Performance Check/Calibration - Tektronix 7B70 Time Base Instruction Manual

7B70
(SN B205000 and Up)
SECTION 5
PERFORMANCE CHECK
/
CALIBRA TlON
Change information, if any, affecting this section will be found at the rear of the manual.
Introduction
To assure instrument accuracy, check the calibration of
the 7B70 every 1000 hours or every six months if used
i n f r e q u e n t l y
.
Before calibration, thoroughly clean and
inspect this instrument as outlined in the Maintenance
Section.
The complete Performance Check/Calibration Procedure
can be used to check instrument performance without re-
moving side covers or making internal adjustments by per-
forming all portions except the ADJUST part of the steps.
Screwdriver adjustments which are accessible without re-
moving the covers are adjusted as part of the performance
check procedure. A note titled PERFORMANCE CHECK
ONLY gives instructions which are applicable only t o the
performance check procedure.
Completion of each step in the complete Performance
Check/Calibration Procedure insures that this instrument
meets the electrical specifications given in Section 1. For
best overall instrument performance, when performing a
complete calibration procedure, make each adjustment t o
the exact setting even i f the CHECK i s within the allowable
tolerance.
A Short-Form Procedure is given prior to the complete
procedure. To facilitate instrument calibration, for the
experienced calibrator, the Short-Form Procedure lists the
calibration adjustment necessary for each step and the
applicable tolerances. This procedure also includes the step
number and title as listed in the complete Performance,
Check/Calibration Procedure and the page number on
which each step begins. Therefore, the Short-Form Pro-
cedure can be used as an index to locate a step in the com-
plete procedure. Another feature of the Short-Form Pro-
A partial calibration is often desirable after replacing a
component or to touch up an adjustment of a portion of
the instrument between major recalibrations. For partial
calibration, set the controls as given under Preliminary Con-
trol Settings and start with the desired check or checks. If
any controls need t o be changed from the preliminary
settings for this portion of the calibration procedure, they
are listed under the heading Partial Procedure. To prevent
unnecessary recalibration of other parts of the instrument,
readjust only i f the tolerance given in the CHECK part of
the step is not met. If readjustment is necessary, also check
the calibration of any steps listed in the INTERACTION
part of the step.
TEST EQUIPMENT REQUIRED
General
The following test equipment and accessories, or its
equivalent, are required for complete calibration of the
7B70. Specifications given are the minimum necessary for
accurate calibration. Therefore, some of the recommended
equipment may have specifications which exceed those
given. All test equipment is assumed t o be correctly cali-
brated and operating within the given specifications. If
equipment is substituted, it must meet or exceed the speci-
fications of the recommended equipment.
Special Tektronix calibration fixtures are used in this
procedure only where they facilitate calibration. These
special calibration fixtures are available from Tektronix,
Inc. Order by part number through your local Tektronix
Field Office or representative.
1. Test time-base compatible with the Tektronix
7700-series oscilloscope. 7B71 used in these checks.
cedure is the spaces provided to record performance data or
to check off steps as they are completed. This procedure
2. Vertical amplifier (2 each) for use with Tektronix
may be reproduced and used as a permanent record of
7000-series oscilloscopes. Bandwidth, 200 MHz or greater;
instrument calibration.
deflection factor, 5 volts t o less than 50 millivolts. Tek-
tronix 7A16A used in these checks (a single 7A12 may be
NOTE
used instead of the two 7A16A amplifiers).
AN
waveforms shown in this procedure were taken
3. Oscilloscope. Tektronix 7700 or 7900-series. 7704
w i t h a Tektronix Oscilloscope Camera System.
used in these checks except step 24 (7904).
Limits, tolerances and waveforms in this procedure
are g,'ven as calibration guides and should not be
in terp reted as instrument specifications except as 4. Plug-in extender (Rigid). Tektronix Part Number
stated in Section 1. 067-0589-00.
Scans by ArfekMedia O 2006