Tektronix 7L5 Manual

*TB 9-6625-2005-35
SUPERSEDED COPY DATED 24 APRIL 1981
DEPARTMENT OF THE ARMY TECHNICAL BULLETIN
CALIBRATION PROCEDURE FOR
SPECTRUM ANALYZER
TEKTRONIX, TYPE 7L5 (PL-1391/U)
W/PLUG-IN L1 AND L3
Headquarters, Department of the Army, Washington, DC
16 June 1988
Approved for public release; distribution is unlimited.
REPORTING OF ERRORS
You can help improve this publication by calling attention to errors and by recommending improvements
and stating your reasons for the recommendations. Your letter or DA Form 2028, Recommended
Changes to Publications, should be mailed directly to Commander, U.S. Army TMDE Support Group,
ATTN: AMXTM-LPP, Redstone Arsenal, AL 35898-5400. A reply will be furnished directly to you.
Paragraph Page
SECTION I. IDENTIFICATION AND DESCRIPTION
Test instrument identification........................................................... 1 2
Forms, records, and reports............................................................. 2 2
Calibration description..................................................................... 3 2
II. EQUIPMENT REQUIREMENTS
Equipment required......................................................................... 4 3
Accessories required....................................................................... 5 3
III. CALIBRATION PROCESS
Preliminary instructions ................................................................... 6 5
Equipment setup............................................................................. 7 6
Readout verification (L3 plug-in only)................................................ 8 7
Calibrator frequency and amplitude.................................................. 9 7
Sweep triggering............................................................................. 10 10
Dot frequency range and accuracy................................................... 11 11
Display dynamic range.................................................................... 12 13
Display flatness .............................................................................. 13 16
Frequency span accuracy and linearity............................................. 14 18
Reference level accuracy (for L3 plug-in only)................................... 15 19
Sweep rate accuracy....................................................................... 16 21
Displayed frequency stability........................................................... 17 22
Final procedure............................................................................... 18 23
*This bulletin supersedes TB 9-6625-2005-35, 24 April 1981, including all changes.
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TB 9-6625-2005-35
SECTION I
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification. This bulletin
provides instructions for the calibration of Spectrum
Analyzer, Tektronix, Type 7L5 (PL-1391/U) w/Plug-in L1
and L3. The manufacturer's manual was used as the
prime data source in compiling these instructions. The
equipment being calibrated will be referred to as the TI
(test instrument) throughout this bulletin.
a. Model Variations. None.
b. Time and Technique. The time required
for this calibration is approximately 6 hours, using the
dc and low frequency technique.
2. Forms, Records, and Reports
a. Forms, records, and reports required for
calibration personnel at all levels are prescribed by TB
750-25.
b. Adjustments to be reported are
designated (R) at the end of the sentence in which they
appear. When adjustments are in tables, the (R) follows
the designated adjustment. Report only those
adjustments made and designated with (R).
3. Calibration Description. TI parameters and
performance specifications which pertain to this
calibration are listed in table 1.
