Boonton 92E User manual

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INSTRUCTION MANUAL
MODEL 92E
R.F. MILLIVOLTMETER
BOONTON
ELECTRONICS CORPORATION
Part No. 982012-00A
791 ROUTE 10, RANDOLPH, NJ 07869
TELEPHONE: 201 -584·1077 TWX: 710-986-8215
Printed in U.S.A.
6/85

SAFETY SUMMARY
The following general safety precautions must be observed during all phases of operation and maintenance
of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this
manual violates safety ~tandards of design, manufactun.:. and intended use of the instrument. Boonton
Electronics assumes no liability for the customer\ failure to comply with the~c re4uirement~.
THE INSTRUMENT MlIST BF.. GROUNDED
To minimize shock hazard the instrument chassi:-. and cabinet must be connected lo an electrical ground.
The instrument is equipped with a three conductor. three prong a.c. power cabk. The power cable must
either be plugged into an approved three-contact dectrical outlet or used with a three-contact to a
two-contact adapter with thdgreen) grounding wire firmly connected to an electrical ground at the power
outlet.
DO NOT OPERATE THE INSTRUMENT IN AN EXPLOSIVE ATMOSPHERE.
Do not operate the instrument in the presence of flammable gases or fumes.
KEEP AW AY FROM LIVE CIRCUITS.
Operating personnel must not remove instrument covers. Component replacement and internal adjust-
ments must be made by quailfied maintenance pcrsonnd. Do not replace components with the power cable
connected. Under certain conditions dangerous voltages may exist C\en though the power cable was
removed. therefore; alway~ di~corrncct power and dischargl'. circuih bl'.fore touching thew.
DO NOT SERVICE OR ADJlJST ALONE.
Do not attempt internal service or adjustment unless another person. capable of rendering first aid and
resuscitation, is present.
DO NOT SUBSTITUTE PARTS OR MODIF"Y INSTRUMENT.
Do not install substitute parts or perform any unauthori1ed modification of the insturment. Return the
instrument to Boonton Electronics for repair to ensure that the safct; leatures an: maintained.
SAFETY SYMBOLS.
This safety requirement symbol (located on the rear panel) has heen adopted by tht·
International Elcctrotechnical Commi~~ion. Documrnt 66 (Central Office) J. Para-
graph 5.3, which directs that and imtrumenl he so labeled if. for the correct use ofthe
instrument. it is necessary to refer t\l the imtruction manual. In this case it is
recommended tha\ refen.:ncc he madi: to the inqruction manual when connecting the
instrument to rhe proper power source. Verify that the correct fuse is installed for the
power available. and that the switch on the rear panel is 'ct to the applicahle
operating voltage.
The CAUTION sign denotes a ha1ard. It ca lb at1cntion to an operation procedure,
practice, or the like, which. if not correctly performed or adhered to. could result in
damage to or destruction of part or alt of the eyuipment. Do not proceed bcyond a
CAUTION sign until the indicated conditions art• fully understood and met.
WARNING •
The WARN ING sign denotes a ha1ard. It calls attention to an operation procedure,
I practice, or the like. which. if not correctly performed or adht"red to, could result in
•------
111
injury or loss of life. Do not proceed beyond a WARNING sign until the indicated
conditions are fully understood and met.
f
Indicates dangerous voltages.

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T A B L E 0 F C 0 N T E N T S
SECTION I - GENERAL INFORMATION
Paragraph
1-1
1-2
1-3
1-4
1-5
1-6
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
3-1
3-2
4-1
4-2
4-3
4-4
4-5
4-6
Introduction
Safety Notice
Description
Accessories Furnished ••••••
Options and Accessories Available
Compatibility of Accessories
Specifications •••.•..••••.••
SECTION II
INSTALLATION AND OPERATION
Installation .•.•.•••••.••••.•..••
Operating Controls and Indicators
Safety Requirement Symbol
Initial Operating Procedures
Operating Notes •• , ••••••••
D.C. Output ••.• , .••••••
Low Frequency Measurements
Correction Curves for Models 952003-0lA and 952007-0lA
Interface Operation ..... , ..................•..........
SECTION III - THEORY OF OPERATION
Introduction ••.••.•••..••••.•
Circuits: Detailed Discussion
A..
Sensor
B. Chopper
c.
Amplifier
D.
Demodulator
E.
Driver
F. Clock
......
G.
Ranging
and
Prog r arnm i ng
H.
Shaping
I•
Power Supply
SECTION IV -MAINTENANCE
Introduction ••.••..•
Periodic Calibration
Power Supply Checks
Calibration Check
Calibration Procedure
Troubleshooting •.••••
A. Cover Removal
B. Replacement of R.F.
C. Probe Tests .•••..•
Probes
1.
2.
3.
S.W.R. Measurement
Frequency Response
Swept Frequency Response and S.W.R.
Page
... l-1
.l-1
.l-1
.l-3
.• 1-3
.1-4
.l-4
• • 2-1
••. 2-1
• 2-2
•• 2-2
.2-2
.2-4
•••• 2-5
.2-5
••• 2-6
.1-1
..... 1- 2
•• 1-2
.1-2
.1-2
.1-3
..• 1-3
••• 1- 3
.1-4
.1-4
.1-7
.4-1
••• 4-1
.4-1
••• 4-1
••• 4-2
•• 4-5
.4-5
.4-5
• • 4-5
•• 4-5
••• 4-6
.4-7
i

