Tektronix 1401 User manual

INSTRUCTION
MANUAL
1401
Serial
Number
02018
SPECTRUM
ANALYZER
MODULE
Tektronix , Inc. ● P. O. Box 500 Beaverton , Oregon 97005 Phone [phone]
Phone [phone] Cables : Tektronix
070-1071-00
1070

arou
WARRANTY
All
Tektronix
instruments are
warranted
against
defective
materials and
workmanship
for
one year .
Tektronix
transformers
,
manufactured in our
plant
,
are
warranted for the
life of the
instrument .
Any
questions
with
respect to the
warranty ,
mentioned
above
should be
taken up
with
your
Tektronix
Field
Engineer
or
Representative
.
All
requests for repairs
and
replacement parts
should be
directed
to the
Tektronix
Field
Office or
representative in your area . This procedure will assure
you the fastest possible service . Please include the
instrument Type ( or Part Number ) and Serial or
Model
Number
with all
requests
for
parts or
service .
Specifications and price
change
privileges reserved .
Copyright
©
1970 by
Tektronix , Inc. ,
Beaverton
,
Oregon . Printed in the United States of America . All
rights
reserved
.
Contents
of
this
publication
may not
be
reproduced in any
form
without
permission of the
copyright
owner
.
U.S.A. and foreign Tektronix products covered
by U.S. and
foreign
patents
and /
or
patents
pending
.
43

TABLE
OF
CONTENTS
SECTION 1
SPECIFICATIONS
Introduction
Electrical Characteristics
Power
Requirements
SECTION 2
SECTION
3
Environmental Characteristics
Physical
Characteristics
OPERATING
INSTRUCTIONS
Accessories
for the 1401
Installation
Power Source and Application
Battery
Care
Function of Controls and Connectors
First Time Operation
General
Operating Information
Signal
Application
Resolution and Frequency Span
Using
the
Video
Filter
Selecting
Sweep
Rates
Triggering
the
Sweep
Externally
or
Using an
External
Sweep
Source
Sweeping the
Companion
Oscilloscope
422/1401
Compatibility
453/1401 and 454/1401 Compatibility
Alternate Procedure for Most Oscilloscopes
CIRCUIT DESCRIPTION
Introduction and Block Diagram Description
Detailed Circuit Description
RF
Section
IF Circuit
Logarithmic
Amplifier
,
Linear
Amplifier
and Video
Circuits
Sweep
Generator
Frequency
Span and
Center
Frequency
Marker
Generator
Sweep
Shaper
Power
Pack
Page
1-1
1-1
1-2
1-2
1-3
2-1
2-1
2-1
2-3
2-5
2-8
2-10
2-10
2-10
2-11
2-11
2-11
2-12
2-13
2-13
2-13
3-1
3-3
3-3
3-4
3-5
3-5
3-5
3-7
3-8
3-9
3-12
1401
i

1401
ii
SECTION 4
SECTION 5
SECTION
6
TABLE OF CONTENTS ( cont )
MAINTENANCE
Access
to the
Interior
Preventive
Maintenance
Procedure
Troubleshooting
Corrective
Maintenance
Procedures
Obtaining
Parts
Soldering
Power
Pack Servicing
Replacing
Circuits
Boards
or
Assemblies
Replacing
Square Pins
for
Multi - pin
Connectors
Cam Switch Repair or Replacement
RF Module and Sub - assemblies
Physical Location of Components
PERFORMANCE
CHECK
Introduction , History Information , and Equipment Require
ments for
the
Performance
Check
Short Form Procedure
General Information
Procedure
Preliminary
Battery Charge Level Indicator Operation
Center Frequency Range and Accuracy
Frequency
Span
Resolution
Bandwidth
Incidental FM
Video
Filter Operation
Dynamic Range
of Display
Functions
RF Attenuator dB Selector Check
Video Output Level
Sensitivity
Display
Flatness
Spurious Response
Intermodulation Distortion
Sweep Rate Range and Sweep Output Amplitude
External
Trigger
Operation
External
Sweep
Voltage
In
Operation
CALIBRATION ADJUSTMENT PROCEDURE
Introduction ,
History
Information
and
Equipment
Required
Short Form Procedure
Preliminary Procedure
Set Battery Charge Current
Check
/
Adjust Power
Regulation
Voltages
Detailed Alignment Procedure of RF and IF Circuits
General Alignment of RF and IF Sections
Frequency Span and Center Frequency Accuracy Adjustments
Adjustment
of Linearity
Gain
Page
4-1
4-1
4-2
4-7
4-7
4-7
4-7
4-9
4-10
4-11
4-11
4-11
5-1
5-1
5-3
5-4
5-4
5-5
5-6
5-7
5-7
5-8
5-8
5-9
5-9
5-9
5-10
5-10
5-10
5-10
5-11
5-12
6-1
6-1
6-1
6-2
6-3
6-3
6-6
6-7
6-11

SECTION
7
TABLE
OF
CONTENTS (
cont
)
SECTION
9
ELECTRICAL
PARTS
LIST
Abbreviations
and
Symbols
Parts
Ordering
Information
Index of
Electrical
Parts
List
Electrical
Parts
List
SECTION 8
DIAGRAMS ,
CIRCUIT
BOARDS ,
MECHANICAL
AND
REPACKAGING
PARTS
ILLUSTRATIONS
Symbols
and
Reference
Designators
1401
Waveform
and
Voltage
Information
MECHANICAL
PARTS
LIST
Mechanical
Parts
List
Information
Index of
Mechanical
Parts
Mechanical
Parts List
Accessories
Abbreviations and
symbols used in
this
manual are
based on or
taken directly from
IEEE
Standard 260 "
Standard
Symbols for
Units
" , MIL -
STD - 12B
and
other standards of
the
electronics
industry
.
Change
information , if any , is
located at the rear
of this
manual
.
1401
iii