Table 1. Calibration Description
Test instrument
parameters Performance specifications
Calibrator Frequency range: 500 kHz ± 1 Hz
Output voltage: - 40 dBV ±.15 dB
Display Dynamic range: Log 2 dB/DIV = 16 dB (±.15 dB/dB to 1 dB (max)
Accuracy: Log 10 dB/DIV = 80 dB (±.08 dB/dB to 2 dB (max)
Frequency
span/div Range: 50 Hz to 500 kHz Accuracy: ± 5%
Sweep timing Range: 0.01 ms to 10 s
Accuracy: ± ≥5%
Dot frequency 0 Hz to 4999.75 kHz (0° to 50°C ±20 Hz + 10-5 dot readout)
Display flatness Frequency range: 20 Hz to 5 MHz
Accuracy: ±0.7 dB (±0.8 dB for L3 plug-in)
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TB 9-6625-2005-35
Table 1. Calibration Description - Continued
Test instrument
parameters Performance specifications
Frequency
span Range: 50Hz to 500 kHz/DIV Linearity: within 5%
Accuracy: ± 5%
Sweep rate Range: 0.1 ms to 10 s
Accuracy: within 5% of rate selected
Sweep triggering Range: 30Hz to 500 kHz
Level: -1.5 div
Reference level Range L1 L3
-128 dBm to
+21 dBm (50Ω)
-139 dBm to
+10 dBm (600Ω)
Log 2 dB/DIV -128 dBm to
+21 dBm
-141 dBV to
+ 8 dB V (Hi z)
-70 dBm to
+21 dBm (50Ω)
-81 dBm to
+10 dBm (600Ω)
Log 10 dB/DIV -70 dBm to
+21 dBm
-83 dBV to
+8 dBV (Hi Z)
Incremental accuracy When calibrated at -40 dBV in log mode
L1 and L3: Within 0.2 dB/dB with cumulative error of 0.25 dB/10 dB
SECTION II
EQUIPMENT REQUIREMENTS
4. Equipment Required. Table 2 identifies the specific
equipment to be used in this calibration procedure. This
equipment is issued with Secondary Transfer Calibration
Standards Set AN/GSM-287. Alternate items may be
used by the calibrating activity when the equipment
listed in table 2 is not available. The items selected
must be verified to perform satisfactorily prior to use and
must bear evidence of current calibration. The
equipment must meet or exceed the minimum use
specifications listed in table 2.
5. Accessories Required. The accessories listed in
table 3 are issued as indicated in paragraph 4 above and
are used in this calibration procedure. When necessary,
these items may be substituted by equivalent items,
unless specifically prohibited
.
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TB 9-6625-2005-35
Table 2. Minimum Specifications of Equipment Required
Item Common name Minimum use
specifications Manufacturer and model (part number)
A1 AC VOLTMETER Frequency range: 500 kHz
Accuracy: 1% Hewlett-Packard, Model 400EL (7915906)
A2 ATTENUATOR Range: 0 to 90 dB in 10 dB steps
Accuracy: ±0.25% Hewlett-Packard, Model 355D (355D)
A3 ATTENUATOR Range: 0 to 12 dB in 1 dB steps
Accuracy: ±0.25 dB Hewlett-Packard Model 355C (79108075
A4 AUTOTRANSFORMER Range: 105 to 125 V ac
Accuracy: ±1% General Radio, Model W10MT3AS3 or Ridge, Model 9020F (7910809)
A5 DIGITAL
VOLTMETER Voltage range: 0 to 20 V dc Accuracy: ±1% Hewlett-Packard, Model 3490AOPT060
(3490AOPT060)
Dana, Model 5000, or
Dana, Model 5000, w/641
A6 FREQUENCY
COUNTER Range: 499.9995 to 500.005 kHz
Accuracy: 10-6Hewlett-Packard, Model 5345 (MIS-
28754/1 Type 1) w/5355A
A7 OSCILLOSCOPE Must be compatible with TI Tektronix, 7000 series
(to be provided by customer)
A8 OSCILLOSCOPE
CALIBRATOR Markers out: 10 ms to 10 s Ballantine, Model 6126M (MIS-28714 Type 1
A9 TEST OSCILLATOR Frequency: 10 Hz to 5 MHz
Level accuracy: 1% Hewlett-Packard, Model 652A (MIS- 10224)
A10 VERTICAL
AMPLIFIER Must be compatible with 7000 series oscilloscope Tektronix, Types 7A15, 7A16, 7A18, etc.