SECTION V - PARTS LIST
Paragraph
Page
5-1
Introduction
...................................................
•• 5-1
SECTION VI - SCHEMATIC DIAGRAMS
6-1 Schematic Diagrams, Table of Contents •••••••••••••••••••••••••••• 6-1
Figure
1-1
1-2
2-1
2-2
2-3
3-1
3-2
3-3
3-4
3-5
3-6
4-1
4-2
4-3
LIST OF ILLUSTRATIONS
Page
Input Resistance of Model 92001-02A R.F. Probe •••••••••••• •• 1-6
Input Capacitance of Model 92001-02A R.F. Probe ••••••••••••••• 1-7
Assembly of Type N Tee Adapter •••••••••••••••• , , • , , ••••••••• , • , •• 2-3
Correction Curves for Type N Tee Adapters ••••• • ••••••••••••• 2-5
Rear Panel Pin Assignments ••••••••••••••••••••• • •••••••• 2-6
Simplified Block Diagram •••••••••••••••••••••••••••••••• ••••••• 3-1
Block Diagram: Amplifier Section •••••••••••••••••••• .3-3
Block Diagram: Demodulator and Driver ••••••• , • • • • • • • • , •••• , • , • 3-4
Block Diagram: Ranging Circuitry •••••••••••••••• 3-5
Block Diagram: Shaping Section •••••••• ..3-6
Block Diagram: Power Supply ••••••••••••••••• •• 3-8
Adjustment Locations and Descriptions •••••••••••••••••••••••••• 4-3
Frequency Response Test Setup • . • • • • • • • • • • • • • • • • , ••••••••• 4-6
Swept Frequency Response Test Setup ••••••••••••••.••••••••••••• 4-8
LIST OF TABLES
Page
Crest Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ................ . 1-7
Table
1-1
2-1
2-2
2-3
2-4
5-1
5-2
Operating Controls, Indicators and Connectors •••••••••••••••• 2-1
Connect ion Recommendations •••••••••• , •••.•• , • • • • • • • • • 2-3
Rear Panel Pins: Unit Loadings and Comments ••••••••••••••• ..2-6
Interface Input Characteristics •••••••••••••••••••••••••••••••.•• 2-7
Applicable Federal Supply Code Numbers for Manufacturers ••••••• 5-1
Replaceable Parts ....................•............•.........•.... 5-2
ii

MODEL 921!
PROBE
iii
• Zl!RO
)
MV d8m
3000 r=
1
+20
1000 r ·1 •1()
aoo l } o
100 r .. J -10
30 r J ·20
10 r l -30
3 r l -40
P~R ~ ~::
•
92E RF Millivoltmeter

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S E C T I 0 N I
GENERAL INFORMATION
1-1. INTRODUCTION.
This instruction manual provides general information, installation and
operating instructions, theory of operations, maintenance instructions,
a parts lists, and schematics for the Model 92E.
SAFETY NOTICE
Although this instrument has been designed in accordance with
international safety standards, general safety precautions must be
observed during all phases of operation and maintenance of the
instrument. Failure to comply with the precautions listed in the
Safety Summary located in the front of this manual could result in
serious injury or death. Service and adjustment should be per-
formed only by qualified service personnel.
1-2. DESCRIPTION
A. General. The 92E R.F. Millivoltmeter provides an accurate readout of
measurements from the low radio frequencies to the gigahertz region, over a
voltage range of 200 µV to 3 volts.* It is a programmable, solid state
instrument of high sensitivity and accuracy, characterized by high input
impedance (see Figures 1-1 and 1-2), excellent stability, and low noise.
The 92E exhibits true r.m.s. response for input signals up to 30 millivolts
gradually approaching peak-to-peak above this level.t The meter, however,
is calibrated to indicate r.m.s. of a sine wave above 30 mv.
Input and output connections for external control and readout are provided
by a 22 pin card edge connector at the rear of the instrument.
A linear d.c. output, the level of which is proportional to the r.f. input
voltage, is also provided at a rear connector. This d.c. output may be
used to drive a recorder, a remote indicator, or other analog devices.
The instrument is sensitive, accurate, sturdily constructed, and protected
against overloads. It will perform over extended periods of time without
failure or need for recalibration. It is packaged as a compact bench in-
strument that can be mounted easily in a standard 19 inch rack, us an
optional rack mounting kit.
B. Accessories Supplied. Standard accessories supplied with the Model 92E
include one each of the following:
Model 95200l-02A R.F. Probe with low noise cable and connector.
Model 952002-0lA 50 Ohm BNC Adapter.
Model 952004-0lA Probe Tip (removable), with grounding clip lead.
C. Frequency Capability. The calibrated frequency range of the Model 92E
extends from 10 kHz to 1.2 GHz, with uncalibrated response to beyond 8 GHz.
Relative accuracy* above 1.2 GHz is typically ±0.5 dB.
A
952002-0lA, 50 Ohm BNC Adapter, is supplied as a standard accessory with
the instrument for 50 ohm voltage measurements up to 1.2 GHz.
For through line voltage measurements the optional accessory 952003-0lA Tee
Adapter is recommended. It is designed to compensate for the r.f. probe
*To 300 v, up to 700 MHz, with accessory 100:1 divider.
tTo 3 V, up to 700 MHz, with accessory 100:1 divider.
1-1