1401
Com
10
OFF
POWER
20
BATTERY
CHARGE
LEVEL
OF
GAIR
RF
ATTEN
dB
30
40
ON
50
60
VERTICAL
DISPLAY
LOG
LIN
1.500
250
INPUT
500
-30
dBm
MAX
1401
SPECTRUM
ANALYZER
MODULE
1401
TEKTRONIX
SPECTRUM
ANALYZER
MODULE
CENTER
FREQ
MHz
SEARCH
MARKER
FINE
012
/
VIDEO
FILTER
FREE
RUN
OFF
TRIG
IN
RESOLUTION
kHz
EXT
IN
MODE
SWEEP
Fig
. 1-1
. 1401
Spectrum
Analyzer
Module .
1000
100
TEKTRONIX ,
INC .
BEAVERTON
,
OREGON ,
U.S.A.
SLOW
RATE
FREQ
SPAN
MHz /
DIV
VAR
(
CAL IN
)
FAST
0.01.02.05
SEARCH
1
12

SECTION 1
SPECIFICATION
Change information , if any , affecting this section will be found at the rear of the manual .
Introduction
The 1401
Spectrum Analyzer
Module
is
a
compact port
able instrument designed to operate with a Tektronix Type
323 portable oscilloscope so that the two instruments com
prise a portable spectrum analyzer system that can be used
for on - site spectrum surveillance , RFI testing , etc.
The 1401 has a swept front - end which provides a fre
quency span from 1 MHz to 500 MHz . A linear or logarith
mic display is provided . Dynamic range of the logarithmic
display
is at
least 60
dB .
The 1401
will
operate from any one
of three
power
sources ;
internal rechargeable
batteries ,
external ( +6 V
to
16 V ) DC , and AC line . Power consumption is about 4.5
watts DC , and up to 14 watts when powered from an AC
source .
WARNING
When the 1401 is used as a portable instrument , a
common
ground
return to the
signal
source
must be
provided . This insures that measurements are reliable ,
and eliminates any possibility of the instrument case
becoming
elevated to the
potential of the
signal
source
.
The instrument power pack is provided with a three
terminal polarized power receptacle and a three wire line
cord for applying AC to the power pack . The third wire is
directly
connected to the power
pack chassis ,
which is con
nected by
interconnecting
wires to the
1401
chassis . This
grounds the instrument when operating from an AC source
to
protect
operating personnel as
recommended by
national
and international safety codes .
Performance Conditions
The
performance
limits in
this
section are valid with
the
following
conditions
:
Power the instrument from the battery or an external
DC
source
. The
instrument
must have
been
calibrated with
in
an
ambient
temperature
of 20
° C to 30
° C (
Section 5
provides a
description of the
procedure for
checking the
1401 ) . The
instrument must be
operated within an
ambient
temperature of -15 ° C to + 55 ° C , and must be allowed to
warm up for at least 20 minutes after switching the POWER
to ON
position .
ELECTRICAL CHARACTERISTICS
Characteristic
Center
Frequency
Accuracy
FINE Control
Range
Sensitivity
Resolution
Band
width
3
kHz
100 kHz
1000
kHz
Frequency
Span
Calibrated MHz /
Div
Range
with
10
division
display
Accuracy
Linearity
Frequency
Stability
Performance Requirement
1 MHz to 500 MHz , continuously
variable .
+
or
Within
( 5 MHz
+ 5 % of the 1-500
dial
readout ) ,
FINE control at
.
-
1
MHz ,
within
10 %
At
least 100
dBm
-
1401
At
least -90
dBm
At
least -80 dBm
Hz to 500
MHz
10 kHz / Div to 50 MHz / Div in 1 , 2 ,
5
sequence .
Within
10 % of
FREQ
SPAN
MHz
/ Div
selection , with
VARiable
control in CAL position .
Within 10
% with 10
division
dis
play
.
Within 50
kHz , at
+ 20 ° C to
+ 30 ° C
,
over
any 5 minute
interval ,
after
20
minute warmup . Temperature co
efficient less
than 0.5
MHz / ° C
.
1-1

Specification -
1401
ELECTRICAL CHARACTERISTICS ( cont )
Characteristic
Intermodulation
Distortion
Maximum
Input
Power
RF
ATTEN
at
dB
RF
ATTEN at
60 dB
Display
Flatness
Resolution Band
width
Incidental
FM
IF GAIN Control
Range
Dynamic
Range
LOG
Display
VIDEO OUTPUT
External
Trigger
Level
Duration
Frequency
External
Sweep
Level
Performance
Requirement
1-2
Down at least 50 dB .
-30 dBm ( Linear operating limit )
+30 dBm ( Power rating of atten
uator )
Within 3 dB maximum amplitude
variation over the entire frequency
range
.
1000
kHz , 100
kHz , 3 kHz
, within
10 % .
Sweep
Range (
FREE 1
sweep / s
or less to
at least
100
RUN
Mode ) sweeps /
second .
No
more
than 20
kHz at 1
MHz
center
frequency
, to
10
kHz or
less
at 500 MHz
center
frequency .
30
dB
or more
At
least 60 dB
1.2 V for full screen deflection .
+1 V
to
+10 V
peak
At least 100
ns
1
MHz
or
less
to 5 V
with V
corresponding to
Hz frequency and +5 V corres
ponding to 500
MHz .
Maximum
Sweep
100
sweeps
/ second
Rate
Maximum
Input
10
V
Voltage
ELECTRICAL
CHARACTERISTICS
( cont )
Characteristic
RF ATTENuator
Accuracy
Sweep Output
(
FREE RUN
or
EXT TRIG
Mode )
Characteristic
Line
Voltage
Range
Frequency
POWER SOURCE REQUIREMENTS
Power
Consumption
External DC Volt
age
Range
Power
Consump
tion
Battery
Pack
Charge
Time
Operating
Time
( + 20 ° C to + 25 °
charge
temperature
,
+ 20 ° C to + 30 ° C
operating
tem
perature ) .
Characteristic
Performance Requirement
Temperature
to 60
dB in
10 dB
steps
Within (
0.5 dB + 1
% of dB read
ing )
Without
Batteries
5 V ± 0.25 V
Performance
Requirement
90 V to 136 V AC
or
180 V to 272 V AC
48 Hz to 440 Hz
14 watts maximum at 115 V AC
+6 V to
+16 V. Surge
current
requirement is 1
ampere .
4.5 watts maximum
Six
, C size
NiCd
cells
ENVIRONMENTAL
CHARACTERISTICS
16
hours
for
full
charge
At
least
3.5
hours
Performance
Requirement
Non - operating
With Batteries
-40
° C to + 60
° C
-
55 ° C to + 75
° C