A11 VARIABLE
ATTENUATOR Range: 0 to 69 dB Accuracy: From test report Weinschel, Model AF117A-69-34 (AF117A-69-34)
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TB 9-6625-2005-35
Table 3. Accessories Required
Item Common name
(official nomenclature) Description (part number)
B1 ADAPTER BNC T-type, 2 jacks, 1 plug (MS35173-274C)
B2 ADAPTER BNC plug terminations (MS35176-491B)
B3 ADAPTER1N plug to BNC jack (10519457) (UG201A/U)
B4 ADAPTER BNC plug to double banana jacks (7909401) (7907592)
B5 ADAPTER1Single banana jack to alligator clip (7907560)
B6 CABLE 30-in., RG-58/U; double banana plug terminations (7907470)
B7 CABLE124-in., RG-58/U; BNC plug terminations (10519141)
B8 EXTENDER1Tektronix, Model 067-0616-00 (067-0616-00)
B9 LEAD 32-in., single banana plug to test hook (red) (7915941-1)
B10 PROBE (TEST LEAD) 36-in., BNC plug to X10 probe, Tektronix, Type P6106 (11513202-
1)
B11 TERMINATION
(DUMMY LOAD) 50-Ωfeed-through; BNC plug to BNC jack (11048B or 11048C)
B12 TEST LEAD Single banana plug to test hook (SKC-4850-14 or 7916122)
1Two required.
SECTION III
CALIBRATION PROCESS
6. Preliminary Instructions
a. The instructions outlined in paragraphs 6 and 7
are preparatory to the calibration process. Personnel
should become familiar with the entire bulletin before
beginning the calibration.
b. Items of equipment used in this procedure are
referenced within the text by common name and item
identification number as listed in tables 2 and 3. For the
identification of equipment referenced by item numbers
prefixed with A, see table 2, and for prefix B, see table 3.
c. Unless otherwise specified, verify the result of
each test and, whenever the test requirement is not met,
take corrective action before continuing with the
calibration. Adjustments required to calibrate the TI are
included in this procedure. Additional maintenance
information is contained in the manufacturer's manual for
this TI.
d. Unless otherwise specified, all controls and
control settings refer to the TI.
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TB 9-6625-2005-35
7. Equipment Setup
WARNING
HIGH VOLTAGE is used or exposed
during the performance of this
calibration. DEATH ON CONTACT
may result if personnel fail to
observe safety precautions.
NOTE
L3 plug-in switch positions are in
parenthesis.
a. Install TI into center compartments of a
4-compartment or right two compartments of a
3-compartment oscilloscope (A7).
b. Select proper oscilloscope controls to
correspond with plug-in compartments occupied by TI.
c. Connect autotransformer (A4) to oscilloscope.
d. Connect autotransformer to a 115-V ac power
source and adjust controls for a 115-V ac output.
e. Set oscilloscope power switch to on and allow
sufficient time for warmup and stabilization.
f. Position controls as listed in (1) through (15)
below: (1) DOT MKR control fully cow (detent
position). (2) FREQUENCY SPAN/DIV switch to MAX.
(3) RESOLUTION (Hz) switch to COUPLED.
(4) REFERENCE LEVEL VAR control fully
cow (detent position).
(5) BASELINE CLIPPER control fully cw.
(6) REFERENCE LEVEL LOG 10 dB/DIV
pushbutton on.
(7) REFERENCE LEVEL switch to -40 dBV.
(8) REFERENCE LEVEL INPUT BUFFER
pushbutton off.
(9) TRIGGERING SOURCE FREE RUN
pushbutton on.
(10) TRIGGERING MODE NORM pushbutton
on.
(11) DIGITAL STORAGE SAVE A pushbutton
to off. (12) DIGITAL STORAGE MAX HOLD
pushbutton off.
(13) dBm/dBV switch to dBV (plugin module
switch). (14) INPUT TERMNZswitch to 50Q (L3 plug-in
only). (15) TIME/DIV switch to AUTO.
g. Connect CALIBRATOR to plug-in INPUT using
cable (B7).
h.Only perform i through I below if L3 plug-in is
being used.
i. Position controls as listed in (1) through (8)
below: (1) LOG 2 dB/DIV pushbutton on.
