signal level at that point exceed IV peak, the detector via the Overload Flip-Flop de-energizes switches
Kl,
K12, Kll, K14, and K10 (that is, they are set to the state shown in the block diagram), and
the overloading noise signal is routed to the front-panel SPECTRUM ANALYZER connector. The
overloading noise signal is thus prevented from overdriving the active circuits that follow. The Overload
Flip-Flop also lights the front-panel OVERLOAD annunciator. The condition of the Overload Flip-Flop
is read by the FFT spectrum analyzer (used as a dc voltmeter) via the 21.5 kO resistor and switch F6
in the A3 Analyzer Interface Assembly. This readback function is shared by the Out-of-Lock Flip-Flop.
The Low-Noise Amplifier (LNA) is switched in by K11 and K14 for maximum sensitivity whenever
the noise signal level permits. The two switches are switched together. The gain of the amplifier is 40
dB open circuit.
For frequencies (that is, phase noise offsets) greater than 100 kHz, the measurement is made at the
front-panel SPECTRUM ANALYZER connector where the RF spectrum analyzer is connected. The
signal to this port comes from switch K9 through switches Kll and K14 (and the Low-Noise Amplifier
when switched in) and switch K12. If an RF spectrum analyzer is not connected, the SPECTRUM
ANALYZER connector must be terminated in 50ft to preserve calibration.
For frequencies less than 100 kHz, the measurement is made at the front-panel TO HP 3561A INPUT
connector, where the FFT spectrum analyzer is connected. When the Low-Noise Amplifier is switched
in, the signal to this port comes from switch K9 through switch Kll, the Low-Noise Amplifier, S7, and
various switches, amplifiers, and filters in the A3 Analyzer Interface Assembly. When the Low-Noise
Amplifier is bypassed, the path from switch K9 is through Kll, K14, K12, S8, and the circuits in A3.
Switch K12 routes the noise signal from Kl or K14 to the output paths to be discussed shortly.
When the noise signal from Kl is selected, the output of the Low-Noise Amplifier (with its series 50O
resistor) is terminated in 50fi. Similarly, when the noise signal from K14 is selected, the signal from
Kl is terminated in 50O.
Model 11848A
The output from K12 is routed as follows:
Calibration Signal Routing Circuits
During system hardware calibration (which is normally run annually to generate new calibration
coefficients), the controller runs a series of tests to characterize the transfer function of many of the
circuits in the Interface. The signal sources used during this calibration are the noise source in the
FFT spectrum analyzer (when the frequency is less than 100 kHz) and the tracking generator in the
RF spectrum analyzer (for frequencies to 40 MHz). The noise source in the FFT spectrum analyzer is
also used when the Functional Tests are requested.
Service
• To the front-panel SPECTRUM ANALYZER connector through a high-pass filter formed by an
RLC network. The filter prevents overloading the RF spectrum analyzer by blocking low-frequency
signals (<50 kHz). (Note that phase noise typically increases as the offset frequency decreases.)
• To switch S8 for further processing on the A3 Analyzer Interface Assembly eventually to reach
the front-panel TO HP 3561A INPUT connector.
• To the front-panel AUX MONITOR connector via Buffer 1. The dc path for the noise signal is
through the 5 kQ resistor. The ac path is through the buffer amplifier and the 0.01 fjF capacitor.
The AUX MONITOR port is normally used to study (in the time domain) the quality of the noise
signal being measured by the spectrum analyzer and to assist in obtaining a proper beat note
during initial setup of the sources. The oscilloscope must have a high input impedance (>1 Mfi).
• To the 10 Hz/50 kHz High-Pass Filter on the A3 Analyzer Interface Assembly.
The noise source in the FFT spectrum analyzer is connected to the rear-panel NOISE INPUT
FROM HP 3561A SOURCE OUTPUT connector. It is then routed through the A3 Analyzer Interface
Assembly (through a 20 dB Pad) to switch K5. The tracking generator in the RF spectrum analyzer
is connected to the rear-panel INPUT FROM HP 3585A TRACKING GENERATOR connector. It is
then routed through switch K7 and a 35 dB pad (Pad 4) to K5.
Switch K5 routes the calibration input sources to K2 via a series of 3 dB pads and switches (Pad 1,
Pad 2, Pad 3, and switches K4 and K3). Having two switches and three pads improves the isolation in
the open state. K4 and K3 switch together.