ENVIRONMENTAL CHARACTERISTICS ( cont )
Characteristic
Operating
Charging
Altitude
Non -
operating
Operating
Vibration
Operating
Height
Width w / handle
Depth w / panel cover
Depth
w /
handle
Performance
Requirement
-15 ° C to + 55 ° C
° C to + 40 ° C
To 50,000 feet
To 30,000 feet ; maximum ambient
temperature
rating
must be
de
creased 1 ° C per 1000 feet , from
15,000
to 30,000
feet .
15 minutes along each of the 3
major axes , 0.025 inch peak
to - peak displacement ( 4 g's at 55
c / s ) 10 to 55 to 10 c / s in 1 - minute
cycles .
Net
approximate
weight
w /
o
accessories
Domestic shipping weight
Export - packed weight
in .
3-1 /
2
8-1
/ 2
10-5 / 8
13
1401
lb.
≈7 1/2
13
21
Humidity
cm
.
ENVIRONMENTAL CHARACTERISTICS ( cont )
Characteristic
Non -
operating
and
Operating
Electromagnetic
Finish
8.9
21.6
27.0
33.0
kg .
≈3.4
5.9
9.5
in .
3-1 / 2
8-1
/ 2
10-5 /
8
13
lb.
≈7
13
≈21
323
Performance
Requirement
5
cycles ( 120
hours ) to 95 %
relative
humidity
reference
to
MIL
- E
16400F ( Par . 4.5.9 through
4.5.9.5.1 , Class 4 ) .
Meets
radiated interference
require
ments
of MIL
-
1-6181D
and
MIL
-
1-1690C over the range
150
kHz
to one
GHz . (
Instrument
must
be
battery operated . )
PHYSICAL
Specification
-
1401
Front -
panel has an
anodized
finish
;
cabinet
is
made of
vinyl - clad
aluminum .
cm .
8.9
21.6
27.0
33.0
kg .
3.2
5.9
9.5
in .
1401/323
7
9-3 / 8
10-5 / 8
14-5 / 8
lb.
≈14 1/2
~ 22
≈30
cm .
17.8
23.8
27.0
37.2
kg .
≈6.6
≈10.0
13.6
1-3

NOTES
1
1
1

SECTION 2
OPERATING
INSTRUCTIONS
Change information , if any , affecting this section will be found at the rear of the manual .
Introduction
This section of the manual describes installation and
procedures pertinent to operating the 1401. It covers func
tion of
the
controls and
connectors
,
hookup
to
a com
panion
oscilloscope , battery
care ,
operational
procedure
for
familiarization and
some
examples of
instrument appli
cations .
Accessories
Standard accessories that are included with the 1401 are
listed near the back of the manual . The following describes
the purpose of items that are not self explanatory .
Panel Cover . A friction fit keeps this cover over the
front panel during storage or transporting . The cover can be
placed
over the
rear of the 1401
for storage when
the 1401
is in use . The recess in the cover acommodates the acces
sory
pouch strap
, and should not
be used as a
finger grip for
cover
removal .
Accessory Pouch . This pouch grips to the handle pivots
and the cover securing screw at the rear panel . It has suffi
cient capacity to hold the standard accessories , including
the Operators Handbook , with the exception of the
standard
manual and
the
Panel
Cover .
Strap Assembly . The strap is designed to snap into place
for transporting the instrument . It can be used to suspend
the 1401 in front of , or alongside , the operator during use .
The handle can be extended between the operator and the
1401 , to obtain optimum viewing positions .
3 to 2 - Wire Adapter . Grounding is not provided through
the AC power source when the adapter is in use . A separate
grounding
connection
must be
used .
BNC to BNC Cable Assemblies . The two short cables are
used
to
connect the 1401
VIDEO OUTPUT
and the
SWEEP
voltage to the
Vertical
Input and Ext
Horiz Input
of a
companion
oscilloscope .
The 6 foot
coaxial cable
is used to
connect the signal
source to
the RF INPUT
connector on
the 1401 .
1401
Operators Handbook . Designed to fit in your shirt
pocket and use as an on - site reference document . Includes
prime characteristics , operating instructions , and some
applications
.
Installation
The 1401 is designed to use with a portable oscilloscope ,
such as Tektronix Type 323. It can , however , be used with
any
oscilloscope
that has an external
horizontal
input or
access to the horizontal sweep voltage . Interconnections
between the 1401 and companion oscilloscope are illus
trated in Fig . 2-1 along with control settings .
Refer to " Sweeping the Companion Oscilloscope " ,
under General Operating Information for additional infor
mation .
POWER SOURCE AND APPLICATION
The 1401 requires either an internal power pack or an
external ( +6 V to +16 V ) DC source for power . The power
pack consists of a battery and a charging circuit . The
charging circuit operates from AC line voltage , to charge
the
battery or
maintain a given
charge level after
it has been
charged . When fully charged , the battery pack will supply
the 4.5 watts required by the 1401 and maintain this power
output
for
approximately 3.5
hours
operation .
As
previously stated , the
charging circuit in the
power
pack
operates from
either
115
V or 230
V nominal
AC
power
. Slip - on
connectors
, on the power
pack , are
used to
wire the charging circuit for the voltage to be used . Hookup
illustrations
and
instructions
are
given in Fig . 2-2
. Battery
charging occurs whenever AC power is applied to the AC
receptacle on the
power pack .
Charging rate ( FULL
CHG or
TRICKLE CHG ) is selected by a three position switch on
the back panel of the power pack . Usually the battery is
fully charged at the FULL CHG rate , then maintained at
this
charge level
by switching
the selector to
TRICKLE
CHG position . TRICKLE CHG supplies sufficient current
to maintain the battery in full charge condition , plus the
required power to operate the 1401. Battery charging is
described under Battery Care . The 1401 will not operate
from an AC source if the batteries are missing or defective .
2-1

