General Information - Tektronix 191 Instruction Manual

Introduction
The Type 1 91 Constant Ampl itude Signal Generator is
a stable i nstrument which wi l l provide many hours of
trouble-free operation. However, to i nsure measurement
accuracy, it is suggested that you recali brate the instru­
ment after each 500 hours of operation, or every six months
if used intermittently. It wi ll also be necessary to recali­
brate certai n sections of the i nstrument when tubes, tra n­
sistors or other components that affect the cal ibration
accuracy of the i nstrument are replaced.
This cali bration proced ure can be used either for com­
plete calibration of the Type 1 91 to return it to original
performance, or as an operational check of instrument per­
forma nce. Completion of every step in this procedure
returns the Type 1 91 to origi nal factory performance stand­
ards. If it is desired to merely touch up the calibration,
perform only those steps entitled Adjust.
NOTE
The Adjust steps p rovide a check of i nstrume n t
p e rfo rm a n c e before t h e a d justme n t i s m a d e . To
preve n t t h e n e ed for
circuits w h e n p e rformi n g a partial ca l ibration,
readjust only if the l isted tolerance is not met.

General Information

Any needed maintenance should be performed before
proceeding with cali bration. Troubles which become a ppar­
ent during calibration should be corrected using the tech­
niques given in the Maintenance section of the Instruction
Manual.
This procedure is a rranged in a sequence which allows
this i nstrument to be calibrated with the least interaction
of adj ustments and reconnection of equipment.
the steps may be performed out of sequence or a step may
be done i ndividually. However, some adjustments affect
the cali bration of other circuits within the instrument. In
this case, it will be necessary to check the operation of
other parts of the instrument. When a step i nteracts with
others, the steps which need to be checked will be noted.
The location of test points and adj ustments is shown i n
each step. Waveforms which a r e hel pful in determi ning the
correct adj ustment or operation a re also shown.
EQUIPMENT REQUIRED
( se e Figs. 6-1 a n d 6-2 )
General
The following equipment or its equivalent is required
for complete calibration of the Type 1 9 1 . Specifications
given a re the minimum necessary for accurate ca li bration
of this instrument. All test eq ui pment is assumed to be cor­
rectly calibrated and operating withi n the original specifi-
®
SECTION 6
CAI.IBRATION
reca l ibration of other
If desired,
cations. I f equipment is substituted, it m ust meet or exceed
the specifications of the recommended equipment.
Special Test Equipment
For the quickest and most accurate calibration, special
ca l ibration fixtures a re used where necessary. All calibra­
tion fixtures listed under
obtained from Tektronix, I nc. Order by part number through
your local Tektronix Field Office or representative.
1 . DC voltmeter. Mi nimum sensitivity, 20,000 ohms/volt;
accuracy, checked to within 1 "/0 at 6.2 and 1 1 volts, and
checked to within 3 "/0 at 450 volts. For example, Simpson
Model 262.
2. Real-time test osci lloscope. Band pass, DC to 1 0 MHz;
minimum deflection factor, 0.005 volts/division. Tektronix
Type 547 Oscilloscope with Type 1 Al p l ug-in unit or equiv­
alent.
3. Sampling test oscil loscope. Bandwidth, equivalent to
DC to 1 000 MHz; minimum deflection factor, S mil livolts/
division. Tektronix Type 661 Oscilloscope with a Type 4S3
vertical plug-in and a Type 5T3 timing pl ug-in.
4. Standard amplitude calibrator.
within + 0.25 "/0 ; sig nal ampl itude, 0.01 volts to 2 volts;
output frequency, 1 kHz. Tektronix cali bration fixture 067-
0502-00 or equivalent.
5. Time-mark generator. Marker output of 1 j.tS, 5
1 0 j.tS; sine wave outputs of 20 ns a nd 50 ns; accuracy,
0.001 "/0. Tektronix Type 1 84 or equiva lent.
6. Variable autotransformer. Must be capable of sup­
plying at least 25 watts to the Type 1 91 over a voltage
range of 94 to 1 38 volts ( 1 88 to 276 volts for 230-volt nom­
i nal line). If autotransformer does not have an AC volt­
meter to i ndicate output voltage, monitor output with an
AC voltmeter (rms) with range of at least 1 38 (or 276) volts.
For exa m ple, General Radio Wl 0MT3W Metered Variac
Autotransformer.
7. Precision DC voltmeter.
meter resolution, 5 0 j.tV; range, 1 1 volts. For example, Fluke
Model 801 B.
8. 50 ohm voltage pickoff unit. Tektronix VP-2 or equiv­
alent.
9. Termi nation. I m peda nce 50 ohms; accuracy, +1 "/0 ;
connectors, B N C jack t o G R.
0083-00.
1 0. 1 00 X sampling probe. Tektronix P6035 or equiva­
lent.
1 1 . 1 X probe. Tektronix P6028 or eq uiva lent.
1 2. Cable. 5 ns RG-8A / U cable with GR connectors.
Tektronix Part No. 01 7-0502-00.
1 3. Two cables. Impedance 50 ohms; type RG-58A/U:
length, 42 inches, connectors, BNC.
01 2-0057-00.
Eq uipment Required can be
A m plitude accuracy,
j.tS
and
Accuracy, within +0.05"/0 ;
Tektronix Part No. 01 7-
Tektronix Part No.
6-1