Tune-Voltage Conditioning Circuits
Refer now to switch K10, which is at the output of switch K9. When phase noise is measured using
a phase-lock loop, the noise signal from K10 is the signal which, after further processing, tunes the
external voltage-controlled oscillator (VCO) to phase lock it to a second source. The signal path splits
at the output of Buffer 2 to drive two tuning ports: the front-panel and rear-panel TUNE VOLTAGE
OUTPUT connectors. The path to the rear panel is for user convenience, and is inverted to that of
the front-panel.
A fixed 12 dB Amplifier, a programmable amplifier (Gain 1), a fixed 6 dB pad (Pad 4), and a second
programmable amplifier (Gain 2) set the path gain up to the Integrator. The Integrator has very high
gain at low-frequencies to hold the phase detector error near zero in the presence of source drift.
Noise signals in excess of 2.5V (positive or negative) at the input and output of the Integrator are
sensed by the Comparator which trips the Out-of-Lock Flip-Flop. This condition occurs when the two
input sources go out of lock or when the tune voltage exceeds 25% of its entered tuning range or when
a phase transient exceeds 0.25 rad even though the sources are still locked. The flip-flop shorts the
feedback path of the Integrator (forcing it to unity gain) and lights the front-panel OUT OF LOCK
annunciator. The condition of the Out-of-Lock Flip-Flop is read by the FFT spectrum analyzer (used
as a dc voltmeter) via the 46.4 kf2 resistor and switch F6 in the A3 Analyzer Interface Assembly. This
readback function is shared by the Overload Flip-Flop.
17
Service
Model 11848A
The output of the Integrator, where the panel Meter is placed, is the most sensitive point to monitor
phase quadrature error. When a measurement is made using a phase-lock loop, the meter indicates
whether or not the control voltage being sent to an external VCO is in an acceptable range. In particular,
it warns the user when one of the input sources is drifting (before the loop unlocks). Note, however,
that the meter will also read near zero when phase lock is broken because the average dc voltage in a
beatnote between two sources is near zero and the Out-of-Lock Flip-Flop forces the Integrator to unity
gain.
Switch S3 (with switch K10) closes the phase-lock loop. S3 is opened when a noise measurement
is made without using a phase-lock loop to uncouple the output circuits but leave the Meter in.
Attenuator 2 can be set to either 0 or 6 dB; it controls the signal level into the Summing Junction.
The Summing Junction has several functions:
• It sums the phase-error signal with a programmable dc output from DAC 1 which tunes the
external VCO.
• It routes the noise source from the FFT spectrum analyzer (via switch S1) to the output
circuits when the error transfer function of the closed phase-lock loop is measured. From this
measurement, correction factors are calculated in the phase-noise measurement. (S2 is unused.)
• It enables the Search Oscillator when switch S4 is closed and the phase-lock loop is unlocked.
The oscillator starts automatically when the loop goes out of lock and provides a 1.6 Hz search
signal which sweeps the external VCO until the VCO is captured by the loop. When the Search
Oscillator is oscillating, the Oscillation Detector sets the Out-of-Lock Flip-Flop.
Before the tune voltage is applied to the VCO (connected to the rear-panel TUNE VOLTAGE
OUTPUT connector), it passes through programmable Lag-Lead Network 1, Buffer 2, programmable
Attenuator 1, Buffer 3, and Lag-Lead Network 2. The latter three circuits are duplicated in the
A3 Analyzer Interface Assembly which output the tune voltage to the front-panel TUNE VOLTAGE
OUTPUT connector. (The front-panel output is preferred because of a floating amplifier which breaks
potential ground loops.)
The lag-lead networks shape the tune voltage to give the phase-lock loop maximum low-frequency
gain (for good drift tracking) while maintaining loop stability. The frequency responses of the lag-lead
networks are shown in the block diagram notes. Lag-Lead Network 1 is programmable; the controller
selects the optimum pole and zero frequencies based on the measured tuning characteristics of the VCO.
A3 Analyzer Interface Assembly
The primary function of the A3 Analyzer Interface Assembly is to condition the output noise signal
to be measured by the FFT spectrum analyzer. The noise signal is routed from the A4 Phase Detector
Assembly through switches S7 and S8 in that assembly. The noise signal passes through a series of
amplifiers and filters.