(2) FREQUENCY SPAN/DIV control to 2
kHz. (3) RESOLUTION (Hz) control to 3 kHz.
(4) TIME/DIV control to 0.2 s.
(5) DIGITAL STORAGE DISPLAY Aand B
pushbuttons on.
(6) VERT POSITION control adjusted to place
display on the bottom horizontal graticule line.
(7) DOT FREQUENCY control to 500.00 kHz.
(8) LOG 10 dB/DIV pushbutton on.
j. Adjust LOG CAL control for a full screen (8
division) display.
k. Push LOG 2 dB/DIV pushbutton to on and
adjust AMPL CAL control (L3) for a full screen display.
I. Repeat i(8) through kabove until displayed
waveform is 8 vertical divisions.
NOTE
Perform m below if L1 plug-in is
being used.
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TB 9-6625-2005-35
m. Position controls as listed in (1) through (10)
below: (1) SWP CAL and HORIZ POSITION controls
adjusted until second and tenth vertical signals are
alined with second and tenth vertical graticule lines
(counted from left edge).
(2) FREQUENCY SPAN/DIV control to 2
kHz.(3) TIME/DIV control to 0.2 s.
(4) DIGITAL STORAGE DISPLAY Aand B
pushbuttons on.
(5) VERT POSITION control adjusted to
place display baseline on bottom horizontal graticule
line. (6) RESOLUTION (Hz) control to 3K.
(7) DOT FREQUENCY CONTROL to 500.00
kHz. (8) LOG CAL control for a fullscreen display.
(9) REFERENCE LEVEL LOG 2dB/DIV
pushbutton on.
(10) AMPL CAL control for a full screen
display.
8. Readout Verification (L3 Plug-in Only)
a. Performance Check
(1) Position controls as listed in (a) through
(c) below: (a)INPUT REF switch to dBm/50ΩΩ .
(b)INPUT TERMNZswitch to 50ΩΩ.
(c)REFERENCE LEVEL control for
+21 dBm.(2) Position INPUT REF switch to dBV and
observe art readout for a +8 dBV indication displayed.
(3) Position INPUT REF switch to dBm/600ΩΩ
and observe crt readout for a +10 dBm indication
displayed.
NOTE
The INPUT connector is a three-
conductor BNC connector with the
outer ring used to detect the
presence of a 10X probe.
(4) Short INPUT outer ring using adapter and
lead (B4 and B12) and observe crt readout for a 20 dB
increase.
b. Adjustments. No adjustments can be made.
9. Calibrator Frequency and Amplitude
a. Performance Check
(1) Connect equipment as shown in figure 1.
(2) Observe frequency counter (A6)
indication. If frequency counter does not indicate
between 499.999 to 500.001 kHz, perform b(1) and (2)
below. (3) Observe digital voltmeter (A5)
indication. If digital voltmeter does not indicate between
.3579 to .3746 V dc, perform b(1) and (3) through (19)
below.
b. Adjustments
(1) Remove TI from oscilloscope and
reconnect to oscilloscope using two extenders (B8).
(2) Adjust Y390 (fig. 2) for a frequency
counter indication of 500.000 kHz.
(3) Remove plug-in module from TI and place
insulating tape (e.g., scotch tape) over pins A13, B13,
A14, B14, A15, and B15 of interface connection (fig. 3).
(4) Reinsert plug-in module in T1.
(5) Connect test oscillator (A9) output (without
the termination) to ac voltmeter (A1), using cable (B7).
(6) Adjust test oscillator controls for an output
frequency of 500 kHz and 10 mV indication on ac
voltmeter.
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TB 9-6625-2005-35
Figure 1. Calibrator accuracy - equipment setup.
(7) Disconnect cable from ac voltmeter input
and reconnect to TI input.
