Tektronix 7B80 User manual

Tektronix, lnc.
P.O. Box 500
Beaverton, Oregon 97077
INSTRUCTION MANUAL
Serial Number
Scans by ArtekMedia O 2006
FIRST PRINTING NOV 1975

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7880 Operators
TABLE OF CONTENTS
PAGE PAGE
LIST OF ILLUSTRATIONS .................... ii
LIST OF TABLES ........................... ii
...
SAFETY SUMMARY ........................ 111
SECTION 1 OPERATING INSTRUCTIONS
INSTALLATIOIV ..................... 1-1
CONTROLS. CONNECTORS.
AND INDICATORS
................. '. .. 1-1
FUNCTIONAL CHECK
................. 1-1
Setup Procedure
.................... 1-1
Sweep Functions
.................... 1-4
Triggering Functions
................. 1-4
GENERAL OPERATING INFORMATION
.... 1-5
Triggering Switch Logic
............... 1-5
.................... Triggering Modes 1-5
Trigger Coupling
.................... 1-6
Trigger Source
..................... 1-6
Trigger Slope
...................... 1-7
Trigger Level
...................... 1-7
Horizontal Sweep Rates
............... 1-7
Time Measurement
.................. 1-7
Sweep Magnification
................. 1-7
Variable Hold Off
................... 1-7
Mainframe Operating Modes
............ 1-9
............
REPACKAGING FOR SHIPMENT 1-9
APPLICATIONS
........................ 1.10
TIME-INTERVAL MEASUREMENTS
....... 1.10
....... Period and Frequency Measurements 1.10
..... Rise-Timeand Fall-TimeMeasurements 1.11
............. Pulse Width Measurements 1.12
DELAYED-SWEEPMEASUREMENTS
....... 1.12
X-Y PHASE MEASUREMENTS
............ 1.12
SECTION
2 SPECIFICATION
STANDARD ACCESSOR lES
............. 2-3
SECTION 3 INSTRUMENT OPTIONS
b
REV . A. SEPT . 1977
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7880 Operators
LlST OF ILLUSTRATIONS
FIGURE
NO. PAGE
Frontispiece.
..................... iv
1-1 Location of release latch.
............ 1-1
1-2 Front-panelcontrols, connectors,
and indicators.
................... 1-2
1-3 Effectof LEVELcontroland SLOPE
switch oncrt display
............... 1-8
1-4 Area of graticule used for most accurate
time measurements
................ 1-9
FIGURE
NO. PAGE
1-5 Operation of sweep magnifier
......... 1-9
1-6 Measuringthe periodanddetermining
the frequency of adisplayedwaveform
.. .I-10
1-7 Measuringthe rise time and fall time of
adisplayedwaveform.
............. .l-11
1-8 Measuringthe pulse width of adisplayed
waveform.
..................... .l-12
2-1 7B80dimensional drawing
........... 2-3
LlST OF TABLES
TABLE
NO.
TABLE
PAGE
NO.
PAGE
............. 2-1 Electrical Characteristics. ............ 2-1 2-3 Physical Characteristics. 2-3
2-2 Environmental Characteristics
......... 2-3
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7B80 Operators
This manualcontainssafety information which the user must follow to ensure safe operationof this instrument.WARNING
information
is intendedto protect the operator, CAUTION information is intended to protectthe instrument. The following
are general safety precautions that must be observedduring
all phases of operation.
1 WARNING 1
Ground the Instrument
Toreduce electrical-shockhazard, the mainframe (oscilloscopelchassis must be properly grounded. Refer to the mainframe
manual for grounding information.
Do Not Operate in ExplosiveAtmosphere
Do not operate this instrument in an area where flammablegases or fumes are present. Such operation could cause an
explosion.
Avoid Live Circuits
Electrical-shockhazardsarepresent in thisinstrument. Theprotective instrument coversmust not be removed by operating
personnel. Component replacement and internal adjustmentsmust be referred to qualified servicepersonnel.
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7B80 Operators
7B80 Features
The 7B80 Time-Base unit providescalibrated sweep rates from 5 secondsto 10nanoseconds and triggering to400 megahertz
for 7700-, 7800-, and 7900-seriesoscilloscopes. A XI0Magnifier increases each sweep rate by a factor of 10and a VARI-
ABLE TIMEIDIV control providescontinuously variable sweep rates betweencalibrated steps. Variable holdoff and alpha-
numeric readout are provided. Also, when operating inthe AUTO TRIGGERING MODE, a bright baseline trace
is displayed
inthe absence of atrigger signal. The 7880 can be operated as an independent time base or as a delayed-sweepunitwith acom-
panion delaying time-baseunit.