Gain stage Gain 3 has two parts: (1) a programmable-gain amplifier (6, 12, 20, and 26 dB) with an
output at switch L4 and (2) an additional 6 dB attenuator with its output through switch L3. (The
gains stated for Gain 3 are for the entire path from the input of the amplifier to the output of the
High-Pass Filters. The High-Pass Filters have a passband gain of 6 dB.) The controller sets the gain
so as to present an optimum level for the input to the FFT spectrum analyzer.
After passing through Buffer 1, the signal is low-pass filtered. Since the measurement range of the
FFT spectrum analyzer is 100 kHz, the signal is filtered by the 100 kHz Low-Pass Filter then passed
through one of a set of decade-spaced Low-Pass Filters as selected by switches F0 through F5. The
filters match the default sweep ranges of the FFT spectrum analyzer and remove the high-frequency,
out-of-range components. (The filters match the default sweep ranges even when sweep segments other
than default are selected.)
Model 11848A
After passing through Buffer 2, the signal is high-pass filtered. The decade-spaced High-Pass Filters,
selected by
range of the FFT spectrum analyzer. This is necessary because the noise signal frequently has very
large, low-frequency components due to the nature of phase noise. (As with the Low-Pass Filters,
these filters match the default sweep ranges when other sweep segments are selected.) The AC/DC
Adaptive Coupler, when set to dc, restores the dc component of the noise signal when the need arises
to measure it with the FFT spectrum analyzer. In the ac mode, the AC/DC Adaptive Coupler is a
16 MHz high-pass filter.
The noise signal is finally sent to the front-panel TO HP 3561A INPUT connector via Floating
Amplifier 2 which has a gain of
resulting from ground loops.
H1
through H5, are set to block low-frequency components from dc to one-tenth the sweep
-1.
Having a floating output improves rejection of line-related signals
Service
The remaining circuits in the
of the noise signal by the FFT spectrum analyzer.
The Calibration Oscillator outputs a 100 kHz squarewave. It is switched on when a new measurement
is selected to compare the amplitude calibration of the RF spectrum analyzer relative to the FFT
spectrum analyzer. (The frequency ranges of the two spectrum analyzers overlap at 100 kHz.)
The 10 Hz/50 kHz High-Pass Filter, Peak Detector, and Peak Hold circuits have three functions:
(1) to sense the presence of a beatnote when measuring phase noise using a phase lock loop, (2) to
determine whether to insert the Low-Noise Amplifier in the A4 Phase Detector Assembly, and (3) to
provide signal level information for ranging the RF spectrum analyzer. The first two functions use the
10 Hz high-pass filter; the third function uses the 50 kHz filter (which matches filtering to the RF
analyzer input provided by the 0.068 fiF capacitor at J2 on A4.)
DAC 2, DAC 3, and the DAC SUMMING JUNCTION output a programmable dc voltage to tune three
VCOs: (1) the 400 MHz VCO on A8, (2) the 10 MHz VCXO on A7, and (3) the 10 MHz VCXO on A6.
DAC 3 has 1 mV resolution; DAC 2 has 50 mV resolution. Switch L11 enables the same three VCOs
to be tuned as the VCO in a measurement of phase noise using a phase-lock loop. Note that the VCOs
are all tuned simultaneously. (See the discussions below about the function of these VCOs.)
Attenuator 3, Floating Amplifier 1, and the Lag-Lead Network duplicate the function of Attenuator 1,
Buffer 3, and Lag-Lead Network 2 on the A4 Phase Detector Assembly. The path is enabled by switch
L10.
Floating Amplifier 1 breaks up ground loops on the VCO tune voltage and makes the front-panel
TUNE VOLTAGE OUTPUT the preferred output. (See the discussion on Lag-Lead Network 2 on A4
for the function of the Lag-Lead Network.)
Switch L8 routes the rear-panel TONE INPUT or the NOISE INPUT FROM HP 3561A SOURCE
OUTPUT to the Phase Modulator in the A7 10 MHz Modulated VCXO B Assembly.
