Tektronix L3 User manual

Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-2154-02
I~ktronoo
COMMITTEDTO EXCELLENCE
PLEASE CHECK FOR CHANGE
INFORMATION AT THE REAR
OF THIS MANUAL.
INSTRUCTION MANUAL
First Printing SEP 1976
Serial Number ----- Revised MAY 1981
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Copyright © 1976,1977,1978 Tektronix, Inc. All
rights reserved. Contents of this publication may
not be
reproduced in any form without the written
permission of Tektronix, Inc.
Products of Tektronix, I nco and its subsidiaries
are covered by U.S. and
foreign patents and/or
pending patents.
TEKTRONIX, TEK, SCOPE-MOBILE, and ~
are registered trademarks of Tektronix, Inc.
TELEQUIPMENT is a registered
trademark of
Tektronix U.K. Limited.
Printed in U.S.A.
Specification and price change
privileges are reserved.
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TABLE OF
CONTENTS
P ...
P ...
Section 1 GENERAL INFORMATION Section 3 PERFORMANCE
CHECK
DESCRIPTION 1-1 INTRODUCTION 3-1
ELECTRICAL CHARACTERISTICS 1-1 eQUIPMENT REQUIRED 3-2
ENVIRONMENTAL
PROCEDURE 3-3
CHARACTERISTICS 1-4 Section 4 SERVICE
INFORMATION & DIAGRAM
Section 2 OPERATING INSTRUCTIONS
INTRODUCTION 4-1
INTRODUCTION
2-1 CALIBRATION PROCEDURE 4-2
INST ALLA TION
2-1
CIRCUIT DESCRIPTION 4-6
FRONT PANEL CONTROLS
COMPONENT LOCATIONS 4-9
AND CONNECTOR
2-1
SCHEMATIC DIAGRAM 4-13
INITIAL CALIBRATION
2-2
INPUT IMPEDANCE CHANGE
USING THE ANALYZER 2-3 PROCEDURE 4-18
Impedance
Matching
2-3 Section 5 REPLACEABLE PARTS
LISTS
5-1
Signal Amplitude
2-3 Accessories 5-18
USING THE L3 OPTION 1
WITH BALANCED
Section 6 OPTIONS
CONNECTIONS
2-4 L3
Option 1 6-1
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GENERAL INFORMATION
DESCRIPTION
The L3 Plug-In Moduleis one of aseries of modulesthat
are used with
the Tektronix 7L5 Spectrum Analyzer to
provide
it with various front end capabilities. The L3 has a
switch-selectable input termination: 500,6000, or ahigh
impedance
(1 MO/28 pF) probe compatible input.
Options for the L3 are described in the Optionssection.
ELECTRICAL CHARACTERISTICS
The following electrical characteristics applywhen the
L3 Plug-In Module, in
combination with a 7L5 Spectrum
Analyzer, is installed in a 7000-Series oscilloscope, and
has had a
warm-up period of ten minutes or more.
Intermodulation Distortion
With two on-screen signals within any frequency span
and
of any amplitudes, intermodulation distortion is at
least 75 dB down for third-order products and at least
72 dB down for second-order products.
With two on-screen signals and reference levels
of
-53 dB or less, intermodulation distortion is at least80 dB
down.
With two
out-of-band (>5 MHz) signals equal to or less
than the reference level, second-order intermodulation
products are at least 50 dB down.
With the INPUT BUFFER switch on, second- and
third-
order intermodulation products for any two on-screen
signals within anyfrequency span are at least80 dB down.
Sensitivity
The following tabulation of input noise for each
resolution bandwidth is measured with: 1) an L3 Plug-In
Module installed;
2) the INPUTBUFFER off; 3) theVIDEO
PEAKIVIDEO AVERAGE
control at maximum clockwise
position; 4) the TIME/DIV control set at 10 s; 5) DIGITAL
STORAGE DISPLAY A and Bon; 6) the input impedance
switch
at 50 O.
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Resolution Bandwidth
10 Hz
30 Hz
100 Hz
300 HZ
1 kHz
3 kHz
10 kHz
30 kHz
Equivalent Input Noise
(equal to or less than)
-148 dBV
-146 dBV
-143 dBV
-138 dBV
-133 dBV
-128 dBV
-123 dBV
-118dBV
NOTE
Sensitivity is degraded an additional 8 dB when the
INPUT BUFFER is on (illuminated): e.g., at 3 kHz,
the
equivalent noise would be -120 dBV instead of
-128 dBV. Norse level will increase by approxi-
mately 10 dB when operation is in the Video Peak
mode.