§1.2, Continued.
capacitance and to present a good s.w.r. (better than 1.15) up to 1.2 GHz.
It may be used in conjunction with the Model 952028-0lA 50 Ohm Load for
terminated voltage measurements. In a coaxial line its insertion loss is
low: however, a graph (Figure 2-2) is supplied, showing loss vs. frequency.
For lower frequency measurements, the Model 91-4C R.F. Probe is available
as an optional accessory. Its frequency range is 1 kHz to 250 MHz.
D. Voltage Capability. The voltmeter has eight ranges, from 1 mv, f.s.,
to 3 v, f.s., arranged in a 1-3-10 sequence. No attenuator attachments are
required for measurements up to 3 v. While this range is ample for most
radio frequency voltage measurements, the capability of the instrument can
be increased to 300 V (up to 700 MHz), by using an optional accessory, the
high impedance 100:1 Voltage Divider. Use of this 100:1 Voltage Divider
also increases the input resistance by a factor of 1000 to 3000, depending
upon the input level.
E. True R.M.s. Response. The Model 92E provides true r.m.s. response for
signal inputs below approximately 30 mV (below 3 v, up to 700 MHz, with the
100:1 Voltage Divider). As the input level increases, the waveform response
gradually approaches peak-to-peak, calibrated on the indicator in r.m.s.
F. Low Noise. The Model 92E has been designed and constructed to hold
noise from all sources to a minimum. The probe cable is of special low
noise design~ a vigorous flexing causes only momentary, minor deflections
of the meter on the most sensitive range. The probe itself is insensitive
to shock or to vibration.
Amplification takes place at 94 Hz, reducing susceptibility to any 50 or 60
Hz line frequency related fields. The input signals from the probe are
converted into 94 Hz signals by a solid state chopper.
G. Minimal zero Adjustment. zero adjustment is not required on the upper
five sensitivity ranges of the voltmeter. For measurements on the lower
three ranges, the ZERO control is adjusted on the most sensitive range
before operation. Only infrequent checking will be required during the
course of subsequent measurements.
H. D.C. Output. The Model 92E provides a linear d.c. output whose current
capability of 1 mA into 1000 ohms is extremely stable. When used as part
of an automatic test system, the fast response of the instrument's d.c.
output to an input step function allows many tests per unit time.
For system or external requirements, all input and output connections for
the 92E are made at the card edge connector at the rear of the instrument.
(See §2-9 for receptacle connections.)
1-3. ACCESSORIES FURNISHED
A. Model 952001-02A, R.F. Probe. Probe with low noise cable and connector
assembly for measurements from 10 kHz to 1. 2 GHz; see Figures 1-1 and 1-2
for input resistance and capacitance.
B. Model 952004-0lA, Probe Tip. Removable probe tip with grounding clip
lead; for use up to approximately 100 MHz.
c. Model 952002-0lA, 50 Q BNC Adapter. used for measurements up to 1.2
GHz in a 50 ohm system.
*Relative accuracy refers to the differential between two measured levels
without regard to the absolute accuracy of either measurement. A meas-
urement of a 100 mV signal at 8 GHz may indicate 20 mv on the meter:
then a 50 mv signal, at that same frequency, will be indicated as 10 mv,
within about 0.5 dB (5.9%).
1-2