Operating
Instructions
- 1401
5
10
INPUT
2-2
AC
10
GNO
DC
VOLTS
/
DIV
CAL
1
20
OFF
20
OFF
.5
5
DIV
CAL
.01
POWER
BATTERY
CHARGE
LEVEL
POWER
LOW BATT
TYPE 323 OSCILLOSCOPE
BAIN
RF
ATTEN dB
30
40
1401
.02
.05
ON
ON
50
60
1.2 LIN
1.o
0.8
0.6
0.4
Hz
Response
0.2
X 10
VERT
GAIN
PULL
KTANNI
ME
TRUS
ANALYZER
VERTICAL
DISPLAY
LOG
LIN
1-500
Frequency
Marker
500
1401
SPECTRUM
ANALYZE ODULE
INPUT 500
-30 d8m
MAX
1.
Switch
POWER
to
ON
position
,
then adjust
oscilloscope
POSITION
controls
to position
the sweep or
display on the
bottom graticule line with the Hz marker at the zero
graticule line . Adjust the Horizontal Variable control for a 10
division
sweep
.
X 10
HP
AIZ AG
PULL
SONY
TEKTRONIX
TOKYO
,
JAPAN
POSITION
CENTER
FREQ
MHz
SEARCH
MARKER
The battery can be charged with the power pack out of
the
instrument
.
Extra power
packs can
therefore be charged
to
serve
as
spares
if desired
.
The 1401 can also be powered from an external DC
power
source . Set
the power pack
switch to the
EXT DC
position , then connect a +6 V to +16 V DC source to the
banana jacks above the line cord receptacle ( observe polar
ity markings ) , and switch the front panel POWER switch to
ON . The
external
DC
source will not
charge
the
internal
battery , and the 1401 will not operate from the internal
LOG
-0
10
61
"
FINE
ala
20
-30
8/1
\
8
19
/
40
-50
VIDEO
FILTER
FREE
RUN
TRIG
IN
RESOLUTION
kHz
OFF
EXT
IN
FOCUS
20
VARILE
CAL
50
10
2
S.5
Midrange
MODE
TIME
/ DIV
Fig . 2-1A . Front view illustrating control and switch settings .
TRIGGER
2
3
EXT
5
/
HORIZ
VAR
AUTO
1000
SWEEP
TEKTRONIX , INC . , BEAVERTON , OREGON , U.S.A.
SLOW
INTENSITY
5
ms
.2
50
20
/
10
MS
r
INT
TRIG
EXT
TRIG
OR
HORIZ
RATE
FREQ SPAN MHz / DIV
VAR
( CAL IN )
0.01.02.05
SEARCH
FAST
ACLF
REJ
1
AC
AC
DC
2. Set the CENTER FREQ MHz 1-500 control to 500 .
Position the frequency marker ( notch ) behind the 10
division line with the Horizontal Variable control . The
display should be slightly more than 10 divisions with the
Hz marker at the zero division line and the frequency
marker behind the 10 division line .
Note : If the graticule height is other than 6 divisions use
1.2
V
No. div .
WARNING
to determine Volts / Div setting .
battery or an AC source if the selector switch is left in EXT
DC position .
The battery will ,
however ,
charge at full
charge rate if AC power is applied when the switch is at the
EXT
DC
position .
POWER PACK REPLACEMENT
The battery , in the power pack , is capable of deliv
ering enough energy to cause severe burns if it is short
circuited by such items as rings or a watch band .

AC / BATT
A
AC / BATT
EXT
TRIG OR
MORIZ
ATTEN
10X
TRIG IN
OMB
WALT
SWEEP
VOLTAGES
( EVIOUT
OF
AC
POWER
EXT DC
POWER
EXT
BLANK
VERTERPUT
2002
VIL OUT
90-138
OR
180-272V
CHANGE
INSIDE
48-440
MI
14
WATTS
MAX
13
AMPS
MAX
Switching
the
power selector
switch
to the EXT
DC
position reduces this hazard by removing battery volt
age from most of the exposed terminals . Set the
power selector switch to EXT DC position , or remove
rings and watch band before handling the power
pack .
GV
- NV
4
WATTS
MAX
AT
MY
7
AMPS
MAX
AY
6V
115V -
80M
Fig . 2-3 illustrates the procedure required to remove the
power pack
. Replace
the pack
by reversing
the
removal
steps
. Insure
that the wire
color code
matches that
indi
cated on the
terminal
mounting
.
CAL DU
GND
Operating Instructions - 1401
To
signal
source
Fig . 2-1B . Side view to illustrate cable interconnections and switch positions .
WARNING
323
There is
no
common ground
between
the
signal
source
and
the
instrument
unless
this
connection is
made . Without a common ground , measurements are
not
reliable
, and
the 1401 case
can rise to
a dangerous
signal
source
potential
.
BATTERY CARE
1401
The
power pack
uses six sealed
NiCd
batteries . These
cells require
little
maintenance , have high
discharge
rate ,
accept long term overcharing , and operate over a relatively
wide range of temperature . If properly cared for , you can
expect about 500 to 600 charge / discharge cycles before
their capacity drops to about 80 % of specified value . Some
of the more important battery characteristics are described
in the following paragraphs . Battery care information is also
provided , to help obtain maximum operating time between
recharge cycles
.
2-3