(8) Position controls as listed in (a) through
(d) below: (a)DOT FREQUENCY control for 500
kHz. (b)FREQUENCY SPAN/DIV control for
2 kHz. (c)RESOLUTION (Hz) control to 30 k.
(d)LOG 2 dB/DIV pushbutton on.
(9) Adjust REFERENCE LEVEL control to
display signal at center of crt and note signal position
(reference).
(10) Disconnect cable from input and connect
CALIBRATOR output to input, using cable (B7).
(11) Adjust R892 (fig. 2) for a CALIBRATOR
output amplitude as noted in (9) above.
(12) Connect test oscillator output to ac
voltmeter input, using cable (B7) and termination (B11).
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TB 9-6625-2005-35
(13) Adjust test oscillator controls for an output
frequency of 500 kHz and 10 mV indication on ac
voltmeter.
(14) Disconnect termination from ac voltmeter
and reconnect test oscillator output without termination
to TI plug-in input.
(15) Adjust REFERENCE LEVEL control to
display signal at center of crt and note signal position
(reference).
(16) Remove screws to swing down IF module
assembly so pin 13 is accessible (fig. 4).
(17) Using lead and adapter (B12 and B5)
short pin (B13) (fig. 4) to chassis ground.
Figure 2. Adjustment locations.
Figure 3. Plug-in module rear connector locations.
(18) Adjust R895 (fig. 2) for a CALIBRATOR
output amplitude as noted in (15) above.
(19) Disconnect equipment setup, short, and
tape from pins.
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TB 9-6625-2005-35
Figure 4. IF module swung down to expose internal locations.
10. Sweep Triggering
a. Performance Check
(1) Turn POWER switch of oscilloscope (A7)
to off and install vertical amplifier (A10) in the left
compartment.
(2) Turn POWER switch to on and press
VERT MODE LEFT pushbutton in.
(3) Press TRIG SOURCE LEFT pushbutton in
and connect test oscillator (A9) output to vertical
amplifier CH1 input, using cable and termination (B7 and
B11). (4) Position controls as listed in (a) through
(e) below: (a)DIGITAL STORAGE pushbuttons
off. (b)FREQUENCY SPAN/DIV control for
0.
(c)TRIGGERING SOURCE NORM
pushbutton on. (d)TRIGGERING FREE RUN
pushbutton on. (e)TIME/DIV control to 10 ms.
(5) Adjust test oscillator frequency control for
30 Hz and an amplitude level of 1.5 divisions.
(6) Press TRIGGERING SOURCE INT
pushbutton on and adjust LEVEL/SLOPE control for a
stable triggered display.
(7) Adjust test oscillator frequency control for
500 kHz output and repeat technique of (6) above.
(8) Press TRIGGERING SOURCE FREE
RUN pushbutton on.
(9) Press TRIGGERING MODE SGL SWP
pushbutton and observe that a sweep is initiated on crt.
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TB 9-6625-2005-35
(10) Press TRIGGERING MODE MNL SWP
pushbutton on and adjust MNL SWP control to move
trace over approximately the same range as the normal
sweep.
b. Adjustments. No adjustments can be made.
11. Dot Frequency Range and Accuracy
a. Performance Check
(1) Disconnect test oscillator (A9) output from
vertical amplifier (A10) and connect test oscillator to
INPUT, using cable and adapter (B7 and B1).
(2) Connect INPUT to frequency counter (A6)
input A, using cable (B7).
(3) Position controls as listed in (a) through
(h) below: (a)TRIGGERING SOURCE FREE
RUN pushbutton on.
(b)TRIGGERING MODE NORM
pushbutton on. (c)DOT FREQUENCY control to 500
kHz.
(d)RESOLUTION (Hz) control for
COUPLED. (e)FREQUENCY SPAN/DIV control for
50 (z). (f)TIME/DIV control to AUTO.
(g)LOG 2 dB/DIV pushbutton on.