1-4. OPTIONS AND ACCESSORIES AVAILABLE
option -04:
Option -06:
Option -08:
Option -12:
dBV scale uppermost.
75 n dBm scale uppermost.
Rear signal input.
dBmV scale uppermost.
Accessory 91-4C: Special 1 kHz to 250 MHz R.P. Probe. Low-frequency probe
for measurements ranging from 1 kHz to 250 MHzi input resistance is essen-
tially the same as that of the Model 952001-02A Probe (see §l-3A).
Accessory 91-16A: Unterminated N Adapter. May be used with all probes.
used for coaxial connection up to approximately 100 MHz, or to 400 MHz when
fed from a 50 ohm source in an electrically short system.
Accessory 950002-0lB: Single Rack-Mounting Kit. Kit for mounting one 92E
as one half of a module in a standard 19 inch rack.
Accessory 950030-0lA: Double Rack-Mounting Kit. Kit for mounting two
92E's side by side in a standard 19 inch rack.
Accessory 952003-0lA: 50 n Tee Adapter. Type N Tee connectori used with
Model 952028-0lA termination, it permits connection into a 50 ohm line.
See Figure 2-2 for insertion loss vs. frequency.
Accessory 952005-0lA: 100:1 Voltage Divider. Attenuates input signal by a
factor of 100 ±(1 + fMHz/200)%, permitting measurements up to 300 V, and
extending the r.m.s. measuring range to 3 V; also increases input
resistance by a factor of 1000 to 3000, depending upon input level.
Operates from 50 kHz to 700 MHz. Maximum input potential, 1000 V, d.c.
plus peak a.c.
Accessory 952006-0lA: 75 O BNC Adapter. Used for measurements up to 500
MHz in a 75 ohm system.
Accessory 952007-0lA: 75 n Tee Adapter. Type N Tee connector; used with
Model 952029-0lA termination, it permits connection into a 75 ohm line.
See Figure 2-2 for insertion loss vs. frequency.
Accessory 952008-0lA: Unterminated BNC Adapter (Female). Used for coaxial
connection up to approximately 100 MHz, or to 400 MHz when fed from a 50
ohm source in an electrically short system.
Accessory 952028-0lA: 50 n Termination. Type N 50 ohm termination for use
with Tee connector.
Accessory 952029-0lA: 75 n Termination. Type N 75 ohm termination for use
with Tee connector.
Accessory 952011-0lA: Accessory Kit, 50 n. Kit contains the following
above mentioned items: 952008-0lA, unterminated BNC adapter (F);
952005-0lA, 100:1 voltage divider; 952003-0lA, 50 O Tee adapter;
952028-0lA, 50 n termination; Model 952013-0lA, Storage Case {case for pro-
tecting and storing kit accessories).
Accessory 952012-0lA: Accessory Kit, 75 n. Contains the following above-
mentioned items; 952008, unterminated BNC adapter; 952005, 100:1 divider;
952007, 75 ohm Tee adapter; 952015, type N 75 ohm termination; and 952013
storage case.
1-5. COMPATIBILITY OF ACCESSORIES
Accessory models 952002-0lB - 952029-0lA, described above, appear similar
to some older accessories with model numbers type 91-xx. (The newer
accessories have black printing on a silver colored background; the older
accessories have silver colored printing on a black background.)
1-3

The 952001-02A R.F. Probe can be used with these older accessories.
However, the frequency dependent specifications given in this manual for
the use of the 952001-02A R.F. Probe in combination with an accessory
apply ONLY to its use with the newer accessories.
1-6. SPECIFICATIONS
VOLTAGE RANGE:
FULL~SCALF, VOLTAGE RANGE:
dBm RANGE:
FREQUENCY RANGE:
200 µV to 3 V (300 V up to 700 MHz with
accessory 100:1 voltage divider). Lowest
detectable voltage is approximately 100 µV.
I, 3, IO, 30, 100, 300, 1000, and 3000 mv.
-61 to +23 dBm (+63 dBm up to 700 MHz with
optional accessory, 100:1 Voltage Divider).
10 kHz to l.2 GHz (uncalibrated response to
approximately 8 GHz).
ACCURACY: The maximum uncertainty is the sum of the uncertainties given in
sections A, B, and c.
Al. Basic Uncertainty, Voltage
yol tage Level mV
200 µV - 3000 mV
1% f.s.
A2. Basic Uncertainty, dBm
1-4

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-
§1-6, Continued.
B. Frequency Effect
(50 ohm measurements, using Model 952001-02A Probe with Model
952002-018 BNC Adapter or terminated Model 952003 Type N Tee
Adapter.)
Frequency
mV
-----1
dBm ·
------
1
MHz
(Cal.
frequency)
0 0
10 kHz -
100 MHz
1%
rdg.
0.09 dB
100
MHz
-1
GHz 3%
rdg. 0.27 dB
1
GHz
-
1. 2
GHz
10%
rdg. 0.92
dB
--------
S.W.R.: 1.05 to 300 MHz; 1.10 to 1 GHz;
1.15 to 1.2 GHz.
c.
Temperature Effect, at 1 MHz.
Temperature
Range
21°C
to
25°C
18°C
to
30°C
10°C
to
40°C
0°C
to
55°C
METER:
METER UNREST:
(1 mV f.s. range, only)
R.F.I.:
POWER SENSITIVITY:
WAVEFORM RESPONSE:
CREST FACTOR:
INPUT IMPEDANCE:
mv Ranges
dBm Ranges
Instrument R.F.Probe
Inst rument
0 0 0
-----15----
0.2%
rdg.
1%
0.5% rdg. 5%
1%
rdg. 12.5%
-
rdg.
o.
rdg. 0.
rdg.
o.
02 dB
04 dB
09 dB
0. 09 dB
0.45 dB
1.16 dB
4l/2-inch taut-band
Two linear voltage scales:
0 to 3: 0.05 per division
0 to 10; 0.1 per division
One logarithmic dBm scale:
-10 to +3; 0.2 per division, max.
Indicated Voltage
Above 600 µV
300 JJV to 600 µV
200 JJV to 300 JJV
Unrest
< 1% f.s.
< 2% f. s.
< 5% f. s.
There is no detectable radiated or conducted
leakage from the instrument or the probe.
800 pW, minimum measurable power in 50 ohms,
Minimum detectable power in 50 ohms is 200 pW.
True r.m.s. response for input levels up to 30
mV (3 volts to 700 MHz us,ing the 100:1 Voltage
Divider), with transition to peak-to-peak
(calibrated in r.m.s.) at higher levels.
420 to 1.4, depending upon input level (see
Table 1-1).
See Figures 1-1 and 1-2,
1-5