A3
Analyzer Interface Assembly do not directly relate to the measurement
A6 10 MHz VCXO A Assembly
The 10 MHz ±100 Hz VCXO (voltage controlled crystal oscillator) provides a very clean, tuneable source
available at the front-panel 10 MHz A connector or the rear-panel 10 MHz SOURCE A OUTPUT OR
AMP INPUT connector. This source can be used as a tuneable VCO for measurement of 10 MHz
sources or in conjunction with the 10 MHz ±1 kHz VCXO in A7 for demonstration purposes. The
Power Amplifier boosts the signal level high enough that it can serve as the signal to the L port of the
input phase detectors.
The switch at the output of the oscillator allows the amplifier to be used by itself in other applications
such as boosting the power level of the 10 MHz ± 1 kHz VCXO in A7.
19
Service
A7 10 MHz Modulated VCXO B Assembly
The 10 MHz ±1 kHz VCXO (voltage controlled crystal oscillator) provides a clean, tuneable source
available at the front-panel 10 MHz B connector. This source can be used as a tuneable VCO for
measurement of 10 MHz sources or in conjunction with the 10 MHz ±100 Hz VCXO in A6 for
demonstration purposes. It can also be phase modulated by the Phase Modulator for testing phase
noise accuracy in the system performance tests.
A8 400 MHz VCO Assembly
The 400 MHz VCO provides a clean, wide-range, tuneable source available at the front-panel 350500 MHz connector. This source can be used as a tuneable VCO for measurement of 350-500 MHz
sources or in conjunction with the 400 MHz Oscillator in A9 to test flatness in phase-noise measurement
or by itself for noise-floor testing using a power splitter and delay line.
Pad 1, Amplifier 1, Pad 2, Amplifier 2, and Amplifier 3 provide the correct level to the front-panel
connector for driving the input phase detector. The 550 MHz Low-Pass Filter removes harmonics of
the signal.
A9 400 MHz Oscillator Assembly
The 400 MHz Oscillator provides a fixed source available at the front-panel 400 MHz connector.
The 50 dB Pad lowers the signal level to reduce the signal-to-noise ratio. The Amplifiers boost the
signal level back up but also add noise of their own. This source is primarily used in conjunction with
the 350-500 MHz VCO in A8 to check the flatness of the broadband noise beyond 500 kHz or for
demonstration purposes.
Model 11848A
A1 HP-IB Input/Output Assembly
The Al HP-IB Input/Output Assembly (not shown in the block diagram) contains the digital circuitry
to interface the controllable hardware with the controller via HP-IB. It also contains the power supplies.
The power supplies are +5V, +15V, and -15V.
Model 11848A
General
Service
Troubleshooting
Troubleshooting
in
the HP
software
HP 3048A Reference Manual
general guidelines
to
Interface
the
can
Interface
itself.
the HP
3048A Phase Noise Measurement System. Several programs
assist
in
isolating
are
discussed below.
as the
Troubleshooting Helps
Some
of the
found
in the
Spcl. Funct'n. A menu
selected
Calibrate System. A series
the Interface.
directly
path
is
or when
being
run may
Interface will generate data that
the program will then abort
features
following list.
or
other menus called.
The
or in
more involved calculations)
used. Normally
the
Interface
in the
measurement data
point
to the
11848A Phase Noise Interface usually begins with troubleshooting a problem
the
fault
to a
System device. Details
for the
faulty System device;
in the
main software which
To
call these programs,
of
Advanced-User Functions will appear from which
of
the
Calibrate System program
has
been repaired.
Interface.
the
System
It is
or in the
usually more efficient
the
Diagnostic program
main software under
Main System Software
are
useful
in
go to the
transfer function measurements
is
stored
For
is too far out of
measurement.
as
calibration factors which
to
correct
Any
example, a catastrophic failure
the
is
difficulties encountered when
limits
main menu
measured phase noise data whenever that signal
invoked only
to be
accepted
to use
isolating
are
in the
on
these programs
these programs until they point
is
then loaded
made
for the
as a
System-supplied main
are
found
in the
the
Help function. Some
to
troubleshoot
the
faulty System device
and
press
the
softkey labeled
the
programs
on
various signal paths
the
controller uses (either
annual System calibration
the
calibration program
of a
high-pass filter
legitimate transfer function;
can be
in the
the
are
in
is
Performance Tests.
Performance Tests
in
the
Interface.