Operating
Instructions -
1401
Pas
31
18
MUS
AOEZ
1.
115
V AC
connection
.
Fuse size 0.2
A.
30
1
%
Insulation
on
230
V
pins
230 V
Connection
10
2-4
AOCZ
115 V Connection
3.
Spare
fuse
location .
15
2.
230 V
AC
connection .
Fuse
size 0.1 A.
Insulation on
115 V
pins
Fig . 2-2 . Preparing the 1401 for 115 V or 230 V nominal AC power .
SELF
DISCHARGE
is
a
continuous
process
,
as long as
the
battery
has
any charge
. The rate of
self
discharge
depends on ambient temperature , state of charge , and
impurities in the battery . Self - discharge at 45 ° C is approxi
mately five times greater than at 20 ° C . A fully charged
NiCd cell may lose 10 % to 15 % of full capacity during the
first 24 hour period . This discharge rate decreases to about
0.68
% per day
or 10 %
to 15 % per
month
after
the initial
discharge . To obtain the maximum operating time , the
battery should be fully charged and maintained at this level ,
MODEL
S
Cover
securing
screw
NO PODI
a
. Loosen
securing screw
and pull
dust cover
off .
Pull
power
pack
back and out
of its
mounting
area .
Avoid
bumping
transformer
wires or
circuit
board
against
chassis .
Observe color code when replacing power unit .
115
V terminals
OF
NETWO
We are
SAVE
BEENVI
#O
SAY
ONIONYH
)
300139
344
34
510
11300W
20-6110-910
230 V
terminals
c .
Power
pack .
sout
***
. *** .
Fuse location ; pull
cover
straight
down
to
expose
fuse
;
align
cover
detents
and fuse
mounting
base
when re
placing cover .
Securing
clamp
Grn
on
wht
Wht
Blk on wht
b . Disconnect interconnecting power leads . Release securing
clamp .
Interconnecting
leads
Positioning
lugs
Fuse Cover
31
Fig . 2-3 . Removing or installing the battery power pack .
by
using the
TRICKLE
CHARGE
feature
to
offset self
discharge until the pack is ready to use .
On FULL CHARGE , the power pack delivers a constant
current that is approximately 1/10 the ampere hour rating
of the cells in the battery . This charge rate allows the
battery to be
overcharged
without cell
damage
.
CHARGE
TIME
for the
battery
is
about 14 to
16 hours at the
FULL
CHARGE
rate
.
A

OVERCHARGE is
continued
charging
after
the
cells
have
reached
full
charge .
Short
periods of
overcharging
will
cause
no
problems .
During the
overcharge
period
, the
charge energy is dissipated as heat . If continued for an
extended
period (
over 24
hours ) , it
will dry
the
electrolyte .
TRICKLE
CHARGE
maintains the
battery or cell at
full
charge . It will not recharge the cells , because most of the
current is
used to
recover the
self -
discharge
current
.
Use
TRICKLE CHG to
maintain the full
charge state of the
cells .
OPERATING
TIME
is
a
function of
temperature and
charge state . You can expect about 3.5 hours of operation
under average conditions . The CHARGE LEVEL indicator
on the front
panel is an
expanded
scale
voltmeter
, with the
green sector indicating about 7 1/2 to 6 1/2 volts ( full
charge to 90 % discharge ) . At about 6 1/2 volts , the voltage
starts to decrease rapidly , therefore , after the indicator
moves into the red sector , operation should be terminated
as soon as possible . This reduces the possibility of any cells
becoming reverse charged . Reverse charging occurs when
some cells have more charge than others , and overcome the
weaker cells .
CHARGE BALANCING consists of charging the cells
beyond the period required to bring them up to full charge .
This
balances the charge of
the cells in the
battery , and
reduces the possibility of any cells reverse charging . Once a
month or every 15 charge / discharge cycles , change the
charge time to about 24 hours . Any time a cell is replaced ,
the battery should be overcharged to balance the cells .
Avoid partial charges if possible ; however , if only a
partial charge is practical , about 30 to 45 minutes of opera
tion can be
expected
per
one hour
charge .
STORAGE
temperature for the
batteries may be
between
-40
° C
and + 60 °
C .
Cells can be
stored
either fully
charged or partially charged ; however , self discharge rate
increases
with
temperature , so a
fully
charged
battery will
lose
about 50 %
of its
charge
at
room temperature (
70 ° F ) in
about three
to four
months
. The
battery
pack
should be
recharged , therefore , before it is used , to bring it to full
charge
.
Additional data
regarding
maintenance and
repair of the
power pack and the NiCd cells is furnished in the Mainte
nance
Section .
Handle
The following controls and connectors are accessible at
the
exterior
surfaces of the
1401 and
are
used to
operate
the
instrument ( see Fig . 2-4
) . The names
of these
exterior
controls
and
connectors
,
when
referred
to
in the text are
printed in
upper case
letters so they
are more easily
recognized as belonging to the 1401. Names of the controls
and
connectors for
associated
equipment
,
such as the
com
panion oscilloscope , are printed using initial capital letters .
This policy is followed throughout the manual .
POWER
FUNCTIONS OF
CONTROLS ,
CONNECTORS
AND
INDICATORS
Operating Instructions - 1401
RF ATTEN dB
IF GAIN
BATTERY CHARGE An expanded - scale DC voltmeter to
LEVEL
monitor
battery voltage and charge
level .
When indicator
drops into the
red
zone ,
operation
should be sus
pended
and
the
battery
recharged
.
Operation can continue for about
10 minutes after the indicator
drops into
the red zone ;
however
,
operation beyond this time may
damage the cells . If the indicator
registers in the red zone when an
external DC
source is
used to
power
the unit ,
it
indicates the
source
voltage is about +6.5 V or lower .
INPUT 50 S
320
°
rotation .
Detents
hold
the
handle
in
any one of
the
numerous
positions throughout travel arc .
Detents automatically unlock in
response to rotary pressure on the
handle
.
Front Panel
Two
position slide
switch interrupts
or completes power circuit between
power
pack
and 1401
circuitry .
Does not
affect
battery
charging
circuit
.
Selects
amount
of
signal
attenua
tion
between the
INPUT
connector
and the
1st
mixer .
Provides at least 30 dB of variable
IF
attenuation
.
RF
input
connector .
Input
imped
ance about 50 2. Maximum input
signal level , for
linear
operation
,
with dB RF ATTEN is -30 dBm .
Maximum input signal level with
2-5