(h)REFERENCE LEVEL control for -20
dBm.(4) Adjust test oscillator frequency controls for
a 500 kHz signal with 6 divisions of amplitude on the crt.
(5) Adjust test oscillator frequency controls to
place the displayed signal under frequency dot. If
frequency counter does not indicate between 499,994 to
500,006 Hz perform b below.
(6) Repeat technique of (4) above, using
settings listed in table 4. If frequency counter does not
indicate within limits specified, perform b below.
b. Adjustments
(1) Remove TI from mainframe and
reconnect, using two plug-in extenders (B8).
Table 4. Dot Frequency Range and Accuracy
Frequency counter
indications (Hz)
Test
instrument
Crt frequency
indication
(kHz) Min Max
1000.00 999,993 1000,007
1500.00 1499,992 1500,008
2000.00 1999,991 2009,009
2500.00 2499,990 2500,010
3000.00 2999,989 3000,011
3500.00 3499,988 3500,012
4000.00 3999,987 4000,013
4500.00 4499,986 4500,014
4999.75 4999,735 4999,765
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TB 9-6625-2005-35
(2) Remove rf screen cover (on right side of
TI) over honeycomb assembly and turn power on.
(3) Position controls as listed in (a) through
(c) below: (a)FREQUENCY SPMNIDIN control for
0. (b)DOT FREQUENCY control to
2500.00 kHz. (c)DOT MKR control fully ccw (detent
position). (4) Connect digital voltmeter (A5) to base of
Q365 (fig. 5) and chassis ground, using test leads (B9).
Adjust R365 (fig. 5) for digital voltmeter indication of
11.00 V. (5) Disconnect lead from base of Q365 and
connect to pin 7 of U340 (fig. 5). Digital voltmeter will
indicate 4.00 V.
(6) Disconnect lead from pin 7 of U340 and
reconnect to pin 7 of U325 (fig. 5). Digital voltmeter will
indicate 4.00 V.
(7) Disconnect digital voltmeter test leads
from TI. (8) Position FREQUENCY SPAN/DIV control
for 5 kHz and adjust HORIZ POSITION control to center
marker dot on center graticule line.
(9) Position FREQUENCY SPAN/DIV control
to MAX and adjust R655 (fig. 6) to center dot marker on
center graticule line (if necessary).
(10) Adjust DOT FREQUENCY control for
00.00 kHz indication on the crt and connect digital
voltmeter positive lead to pin MH (fig. 5) and negative
lead to chassis ground, using leads (B9). Record digital
voltmeter indication.
(11) Adjust DOT FREQUENCY control for
4999.75 on crt and record new digital voltmeter
indication.
(12) Subtract digital voltmeter value recorded
in (10) above from value recorded in (11) above. If the
difference between the two values is not between 16.60
to 16.70, adjust R345 (fig. 5) for a digital voltmeter
indication of 16.654.
(13) Adjust DOT FREQUENCY control for
99.75 kHz indication on the crt.
(14) Disconnect digital voltmeter positive lead
from pin MH and reconnect to pin ND (fig. 5). Record
digital voltmeter value.
(15) Adjust DOT FREQUENCY control for
100.000 kHz indication on the crt. Record digital
voltmeter new value.
(16) Subtract digital voltmeter value recorded
in (14) above from value recorded in (15) above. If
difference between the two values in not 18.0 V, adjust
R325 (fig. 5) for a digital voltmeter indication of 18.00 V
(difference).
Figure 5. A and B oscillator test point and adjustment location.
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TB 9-6625-2005-35
Figure 6. Sweep timing and dot position adjustment
locations.
(17) Adjust FREQUENCY SPAN/DIV control to
2 kHz and RESOLUTION (kHz) control to 50 (Hz).
(18) Connect TI CALIBRATOR output to TI
INPUT, using cable (B7) and adjust REFERENCE
LEVEL control -30 dBm (approximately).
(19) Observe span accuracy for 100 kHz on
ort. Span accuracy will not exceed ±4 percent.