@
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Section 1-7880
The 7680 Time-Baseunitoperates with a Tektronix 7700-, 7800-,and 7900-seriesoscilloscope mainframes and a 7A-series
amplifier unit toform acompleteoscilloscopesystem. This section describes the operation of the front-panel controls and
connectors, providesgeneral operating information, afunctional check procedure, and basic applications for this instrument.
INSTALLATION
The time-base unit is designed tooperate inthe horizontal
plug-in compartment of the mainframe. This instrument
can also be installedin
a vertical plug-in compartment to
provide
a vertical sweep on the crt. However, when used in
this manner, there are no internal triggering or retrace
blanking provisions, and the unit may not meet the specifi-
cations given inSection 2.
To install the unit in
a plug-incompartment, push it inuntil
it fits firmly intothe compartment. The front panel of the
unitshould be flush with the front panel of the mainframe.
Even though the gain of the mainframe
is standardized,the
sweep calibration of the unitshould be checkedwhen in-
stalled. The procedure for checking the unit is given under
Sweep Functions in the Functional Check procedure inthis
section.
To remove the unit, pull the release latch (see Figure 1-1)
todisengage the unit from the mainframe, and pull
it out of
the plug-in compartment.
CONTROLS, CONNECTORS, AND INDICATORS
All controls, connectors, and indicators required for the
operation of the time-base unit are located on the front
panel. Figure 1-2shows and provides
a brief description of
all front-panel controls, connectors, and indicators. More
detailed information is given in the General Operating
Instructions.
FUNCTIONALCHECK
The following procedures are provided for checkingbasic
instrument functions. Refer tothe description of the con-
trols, connectors, and indicators while performing this pro-
cedure. If performing the functional check procedure
reveals
a malfunction or possible improper adjustment, first
check the operation of the associated plug-in units, then re-
fer tothe instruction manual for maintenanceand adjust-
ment procedures.
Setup Procedure
1. Install the time-base unit being checked inthe A hori-
zontal compartment of the mainframe.
2. Install an amplifier plug-in unit inavertical compart-
ment.
3. Set the time-base unit controls as follows:
SLOPE
MODE
COUPLING
SOURCE
POSITION
TIMEIDIV
VARIABLE
(CAL IN)
HOLDOFF
MAG
(+I
P-PAUTO
AC
INT
Midrange
1ms
Calibrated (Pushed in)
MIN (fullycounter-
clockwise)
XI (pushed in)
4. Turn on the mainframeand allow at least 20 minutes
warmup.
RELEASE
LATCH
1958-3
Fig. 1-1. Location of release latch.
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Operating Instructions-7B80
Fig. 1-2. Front-panel controls, connectors, and indicators.
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OperatingInstructions-7B80
TRIGGERING
@ LEVELControl-Selects a point onthe trigger signal where triggering occurs.
@) SLOPE Switch-Permits sweep tobetriggeredon negativeor positiveqoing portionsof the trigger signal.
@ READY Indicator-Illuminates when sweep circuit is armed (SINGLESWEEP Mode).
@ TRIG'D Indicator-Illuminates when thedisplay istriggered.
@ MODE Pushbunons-Selects the operating mode of thetriggering circuit.
@ COUPLING PushbunonrSelects the method of coupling the trigger signal totriggering circuit.
@ SOURCE Pushbunons-Selects source of the trigger signal.
SWEEP
@ POSITION Control-Provides horizontal positioning.
@ FINEControl-Provides precisehorizontal positioning.
@ MAGPushbunon-Selects magnified XI0or unmagnified sweep.
@ WOLD OFF Control-Permits holdoff periodto be variedtoimprove trigger stability on repetitivecomplex waveforms.
@ TlMElDlV Selector-Selects thesweep rate of the weep generator.
13
VARIABLE Control andCALSwitch--Selectscalibrated or uncalibrated sweep rates. Uncalibrated sweep ratescan
O ba continuously reduced toat least thesweep rateof thenext dower position.
@ SWP CALAdjustment-Compensates for basic timingchanges due tothedifferences insensitivity of mainframes
EXTERNAL TRIGGER INPUT
@ EXTTRlG ATTENUATOR-Selects attenuationfector for external trigger signals.
@ EXTTRlG INConnector-Connector (BNCtype) provides inputfor external trigger signals.
Fig. 1-2. Front-panel controls, connectors, and indicators (cont.).
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