Operating
Instructions
—
1401
IF
GAIN
control
LOG
10
2-6
Indicates charge level
of the battery . When
needle moves into red
zone
, battery
should
be
recharged .
OFF
20
POWER
BATTERY
CHARGE
LEVEL
IF
GAM
RF ATTEN dB
30
40
VERTICAL DISPLAY
LIN
50
60
VERTICAL
DISPLAY
LOG
LIN
1-500
INPUT
502
-30
dBm MAX
1401
SPECTRUM
ANALYZER MODULE
CENTER
FREQ
MHz
SEARCH
MARKER
RF
INPUT
connector .
Input level should not
exceed -30 dBM with
RF
ATTEN dB
selector
at
, +30
dBM with
RF
ATTEN dB
selector at
60 .
FINE
210/2
ol
VIDEO
FILTER
RESOLUTION
kHz
FREE
RUN
OFF
the RF ATTEN at 60 dB is +30
dBm
,
which
is the
maximum
power
rating of the attenuator .
TRIG
IN
When depressed , provides a linear
display
.
EXT
IN
When
depressed ,
provides
logarith
mic
display with
dynamic range of
60
dB
.
MODE
SWEEP
1000
100
TEKTRONIX , INC . , BEAVERTON , OREGON , U.S.A.
3
FREQ SPAN MHz / DIV
VAR ( CAL IN )
Battery - EXT DC
Selector
SLOW
RATE
601.02.85
TRIG IN
SEARCH
LOVE
FAST
02
85
1
SWEEP VOLTAGES
VON
50
Fig . 2-4 . Selectors and connectors on the 1401 .
8
PRONI
NE
CENTER FREQ
MHz
ARAGE
MED
POWER
VIDEO
OUT
887
DC
Powe
Push to
unlock
VARIABLE
Frequency
Span control
www
Sweep
rate
control
FREQ
SPAN
selector
a
A
-
MY
*
Mu
TRADE
ME
AN
****
Ground
AC
Power
EXT
DC POWER
1-500 selector is a 10 - turn digital
type
control
that selects
the center
frequency
of the
display .
This
center frequency is calibrated to
the
control readout when
the FINE
control is at the position . The
center frequency is automatically
switched to 250 MHz when the
FREQ SPAN MHz / DIV selector is
switched to the SEARCH position .
A search marker appears on the dis
play , which can be positioned by
the
CENTER
FREQ MHz
control
(
A )

SWEEP Controls
MODE
Selector
SWEEP RATE
FREQ SPAN MHz /
DIV
VAR (
CAL IN
)
to the
frequency
indicated on the
dial
readout .
FINE
control is
a
10 -
turn
dial type
control
that
provides a
fine
adjust
ment of the
center
frequency .
Fre
quency
range of the
control is
with
in ± 1
MHz
of
the
1-500
control
setting .
Selects the
following
sweep
modes
:
FREE
RUN :
A
free
running
sweep
at a rate determined by the RATE
control .
TRIG IN
:
Enables
the
sweep to
be
triggered by a
triggering
signal
applied to the TRIG IN connector
( see
TRIG IN
connector
function
for trigger - signal limitations ) .
EXT
IN :
Enables
an
external
sweep
signal that is applied to the SWEEP
VOLTAGES
connector
to
sweep
the local
oscillator
.
( See
SWEEP
VOLTAGES
connector
function
for
voltage
information ) .
Varies the
internal
sweep
rate from
approximately 1 sweep / second to
about
100
sweeps /
second .
Selects frequency width of the dis
play . Calibrated selections are ; 50
MHz
/ DIV
to 10
KHz / DIV
in a 1 , 2
,
5
sequence
. A
Hz position
pro
vides time
domain
information .
Accuracy , for a 10 division display ,
is
within 10 % of the
selection
when
VARiable
control
is
pushed into
the CAL
detent
.
A
push - on
push
- off
type
control ,
concentric with FREQ SPAN selec
tor
that
locks in ,
when
pushed , to
provide
a
calibrated
frequency
span . When pushed again , the con
trol
unlocks
and
provides
a
contin
uous
variable
frequency
span
between the FREQ SPAN MHz /
DIV selections .
RESOLUTION kHz
VIDEO
FILTER
TRIG
IN
SWEEP
VOLTAGES
VIDEO OUT
Operating Instructions - 1401
Selects
1000
kHz ,
100 kHz or
3
kHz
resolution
bandwidth
.
Band
width
selected is within 10 %
of that
specified .
Switches in an
RC
filter to
reduce
noise on the
display
.
Increases
the
apparent resolution ability of the
analyzer
by
reducing the
modula
tion
between
two
closely
spaced ( in
frequency )
signals on the
display .
Side Panel
BNC
connector
for
applying an
external
trigger
signal
.
Signal
ampli
tude range is +1 V to +10 V , dura
tion
at
least
100
ns
and
frequency
1
MHz or
less . Used
to slave
the
1401
sweep
to an
external device
.
BNC
connector
that
provides a 5
volt
sweep
ramp when
the
SWEEP
MODE selector is in FREE RUN or
TRIG IN
position .
When the
SWEEP
MODE
selector
is
switched
to EXT
IN
position , an
external
sweep signal must be applied to this
connector . A voltage input of V
corresponds to frequency , and +5
V corresponds to 500 MHz , when
the
FREQ
SPAN MHz / DIV
selector
is in the
SEARCH
position
.
Maxi
mum input voltage is +10 V and
maximum
sweep rate is
100
sweeps
/ s .
This
connector
provides the
analyzer
video
output signal
to the
companion
oscilloscope .
Output
level
is
1.2 V
for
full
screen
deflec
tion .
Power Pack Connectors and Switch
AC
POWER
connector
for
applying
AC
power to
charge the
internal
battery
and
operate the
analyzer
.
Line voltage range is either 90 to
136
V
or
180
to
272 V ,
depending
on the
internal connections to the
power
transformer ( see
instructions
for 115 V
/ 230 V
operation
) .
Line
frequency range is 48 Hz to 440
Hz
.
2-7