Internal Adjustments. Often small out-of-specification results
Checks
voltage that
Functional Checks. These tests
operational integrity
Diagnostic program
in addition
HP 11848A Control. Arbitrary
from
all
consult
the Diagnostic program
Troubleshoot Mode. When
beyond simple error messages
Control mode which shows
can be
is out of
to
simply indicating out-of-limits data.)
the
controller keyboard
the
Interface state information. Because
the HP
To
verify that
can be run. The
corrected
3048A
by
limits.
of the
are
similar
Reference Manual when running
is
similar
the
failure
means
Interface
is
the
the
of
adjustments, particularly
are an
to the
and
provided
to
Troubleshoot Mode
can be
Interface state when
extension
itself. The
Functional Checks,
complete control
by the HP
this program.)
invoked.
system meets
of a
test
may
of the
test limits
of the
11848A Control program. A single display contains
of the
compactness
the
(a
For
example, tests
the
subset
abort occurred.
its
contain enough clues
Performance Tests that test
but
program.
published specifications, a series
to
point
to a
of
the Performance Tests
if the
condition
are
generally loose.
they attempt
programmable functions
of the
of
state information,
(The
Test Mode)
can be
is due to a dc
to
diagnose
keyboard control feature
is
enabled, information
aborted
or
Functional
the
(The
tests
the
of the
you
to the HP
Interface
of
failure
offset
general
in the
failure
should
of
11848A
21
Service
Running the Diagnostic Program
The Diagnostic program is independent of the main System software. To run the Diagnostic program:
1.
Gather and connect the equipment. You will need, in addition to the faulty Interface, the following
equipment:
• HP 3561A Dynamic Signal Analyzer (preferably the one in the System),
• HP Series 200 or 300 Computer with disc drive and HP-IB, and
• optionally, a printer compatible with the System Controller.
2.
Reset the computer. If the computer is not running BASIC, boot up BASIC 4.0. (BASIC 4.0 is
the supplied operating system. BASIC 2.1 and 3.0 will also work.)
3.
Key in
4.
If a display appears which indicates that the HP 3561 A, HP 11848A, or printer HP-IB addresses
are not correct, you can (1) physically change the address of the device to match the displayed
address or (2) change the displayed address of the device using the cursor control keys (the knob,
arrow keys, tab keys, backspace key, or space bar); then press
an incorrect address, then the device does not respond when it is addressed. (It may be broken
or turned off.) If a printer is not available, it can be deleted at this time.
5.
The display will now show the Task Selection menu screen. This is the main screen for the
Diagnostic program. The program is now ready for troubleshooting the Interface.
LOAD
"Diagnostic" and press RUN.
ENTER.
Model 11848A
If the display still indicates
Features of the Diagnostic Program
Most explanations you will need to use the program are part of the program itself either as prompts
on the bottom line of the display or as entire displays of information.
Softkeys are not used in the program. Instead, highlighted (inverse video) characters are displayed;
pressing a key matching the highlighted character initiates the selected action. Very often the letter
"F in the word "Information" will be highlighted. Pressing "I" immediately brings on to the display
information pertinent to the current display. Use it often. It is the Operating Manual for the Diagnostic
program.
The Diagnostic program is referenced to the Block Diagram found herein. Refer to it frequently.
The program has two basic modes of operation.
• It runs tests, displays results, and in many cases will attempt to pinpoint the failure.
• It gives you arbitrary control over any programmable circuit device in the Interface.
When you use the Diagnostic program to troubleshoot the Interface, the normal procedure is:
1.
Run tests which you think might locate the fault. (When running the test for the first time,
respond with "No" when prompted "Stop on failure?".)
2.
When a failure is noted in a test, rerun the test and request stopping when a failure is detected.
When stopped, request to view the Interface setup.
3.
The display will now show the current state of the Interface and enables you to alter the state
to check the functioning of a suspected circuit. Often a faulty control line will cause a circuit to
malfunction. To check for this,
• Press the key corresponding to the desired type of the circuit. (For example, press "A", for
"Attenuator", if one of the programmable amplifiers is to be checked.)
• Now press "I" to display the information for the circuit type (for example, programmable
attenuators). The information will show the logic control states of all the circuits of that
type.
(At this point, if a printer is attached, you may wish to print the information display.)
• Now return to the previous screen (press "X", for exit) and follow the logic levels through
the control circuits to the (Al) control assembly.
4.