§1-6, Continued.
s.w.R.:
D.C. OUTPUT:
WARM UP:
POWER:
Less than 1.15 to 1.2 GHz (return Loss greater
than 23 dB).
0 to 10 V, d.c., proportional to r.f. input
voltage. Source resistance of 9 kn; will
deliver 1 mA into l kQ load. Full-scale
input step function response time less than
100 ms on 30 mv, f.s., to 3 V, f.s., ranges,
increasing to 1 son the 1 mv, f.s., range.
Warm up period typically 1 min. Adjust ZERO
on 1 mv range when measuring below 30 mV.
100, 120, 220, 240 V ±10%, 50 to 400 Hz.
OPERATING AND STORAGE TEMPERATURES:
A, Operating: 0°C to +55°C
B. Storage: -55°C to +75°C
DIMENSIONS:
132 mm high (without rubber feet) x 211 wide
x 29 2 deep ( 5. 2 in. x 8. 3 x 11. 5) •
WEIGHT:
Net 3.2 kg (7 lbs).
IOM
830363
INPUT RESISTANCE OF BEC RF Pl!OllES
!!M
i
211
3V
"'
1111
:I
:J:
~
l.IJ
u
5001(
z
~
"'
;;;
.. ....__
IV
.....
--
' ........
\.
300mV
!'....
"\
..............
'"'
I\
...
a:
I-
2001<
::>
Q.
!:'.
1001<
IOOmV
..,
'\
I\
I\ \
30mV
-.........
\
i\ '
"'
IOmV
...............
~
\ \
lmV
.
--' '
~
....
"
-"\,. ' \
"''\.
\. \ \ \.
501(
... ~ !\.
\. \
!
~
' ' ' \ '
\ \
·~
'
\\\
~'
~'
\\\j
. .
20K
101(
" "
~"
"
"" ' '
\.\. \.
0.2 2 10 20 so
100
200
FREQUENCY (MHz)
*Curves extend down to 10 kHz without change,
Figure 1-1. Input Resistance of Model 952001-02A R.F. Probe as a Function
of Input Level and Frequency
1-6

Sl-6, Continued.
Ii.
0.
-
w
(.)
z
Cl
I-
-
u
Cl
Q.
Cl
(.)
Table 1-1. Crest Factors
VOLTAGE
RANGES
(mV) 1 3
10
30
100* 300* 1000* 3000*
CREST 420 to
70 to
21
to 7 to 420
to 70 to 21 to 7 to
FACTO Rt
42
14 4.2 1.4
42 14 4.2 1.4
*With accessory 100:1 Voltage Divider, Model 952005-0lA.
tMaximum permissible ratio of peak-to-r.m.s value of voltage.
831277
2.0
1.0
o.._~~~~~--.___ ____ ...._ ______ _._~-----------'----- ....... ---- __ __., ____________ _,
10 30 50 100 300 &00 1000 3000
RF INPUT VOLTAGE ( mV)
Figure 1-2. Input Capacitance vs. Input Level,
Model 952001-02A R.F. Probe
1-7

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-
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S E C T I 0 N
II
INSTALLATION & OPERATION
2-1. INSTALLATION
The Model 92E has been inspected and tested at the Factory before packing,
and it is shipped ready for operation. If there is any indication of ship-
ping damage, immediately notify the carrier before attempting to put the
instrument into operation.
2-2. OPERATING CONTROLS AND INDICATORS
All controls, indicators and connectors used during operation of the 92E
are described in Table 2-1, below.
Table 2-1. Operating Controls, Indicators, and Connectors
ITEM FUNCTION
-----
PWR OFF Switch Depressing this switch
turns the
92E
"off".
-----
FULL SCALE Depressing any full scale range
pushbutton will
Pushbuttons
turn
"on"
the
92E
and
select
the operating
range.
--------
LED
This
red
light emitting
diode
is
lit
when
the
92E
Indicator
is turned
"on".
I
Meter
Taut-band
meter with
two
linear voltage
scales and
one logarathmic dBm scale.
i
PROBE Jack The
probe
cable
connects
to
the
92E
through
this
jack. Always
check that the knurled ferrule nut
of the probe-cable connection is tightened.
-----·----
ZERO
Control This control
is
used to
"zero"
the 92E on its
three most sensitive ranges.
Fuse Holder
The fuse
holder
should
have installed in
it
one of
(Rear Panel) the following fuses:
0.2A, for 100, 120
V;
0.1 A, for 220,
240 v.
----
Slide
Switches Switches
are to be set to
100, 120, 220,
or 240
v,
(Rear
Panel) according to the available line voltage. (Be sure
that
the proper
fuse is
installed.)
Analog
Output A d.c.
voltage proportional
to the meter
reading
(Rear
Panel)
is available
at
these terminals.
-------
REMOTE CONNECTIONS
The
card
edge plug is intended for use with an
(Rear Panel) Amphenol 225-22221-101 connector, or equivalent.
See Table 2-3 for
pin designations.
2-1