Operating
Instructions -
1401
EXT DC
POWER
connectors ( red
+
,
and black
- )
for
applying
exter
nal
DC
power
source
to
operate
analyzer
.
Negative
( -
)
connector
is
connected
to
analyzer case
. The
DC
voltage
input
does
not
charge the
internal
battery
.
Reversing
the in
put
voltage
polarity
will
blow
the
power
pack
fuse .
Input
voltage
range
is +6
V to
+16
V.
Initial
surge
current
,
when
the
instrument
is
turned
on
, is
approximately
800
mA .
Power
Pack
Selector
Selects
the
charge rate
for the
power
pack battery
or
switches the
1401 to
an
externally
applied DC
power
source
.
AC
power
source
will
fully
charge
the battery
in
16
hours
with the
selector
at
FULL
CHARGE
position .
TRICKLE
CHG position
will
maintain the
full
charge
state .
Both
positions will
also
supply the
required
power
to
operate
the
1401 ,
as
well as
charge
the
battery
.
EXT
DC
position
disconnects the
battery as the power
source ,
and
connects the
EXT DC
connectors to the
1401 power
supply
so
an
external
DC power
source
( 6
V to
16 V
)
becomes
the
supply
source .
FIRST
TIME
OPERATION
This
procedure
demonstrates
the
functions
of
the
1401
controls
. It
may also be
used as a
general
check
on
the
instrument
operation .
If a
complete
performance
check
is
desired
,
refer to
Section
5
,
Performance
Check
.
WARNING
Unless
a ground
return to
the
signal
source
ground is
provided
,
no
common
ground
exists
between
the
instrument
and
signal
source .
With
no
common
ground
,
the
1401
case may
be
elevated to
a
dangerous
signal
potential .
All
measurements
will
also
be
unreli
able
.
The
ground
return
lead
should
not
be
removed
until all
other
connections
between
the
1401
and
signal
source
have
been
disconnected
and
removed .
The
following
test
equipment
is
required
for
this
procedure
:
A
variable
output
signal
source (
generator
)
with a
frequency
range
within
the 1
MHz to
500
MHz band
,
such
as
Tektronix
Constant
Amplitude
Signal
Generator
067-0532-00 or
Hewlett
- Packard
Model
608D
.
2-8
Pulse
generator
; pulse
repetition
frequency
within 10
Hz
to
1
MHz
,
output
amplitude
+1
V to
+10
V
peak .
Tek
tronix 2101
Pulse
Generator .
1.
Connect
the 1401
to
the
companion
oscilloscope
and
set
the
controls
of
both
instruments as
illustrated
in
Fig .
2-1 .
2.
Check
battery
charge
level
as
follows :
a
.
Switch
POWER
switch
to
ON .
b
.
CHECK -
BATTERY
CHARGE
LEVEL
indicator
.
Charge
level
should
indicate
in
the green
sector
(
see
Operating
Time ,
under
Battery
Care )
. If
battery is
low
,
con
nect
AC
source
to
the
power
pack
and
charge
the
battery
to
full
charge
before
proceeding
with
this
checkout .
NOTE
Refer
to
115 V /
230 V
AC
connector
illustration
and
direction (
Fig .
2-2 ) if
power
source
is
230 V
AC .
3. Check Sweep Mode Operation
a
.
With the
SWEEP
MODE
selector
in
FREE
RUN
posi
tion
,
rotate the RATE
control
through its range
.
b
.
CHECK -
The
sweep
rate
should
vary
from
slow to
fast
(
about 1
sweep /
second to
100
sweeps /
second ) .
c
.
Set
the
RATE
control
midrange
and
switch
the
MODE
selector
to TRIG
IN
position .
d
.
Apply
a
+1 V to
+10 V
trigger
pulse
,
with
a
PRF
between
10
Hz
and 5
MHz ,
from a
pulse
generator to
the
TRIG IN connector .
e
.
CHECK -
Internal sweep
generator
should
trigger
and
generate
a
sweep
voltage
. (
It
will
count
down
from
the
5
MHz
trigger rate . )
f
.
Remove
the
external
trigger
and
switch
the
SWEEP
MODE
selector
back
to
FREE
RUN position .
4.
Check
Freq Span and
Center
Frequency
Range
a
.
Apply a
calibrated
frequency ,
within 1
MHz
to
500
MHz
band
,
below
-30
dBm
, to
the
RF
INPUT
connector .
b
.
CHECK -
With
the
FREQ
SPAN
MHz /
DIV
selector in
SEARCH
position ,
the display
should
contain
the
Hz
frequency
response
at the
left
edge
of
the
display
,
and
the
applied
signal
at
its
relative
frequency
position
on
the 1
MHz to
500 MHz
spectrum
.
(
A )