Once the faulty circuit or control line has been isolated, you can continue isolation to the faulty
component or replace the faulty assembly. (Some assemblies are on an exchange program.)
Option 301 Service Supplement
Model 11848A Option 301
General Information
INTRODUCTION
This Service Manual contains information for installation of the Hewlett-Packard Model 11848A
Phase Noise Interface.
The HP 11848A is the Phase Noise Interface for the HP 3048A Option 301 Phase Noise Measure-
ment System. The Interface supports several measurement techniques for phase noise and AM noise
measurements. Inside the Interface are the phase detectors, amplifiers, filters, and switches neces-
sary to measure phase noise over a frequency range of 5 MHz to 18 GHz. An input for an external
phase detector outside that frequency range is also provided. The built-in sources allow the system to
functionally check all of its signal handling circuits to insure proper operation before measurements
are made.
INSTRUMENTS COVERED BY THIS MANUAL
Attached to the instrument is a serial number plate. The serial number is in the form 1234A00123.
The first four digits and the letter are the serial prefix. The last five digits form the sequential suffix
that is unique to each instrument.
General Information
SPECIFICATIONS
The specifications for the Interface are included in the specifications for the HP 3048A Option 301
Phase Noise Measurement System which specifies the entire system. There are no specifications that
apply to the Interface alone.
PERFORMANCE TESTS
The performance Tests for the Interface are included in the performance tests for the HP 3048A
Option 301 Phase Noise Measurement System. These tests can be found in the HP 3048A Option
301 System Calibration Manual.
It is not necessary to run the System performance tests after the System is initially installed. These
tests are performed at the factory before shipment. However, performance tests should be run every
12 months or whenever the Interface has been repaired.
CALIBRATION
The calibration of the Interface consists of generating correction factors for the various measurement
paths and storing them on the software disc for corrections of 0 Hz to 100 kHz as LOWDATA.CAL
and 100 kHz to 40 MHz as HIGHDATA.CAL. Also stored in these files are the nominal voltages to
set each internal source to its nominal frequency.
The calibration of the Interface is only part of the calibration of the HP 3048A Option 301 Phase
Noise Measurement System and must be done with the System. For calibration refer to the HP
3048A Option 301 Phase Noise Measurement System Calibration Manual.
22.1
General Information
The complete calibration for a HP 3048A Phase Noise Measurement System includes the following:
1.
HP 3561A Dynamic Signal Analyzer bench calibration.
2.
RF Analyzer bench calibration. (If an RF analyzer is configured in the system.)
3.
HP 3048A Functional Checks.
4.
HP 11848 A Adjustments. (The adjustments should only be run if the Functional Checks show
a problem.)
5.
HP 3048A System Calibration Option
measurement paths.)
6. HP 3048A Performance Tests.
Before calibrating the System, the HP 3561A Dynamic Signal Analyzer and any configured RF
analyzer should be separately bench calibrated if they are beyond their calibration period.
Model 11848A Option 301
2.
(This is total calibration of the HP 11848A Interface's
NOTE
The measurement of phase noise, as implemented in the HP 3048A, is a
ratio measurement where both the numerator (the noise power) and the
denominator (the carrier's power) of the ratio are measured by the same
system spectrum
analyzer(s).
The accuracy of this measured ratio depends
on the amplitude linearity of the spectrum analyzer. The amplitude linear-
ity calibration of the spectrum analyzer will be traceable to the National
Institute of Standards (NIST) if the instrumentation used to perform the
calibration is traceable to
NIST.
The following are guidelines as to when the Interface hardware calibration and System performance
tests should be run:
• It is not necessary to calibrate the Interface after the System is initially installed. The
calibration procedure is done at the factory before shipment, and the unique calibration data
for the Interface is stored on the software disc.
• Whenever the environment changes
10° C
or more, Option 1 calibration should be run to
generate new calibration data for the Interface to ensure accurate System performance.
• Once a year, after a repair of the Interface, or when a problem is suspected in the Interface the
following test should be run to ensure accurate System measurement results:
a. Functional Checks.
b.
Adjustments. (The adjustments should only be run if the Functional Checks show a
problem.)
c. Calibration Option 2. (This is a total calibration of the Interface measurement paths.)
d. Performance Tests.
The performance tests can be run more often if desired to ensure that the system meets the published
specifications contained in Section 1 of the HP 3048A Option 301 Operating Manual.