2-3. SAFETY REQUIREMENT SYMBOL
This safety requirement symbol (on the rear panel)
has been adopted by the International Electrotech-
nical Commission, Document 66 {Central Office) 3,
Paragraph 5.3, which directs that an instrument be so
labeled if, for the correct use of the instrument, it
is necessary to refer to the instruction manual. In
this case it is recommended that reference be made to
the instruction manual when connecting the instrument
to the proper power source. Verify that the correct
~use is installed for the power available, and that
the switch on the rear panel is set to the applicable
operating voltage.
2-4. INITIAL OPERATING PROCEDURES
A. Be sure that the serial number of the probe to be used is the same
as that of the voltmeter. (Each instrument is calibrated for its par-
ticular r.f. probe.) use of a probe other than that for which the instru-
ment was calibrated may result in measurement errors.
B. Connect the probe cable to the PROBE jack on the front panel.
c. Check the setting of the power switch on the rear panel to be sure
that it is set to the proper position for the line voltage in use.
D. Plug the instrument's power cable into a power receptacle. Press
any Full Scale Range pushbutton to turn the instrument on.
E. Press the 1 mV range pushbutton; the panel meter pointer should rest on
zero. If it does not, use the ZERO control to set the meter to zero. (This
adjustment will hold for the other ranges.) The instrument is now ready
for use. (See §2-5E.)
2-5. OPERATING NOTES
While using the Model 92E is a direct and straight forward process, there
are certain precautions and procedures which MUST be observed to obtain
satisfactory results.
A. Overload Limits. The 952001-02A R.F. Probe supplied with the instru-
ment is-Overload-protected to 10 v, a.c., and to 400 volts, d.c ..
EXCEEDING THESE LIMITS MAY RESULT IN PERMANENT DAMAGE TO THE PROBE,
~--~---~---~~----
The 952002-0lA 50 ohm adapter should not be subjected to continuous
overload of more than 3 volts [d.c, + (a.c., r.m.s.)], to avoid excessive
heating of the terminating resistor.
Where voltages above these limits are likely to be encountered, the
952005-0lA 100:1 Voltage Divider is required. Maximum rating oE the
Voltage Divider is 1000 volts, d.c. + peak a.c.
B. Connection for Measurements below 100 MHz, The R.F. Probe supplied with
the 92E is equipped with a detachable tip and ground lead. For signal meas-
urements below approximately 100 MHz, this tip provides a convenient means
for both signal and ground connection.
c. Connection for Measurements above 100 MHz. For frequencies above 100
MHz, the probe tip should NOT be used with the Model 92E. Connection should
be made directly to the probe's center contact, with the ground connection
kept as short as possible.
The connection recommendations outlined in Table 2-2 should be followed in
order to maintain the specified accuracy.
2-2

Table 2-2. Connection Recommendations
FREQUENCY SIGNAL CONNECTION
Up to 100 MHz
100 to 250 MHz
250 MHz - 1.2 GHz
Probe with tip and ground lead,
or with Model 952002-0lA (supplied)
Probe with Model 952003-0lA/952028-0lA (optional)
Probe without tip, or probe with
Model 952002-0lA (supplied)
Probe with Model 952003-0lA/952028-0lA (optional)
Probe with Model 952002-0lA (supplied)
Probe with Model 952003-0lA/952028-0lA (optional)
RF PROBE
8303~4
/
Figure 2-1.
Assembly of Type N Tee Adapter
2-3