Range
MODE
50n
LOG 2 dB/DIV -128 dBm to +21 dBm
LOG 10 dB/DIV -70 dBm to +21 dBm
Residual Response
Internally generated spurious signals are -143 dBV or
less (referred to the input), or -138 dBV or less for
calibrator harmonics.
Display Flatness
Maximum peak-to-peak amplitude variation is 0.5 dB
from 25 Hz to 5 MHz, or 0.75 dB from 20 Hz to 5 MHz, plus
quantization error if digital storage is used (see 7L5
specifications) .
Reference Level
In the log mode, reference level refers to the top
horizontal graticule line and is calibrated in 1 dB and
10 dB steps.
600n
High Z
-139 dBm to +10 dBm
-141 dBV to +8 dBV
-81 dBm to +10 dBm
-83 dBV to +8 dBV
1-2
General Information-L3
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With operation in LIN mode, reference level calibration
range is from 20 nV/div to 200 mV/div, within 5%, in a 1-2-5
sequence. A variable reference level
control, VAR, can be
used
to increase the display amplitude by ~8 dB.
NOTE
A > sign is displayed adjacent to the reference level
readout when the reference level is not calibrated
due to an incompatible selection of the REFERENCE
LEVEL,
FREQUENCY SPAN/DIV, and TlME/DIV
controls.
Incremental Accuracy
Within 0.2 dB for any 1 dB change of reference level,
with cumulative error of 0.25 dB for any change up to
10 dB.
Within 0.25 dB/10 dBforanychangeof10 dBormore.
Input Connector
The INPUT connector is a three-conductor bnc con-
nector with the outer ring used to detect the presence of a
10X probe so that the reference level readout is changed
by 10X (+20 dB).
NOTE
Readout changes by a factor of only 10X if a 100X
probe is connected.
Input Impedance: Switch selectable; 1 MO in parallel
with 28 pF, 50 0 termination, or 600 0 termination.
Maximum Input Levels
1 MO/28 pF: 15 V pop for ac or pulse signals with
risetimes of 2 V//-ls or faster (pulses or ac beyond this
specification may open an input fuse).
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40 V (dc plus ac) for signals with risetimes slowerthan
2 VI f.1S.
600 n (internally terminated): 12 V dc or rms
(+24 dBm).
50 n (internally terminated):3.5 V dc or rms (+24 dBm).
ENVIRONMENTAL CHARACTERISTICS
The L3 Plug-In Module will meet the foregoing elec-
trical characteristics
when installed in a 7L5 Spectrum
Analyzer within the environmental limits of a 7000-Series
oscilloscope.
Complete details on environmental test
procedures including failure criteria etc., can be obtained
from your local Tektronix Field Office or representative.
1-4 General
Information-L3
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OPERATING INSTRUCTIONS
INTRODUCTION
This section of the manual contains installation instruc-
tions for the L3 plug-in, describes the function of its front
panel controls and connectors, and includes general
operating information suchas initial calibration and signal
application.
INSTALLATION
Visually inspect the 7L5 plug-in cavity to verify the
absence
of any obstruction such as misplaced internal
cables
or packing materials such as cardboard or
styrofoam. Carefully inspect the L3 module to ensure that
the cover plate is properly fastened with no protruding
screw heads.
~
Never install the L3 Plug-In Module without its cover
plate. The metal grounding fingers within the 7L5
cavity will catch and be severely damaged when the
plug-in is removed.
Align the L3 module in front of the 7L5 plug-in
aperature with its edge card connector to the rearand the
dBV/dBm switch tothe right. Carefullyslidethe L3 into the
7L5 plug-in cavity and apply a steady pressure to the L3
front panel until its rear connector is firmly seated and its
front panel is approximately flush with the7L5 front panel.
FRONT PANEL CONTROLS
AND CONNECTOR
AMPL CAL
The AMPL CAL control is a potentiometer that is
adjusted
during theOperational Check tocalibrate the full
screen reference level. This control is used tocompensate
for gain differences in the RF and IF portions of the
instrument. The
AMPL CAL control should be adjusted or
checked for proper setting each time the L3 Plug-In
Module is installed in a 7L5. (Refer to Initial Calibration
Section, which follows.)
INPUT TERMN Z
This three-position switch selects input termination of
50 0, 600 0, or the unterminated input of 1 MO in parallel
with 28 pF.
REV. A APR.1978
Section 2-L3
2-1
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