c .
Adjust the IF GAIN
control
and
the RF
ATTEN
dB
selector for a
signal
amplitude of
approximately 4
divisions .
d .
Rotate
the
RF
CENTER
FREQ
control
towards
000
.
The
frequency
notch
(
see Fig .
2-5 )
should
move
to
the left
and
position
under
the Hz
frequency
response at
a
dial
readout
of
000.
Position the
response under the
division
line .
L
Hz
response
R
Frequency
marker
Fig . 2-5 . Display showing Hz response and frequency marker .
e . Turn the RF CENTER FREQ control towards 500 .
The
frequency notch should
now move to
the right and
position at the display edge when the control reads 500 .
Adjust the
Horiz Gain to
position
the
marker under
the
10 division line .
f . Rotate the
CENTER FREQ
control to
position the
frequency notch under the applied signal . Decrease the
FREQ SPAN
MHz / DIV
setting to .1 ,
keeping
the
signal on
screen with the CENTER FREQ control .
g . CHECK - CENTER FREQ readout dial should indi
cate the frequency of the applied signal , within + ( 5 MHz +
5 % of the indicated readout ) . Fine control must be in the
position .
A
h . Adjust the IF GAIN and / or RF ATTEN dB selector
for a full
screen
signal amplitude .
i . CHECK - Bandwidth of the signal , 6 dB down ( half
amplitude level ) , should equal about 1 division ( 1000 kHz )
± 10 % .
j . Increase the resolution , by switching the RESOLU
TION
selector to 100
kHz
position
.
Decrease
the
frequency
span
to
.01
MHz /
Div .
Operating Instructions - 1401
k .
CHECK -
Resolution
bandwidth
,
at the 6
dB
down
point , should equal about 1 division ( 100 kHz ) ± 10 % .
1.
Switch the
RESOLUTION
selector to 3 kHz
position
and
decrease the FREQ
SPAN
selector to .02
MHz / Div
position . Use the FINE CENTER FREQ control to keep
the signal
centered
on
the screen .
Decrease
the
sweep
RATE
to
maximize the
signal
amplitude and
decrease
the
bandwidth
.
Switch the VIDEO
FILTER on to
reduce noise
on
the
display
.
m
.
CHECK - Resolution bandwidth should equal about
1.5 divisions , ± 10 % .
NOTE
Because incidental FM'ing is more than the resolution
bandwidth at 3 kHz , it may be difficult to accurately
check bandwidth .
n . Return the RESOLUTION selector to 1000 kHz posi
tion and the
FREQ SPAN to
SEARCH
position
.
5.
Check RF
ATTEN dB
Selector
Operation
and
Dynamic
Range of
Vertical Display .
a . Switch the RF ATTEN dB selector to position .
b . Adjust the CENTER FREQ to the applied signal fre
quency and decrease the FREQ SPAN to 1 MHz / DIV pos
ition . ( Keep the signal centered on
screen
with
the
CENTER
FREQ
control . )
c . Push the
LOG
button
for a
logarithmic
display
.
Increase the IF
GAIN control
setting for
optimum gain
without displacing the baseline reference of the display ,
then adjust the signal generator output for a full screen
signal amplitude .
d .
Increase the RF
Atten
dB
selection in 10 dB
steps
.
e . CHECK - Signal amplitude should decrease , in
approximately 1 division steps , as the RF ATTEN dB selec
tor is rotated towards the 60 dB position . In the 60 dB
position , the signal should still be visible above the noise .
( Dynamic range , LOG display , must equal or exceed 60
dB . )
f . Return the RF ATTEN dB selector to and push the
LIN button for linear display . Re - adjust IF GAIN and signal
generator
output for a
full
screen display .
2-9

Operating
Instructions -
1401
g
. Increase
the
signal
generator
output
attenuation
6
dB
and
check vertical
linearity
.
Signal
amplitude
should
decrease
half
screen .
GENERAL
OPERATING
INFORMATION¹
Signal
Application
Connect
the
signal
source
to the
RF
INPUT 50
N con
nector
through
a 50
2
coaxial
cable
with
BNC
connectors
.
Unshielded
leads or connections
, to
the RF
INPUT
connec
tor ,
may
pick
-
up stray
unwanted
signals
which
clutter
the
display
.
The input
impedance
to the
analyzer
is 50
2.
Dis
play
flatness
may be
affected
, if
the signal
source
is
other
than
50 S
, or long
coaxial
cables are
used to
transport
the
signal to
the
RF
INPUT ,
because
of
reflections in the
line
.
Display
flatness
can be
improved
, provided
the
signal
strength
is
adequate , by
increasing
the setting
of
the RF
ATTEN
or by
adding an
external
50
attenuator
( e.g. 20
dB
) at the RF
INPUT connector .
Avoid
applying
high
level (
above
-30
dBm with
the
RF
ATTEN dB
selector at
)
signals
to
the RF
INPUT ,
because
they overload the mixer and IF stages , producing spurious
signals
on
the display
.
Add
attenuation
,
with
the RF
¹Tektronix Measurement Concept booklet ; " Spectrum Analyzer
Measurements
" , Part No.
062-1070-00
, is a
recommended
treatise
on
applications and
measurement evaluation
for
the
1401 .
0.1pW
10μV
2-10
1.0pW
mint
-
100dBm
-90dBm
-80dBm -70dBm
-60dBm
-50dBm
4444
10pW
NOTE
:
Volts RMS --
multiply by
2.8 for
peak to peak
.
dBm 1 milliwatt
=
NORMAL
OPERATING
100μV
RANGE
ImV
100pW
1.OnW 1
On W
ATTEN dB
selector
or if
necessary use
external
attenuators
,
when
signal
compression
is
noticed
( no
increase
in
signal
amplitude
with
an
increase
in
input
power ) . Fig
. 2-6 , a
conversion
chart
, may be
used to
calculate
the
input
signal
level .
100nW
+30
dBm is
the
maximum
power
rating
of the
RF
ATTENuator .
Add external
attenuation if
necessary
to
keep
the
signal
input
level
below
+30
dBm .
Spurious
responses
,
due to
input
signal
overload
, can be
minimized
by
keeping
signal amplitudes
within the
graticule
limits . A
recommended
procedure
is to
adjust the
IF
GAIN
control
for
some
baseline
noise on
the
display ,
then
increase the RF ATTEN dB setting until the strongest
signals are
within the
graticule
limits
.
CAUTION
Resolution and Frequency Span
Resolution is the ability of a spectrum analyzer to
discretely
display
adjacent
signals
within a
frequency span
.
It
is
measured , in
frequency , as
the
separation or
span
between
two discrete
signals
of
equal
amplitude
when
the
notch
or
dip between
them is 3
dB
down . It
is a
function
of
analyzer
bandwidth , sweep
speed ,
frequency
span
,
and
incidental FM .
10mV
romp
-40dBm
-30dBm
-20dBm
-10dBm
1.0μW
10μW
100mV
100μW
Fig
. 2-6 . Volts
- dBm - Watts
conversion
chart for
50 2
impedance .
IV
Auft
4
0dBm
+
10dBm +
20dBm
+ | + |
1.0mW 10mW
100mW
MAXIMUM SIGNAL
WITHOUT
DAMAGE ,
TO THE UNIT IS 30 dBm