§2-5, Continued.
o. Low Level Measurement. The voltmeter will provide reliable, reprodu-
cible measurements of signal levels as low as 200 microvolts.
Preliminary zero adjustment is essential when using the lowest range scale
to achieve the specified accuracy, and it is strongly recommended for all
ranges up to 30 mv.
E. Making the zero Adjustment. When the instrument is to be used on the
l mV range, the following zero adjustment procedure should be followed.
l. Set the FULL SCALE range selector to the l mv position.
2. Be sure that no voltage is applied to the probe, and that it is
adequately shielded from local fields. This can be done by par-
tially unscrewing the probe cap until the tip just breaks contact
with the internal connector, leaving the metal shell engaged with
the body threads. Alternatively, the probe tip can be removed and
the 50 ohm termination (Model 952002-0lA) mounted in its place.
3. Adjust the ZERO control to bring the meter reading to zero. Noise
may cause the reading to fluctuate. If so, adjust the ZERO control
so that the reading averages zero.
F. Signal Overload on 1 mV Range. on the most sensitive (1 mV) range, the
application of a large a.c. signal overloads the amplifier and a short time
is required for the high impedance input circuit to discharge. This effect
is significant for signals above approximately 100 millivolts. Typically,
application of a 1 volt signal will require a recovery time of about thirty
seconds before subsequent measurements should be made on the 1 mV range. It
should be noted, however, that such overloads cause no damage to the equip-
ment as long as they are within the limits outlined in §2-5A.
G. Temperature Effects. Over the range of 21°C to 25°C (70°F to 77°F),
temperature effects for the Model 92E and the Model 950001 R.F. Probe are
sensibly zero. Outside of these limits, inaccuracies can be expected as
described in the Specifications section (see §l-6C). However, no permanent
change in probe characteristics will result from exposure to any reasonable
high or low temperature.
Inaccuracies of measurement resulting from temperature effects may occur
shortly after soldering to the probe tip, or when measuring with the probe
close to heat sources such as resistors, heat sinks, vacuum tubes, etc.
When making low level measurements (below approximately 2 millivolts) it is
important to make sure that the probe has attained a uniform temperature
throughout its body. A temperature gradient between the inside and the
outside of the probe can generate a small thermal voltage that may add to
the d.c. output of the detector diodes.
H. Hum, Noise and Spurious Pick-up. When measuring low level signals,
precautions should always be taken to avoid the possibility of errors of
measurement resulting from hum, noise or stray r.f. pick-up. Although all
low frequency hum and noise are attenuated at the input, it is still pos-
sible for unwanted high level signals to cause errors. In some cases it
may be necessary to provide extra shielding around the probe connections to
reduce stray pick-up. Typical sources of spurious radiation are: induction
or dielectric heating units, diathermy machines, local radio transmitters,
and grid dip meters.
2-6. D.C. OUTPUT
The d.c. output provided at the rear panel binding posts is a linear func-
tion (typically within 1%) of the input level, as long as the input signal
is greater than 20% of full scale. The polarity of the d.c. output is
positive with respect to the instrument ground, the negative d.c. output
terminal being at ground potential. The output resistance is 9 kn.
2-4

2-7. LOW FREQUENCY MEASUREMENTS
The 952001-02A R.F. Probe supplied with the 92E provides measurements
within the specified accuracy from 10 kHz to 1.2 GHz. For measurements at
lower frequencies the Model 91-4C R.F. Probe is available. It operates
over a frequency range from 1 kHz to 250 MHz.
NOTE:
After installing the 91-4C R.F. Probe, the Model 92E MUST BE checked
for accuracy of calibration. The voltmeter must be recalibrated, if it is
required. (See §4-4 and §4-5.)
2-8. CORRECTION CURVES FOR MODELS 952003-0lA AND 952007-0lA
Use the curves of Figure 2-2 to make corrections for transmission loss when
using the Type N 50 n or 75 n Tee Adapters.
ID
"'O
I
+2
~ +I
0
_J
:fillli
CORRECTION FOR INSERTION LOSS
I
831341
952003
,,./
lo~
"'"952007
-
-~
__ ..
lo
..
.. ..
_ ..
0
300
500
700 1000 1500 2000
FREQUENCY -MHz
NOTES:
1) The Insertion Loss shown is that which exists
between the input and output ports of the Tee.
2) The R.F. Millivoltmeter measures the input
voltage of the Tee.
3) Therefore, if the output voltage of the Tee is
to be determined, subtract the Insertion Loss
determined from the graph from the value that
is indicated on the R.F. Millivoltmeter.
4) Do not use the correction if terminated measure-
ments are required (i.e., measurements with Model
952028-0lA or Model 952029-0lA terminations installed
on the output port of the Tee).
Figure 2-2. Correction Curves for Type N Tee Adapters
Models 952003-0lA (50 O), and 952007-0lA (75 O)
2-5