It is suggested that the performance test be run in the following order:
1.
Spur Accuracy Test (spurious signal).
2.
Noise Flatness Test. (This test need only be run if an RF analyzer is included in the system
configuration.)
22.2
3.
Internal Noise Floor.
Model 11848A Option 301 General Information
DOCUMENTATION UPDATING
An instrument manufactured after the printing of these manuals may have a serial-number prefix
that is not listed on the manual title page. Having a serial-number prefix that is greater than that
shown on the title page indicates that the instrument is slightly different from those documented
in the manual. In this case, your manual may be provided with updating information to make it as
current as possible. This updating information contains all major change information that applies
to instruments beyond the serial-prefix range defined on the title page. Minor changes may not be
included but will be covered in subsequent updates you can receive by joining the Documentation
Update Service.
A Description of the Manual Update Packet
A Manual Update packet consists of replacement and addition pages which should be incorporated
in your manual to bring it up to date. (An addition page results when new information won't fit on
a replacement page.)
Signing Up for the Documentation Update Service
Hewlett-Packard offers a Documentation Update Service that will provide you with further updates
and changes as they become available. If you have not received update information that matches
the serial number of your instrument, you can receive this information through the Update Service.
If you operate or service instruments with different serial prefixes, we strongly recommend that you
join this service immediately to ensure that your manual is kept current.
For more information, refer to the Documentation Update Service reply card included in this manual
or contact:
Hewlett-Packard Company
Product Support Department
24001 E. Mission-TAF C-34
Spokane, WA 99220
(509) 921-4001
Also,
if you join the update service, you can indicate whether you choose to be contacted in the
future about the quality of the documentation you receive. We are constantly trying to provide the
best documentation possible and periodically survey our customers as to their expectations and the
usability of the manuals we provide.
SAFETY CONSIDERATIONS
The Interface is a Safety Class I instrument (that is, provided with a protective earth terminal).
Before operation, look over the Phase Noise Interface and its related documentation to get familiar
with safety markings and instructions. Refer to the Safety Considerations page found at the
beginning of this manual for a summary of the safety information. Safety information that applies
to the specific task at hand (for example, installation) is found in this manual.
22.3
General Information
S
^*~==^C3
Model 11848A Option 301
e. _a
Fuses
50ft Termination
Noise Floor Test Fixture
Cable Assembly; BNC to SMB
H
Adapters, Type-N to BNC
Cables Assemblies; BNC
22.4
Figure 1. Accessories Supplied
Model 11848A Option 301 General Information
ACCESSORIES SUPPLIED
The accessories supplied are pieces of equipment that are shipped with every Interface. The
accessories are shown in Figure 1.
Line Power Cable. The line power cable may be supplied in several plug configurations, depending
on the destination of the original shipment. Refer to PowerService manual.
Fuses.
Fuses with a 0.75Arating for
Vac (HP part number 2110-0012) are supplied. One fuse is factory installed according to the voltage
available in the country of original destination. Refer to Power Requirements in the Installation of
this Service manual.
HP 3048A Option 301 Software and Manual Set. The HP 3048A software and associated manuals
are shipped with the Interface.
HP 3048A Software (HP part number 11838-10002).
HP 11848A Service Manual (HP part number 11848-90004).
HP 3048A Option 301 Installation Guide (HP part number 03048-90043).
HP 3048A Option 301 Operating Manual (HP part number 03048-90042).
115 Vac
(HP part number 2110-0063) and a 0.5A ratingfor 230
Cables
in the Installation section of this
HP 3048A Option 301 System Calibration Manual (HP part number 03048-90041).
HP3048A Option 301 Reference Manual (HP part number 03048-90040).
50fi Termination. This 50fl load is used to terminate the Interface's Spectrum Analyzer output if
no RF spectrum analyzer is available (HP part number 1250-0207).
Adapters, Type-N to BNC. Three adapters are provided for system operation (HP part number
1250-0780).
Cable Assemblies: BNC. Two 30 cm (12 in.) cables are provided for system operation (HP part
number 8120-1838).
Noise Floor Test Fixture. This test fixture is used to run performance tests (HP part number
11848-61032).
Cable Assembly: BNC to SMB. This cable assembly can be used during troubleshooting (HP part
number 08954-60105).
22.5
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