2.9
INTERFACE
OPERATION
Remote
programming
is
accomplished
by
simultaneously
shorting
to
common
the
Manual
Disable
and
the
appropriate
range
lines
on
the
card
edge
connector
located
at
the
rear
of
the
92E.
(In
effect,
when
Manual
Disable
is
brought
to
common,
the
front
panel
switches
are
disconnected.)
A
pictorial
presentation
of
the
rear
panel
programming
inputs
and
data
out-
put
connections
is
given
in
Figure
2-3.
Table
2-3
provides
additional
data
on
these
connections.
Pin
DATA
OUTPUT
AND
EXTERNAL
PROGRAMMING
PIN ASSIGNMENTS
D
PROGRAMMING
INPUT:
GROUND FOR
COMMAND
0
DATA
OUTPUT:
DO
NOT GROUND
OR
INTERCONNECT-MAY
CAUSE DAMAGE.
LtJ
..J
(!)
II)
RANGE
SELECT
0
<(
..J
z
(/)
, '
<(
0
mV
z.
:::!:
0
<(
:::E
z 0 0
0
0
<(
0
0
0 0
0 0
0
c
0
:::E
,..,
Q
I"')
2
,..,
2,..,
-
2 3 © 5
6
[?J
8
[!]§]QD@@]~~~
17
18
19
20
21
22
A
8
c
D E F H J K L
M N p
R
s
T
u v w
x y
z
830820
Figure
2-3.
Rear
Panel
Pin
Assignments
Table
2-3.
Rear
Panel
Pins:
Unit
Loadings
and
Comments
No.
Function
Comment
Unit
-
Command
Loading
t-------
--------------
.------------------·-------------
------1---------
7
Man.Disable
Disables
front-panel
range
selection
0
0.1
,__
___
...,.
______________
..
_____________________
,
___
,
____
,
__________
.,._
_____
_,a.--------
16
15
14
13
12
11
10
9
f-----
5
4
2-6
1
mV
range
3
mv "
10
mv
..
30
mv
"
100
mv
..
300
mV
..
1
v
n
3
v "
----
Common
o.c.
Analog
Selects
range,
provided
that
Manual
Disable
has
also
been
selected.
Selecting
more
than
one
range
will
result
in
incorrect
indications.
Range
lines
must
be
de-selected
for
manual
operation.
---·---------------------
Power
line
ground
at
rear
panel.
+10
v
for
full
scale
of
"l"
ranges;
+9.5
V
for
"3"
ranges.
0
0
0
0
0
0
0
0
-------
N/A
N/A
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
----·----
N/A
N/A

§2-9, Continued.
A. Input Characteristic~. Interface input characteristics are given in
Table 2-4.
Table 2-4. Interface Input Characteristics
·-··
TTL Logic
Voltage Cu rent per
Series Level Level
Unit Load
-
---
0
±0.7
v
±1.6 mA*
Standard
Power
54/74
1 2.4
to
5.25 v 40 µA
*The "-" current indicates current out of the input (the external command
device must sink this current). A standard power (Series 54/74) TTL output
will sink and source 10 unit loads.
B. rneut Pull-ue. All input terminals have internal pull-up. The current
sourced by this pull-up when the input is brought to a logic level 0 is in-
cluded in the loading shown in the "Unit Loading" column of Table 2-3.
c. o.c. Analog outeut.
1. Polarity: positive with respect to instrument ground. (The negative
D,C. Analog Output terminal is at ground potential.)
2. Source Resistance: 9 kO.
2-7

-
S E C T I 0 N III
THEORY OF OPERATION
3-1. INTRODUCTION
For this discussion, refer to Figure 3-1, a block diagram of the Model 92E.
The r.f. voltage to be measured by the 92E is applied to a sensor, which
converts the r.f. voltage to a proportional d.c. voltage. The output volt-
age from the sensor ranges from a fraction of a millivolt to volts, as a
function of the input voltage level to the sensor. To reduce the effects
of drift and residuals at very low levels, the d.c. output voltage of the
sensor is applied to a solid state chopper, which converts the d.c. voltage
to a 94 Hz square wave with an amplitude proportional to the d.c. voltage.
The drive signals for the chopper are provided from the analog section,
The analog section provides amplification, ranging, and demodulation of the
94-Hz square-wave signal supplied from the chopper. Ranging is performed
manually by means of eight pushbuttons on the front panel; remote ranging
is available by means of rear panel programming connectors. The analog
section also receives a 752 Hz clock signal from the clock section; the
chopper and demodulator drive signals are derived from this clock signal by
frequency divider circuits in the analog section. The d.c. output voltage
of the analog section is supplied to the shaping section, where the ampli-
fied and demodulated d.c. voltage is converted to a linear voltage used for
driving the meter and the analog output. {As noted in §l.2E, the probe's
output is inherently non-linear before shaping; it is true r.m.s. on the
lower ranges, and peak-to-peak on the higher ranges,)
r.f. J
INPUT
PROBE CHOPPER DEMODULATOR
CLOCK DR IVER
RANGE
PUSHBUTTONS------
RANGING
EXT.
PROGRAMMING------.,.;
a.c.
LINE
SHAPING
831333
d. c. ANALOG
Figure 3-1. Simplified Block Diagram
Operating power for the Model 92E circuits is provided by the power supply.
Line voltages of 100, 120, 220, or 240 volts, ±10%, may be applied to the
power transformer. Switches on the rear panel of the instrument allow the
switching of primary winding connections in order to accomodate the various
input voltages. The secondary windings of the power transformer furnish
power to rectifier regulator circuits that develop regulated +5, -5, +15,
and -15 volts for operation of the other circuits in the instrument.
3-1