(20) Adjust DOT FREQUENCY control for
99.75 kHz indication on the crt. Observe span accuracy
for 99.75 kHz on crt. Span accuracy will not exceed ±4
percent.(21) Disconnect CALIBRATOR output from
INPUT.(22) Position FREQUENCY SPAN/DIV control
to any setting other than MAX and adjust HORIZ
POSITION control (front panel) to center marker dot on
crt. (23) Position FREQUENCY SPAN/DIV control
to MAX and adjust DOT FREQUENCY control for
2500.00 kHz display indication.
(24) Connect CALIBRATOR output to INPUT,
using cable (B7) and adjust RESOLUTION (kHz) control
to 30 k.
(25) Adjust HORIZ POSITION control to center
2500.00 kHz marker on center graticule line of crt.
(26) Adjust SWP CAL (front panel) adjustment
for optimum span accuracy from 2500.00 to 500.00 kHz.
(27) Disconnect CALIBRATOR output from TI
plug-in INPUT.
12. Display Dynamic Range
a. Performance Check
(1) Connect equipment as shown in figure 7.
(2) Position controls as listed in (a) through
(g) below: (a)RESOLUTION (Hz) control to
COUPLED.(b)FREQUENCY SPAN/DIV control for
1 kHz.
(c)TIME/DIV switch to AUTO.
(d)LOG 10 dB/DIV pushbutton on.
(e)INPUT REF switch to dBm.
(f)DOT FREQUENCY control for
500.00 kHz.
(g)REFERENCE LEVEL control for -40
dBm. (3) Position attenuators (A2 and A3) to 0 dB
and adjust REFERENCE LEVEL VAR control for full
screen indication.
NOTE
It may be necessary to adjust
reference after every 10 dB step.
(4) Increase attenuator in 10 dB steps to 70
dB, ensuring displayed signal will decrease between 9.5
and 10.5 dB at each 10 dB step.
(5) Increase attenuator to 8 dB (78 dB total),
ensuring displayed signal will be attenuated between 76
to 80 dB.
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TB 9-6625-2005-35
(6) Adjust both attenuator controls to 0 dB.
(7) Position controls as listed in (a) through
(c) below: (a)FREQUENCY SPAN/DIV control for
50 Hz. (b)RESOLUTION (Hz) control for 30 k.
(c)LOG 2dB/DIV pushbutton on.
(8) Repeat technique of (3) above and add 15
dB of attenuation in 2 and 1 dB steps, ensuring
displayed signal will decrease by 1 division for every 2
dB of attenuation.
(9) Total attenuation error of (8) above will not
exceed ±1 dB.
(10) Repeat technique of (3) above with
REFERENCE LEVEL LIN pushbutton on and reference
level adjusted for a 500 pV indication on the crt.
(11) Adjust attenuators for 10 dB and adjust
REFERENCE LEVEL VAR control for an 8 division
amplitude indication on crt.
(12) Increase attenuators 6 dB, ensuring
displayed signal will decrease to 4 ±0.2 divisions.
(13) Increase attenuators 8 dB, ensuring
displayed signal will decrease to 2 ±0.1 divisions.
(14) Adjust attenuators to 10 dB and adjust
REFERENCE LEVEL VAR control fully cw.
(15) Adjust REFERENCE LEVEL control until
displayed signal is at a reference point near full scale
and record signal position on crt.
(16) Adjust REFERENCE LEVEL VAR control
fully ccw (detent position). Displayed signal will
decrease at least 4 divisions.
(17) Adjust attenuators until displayed signal is
at reference point established in (15) above. Change in
attenuation will be 8 dB or more.
(18) Position controls as listed in (a) through
(e) below: (a)dBm/dBV switch to dBm.
Figure 7. Display low accuracy - equipment setup
14

TB 9-6625-2005-35
(b)LOG 2 dB/DIV pushbutton ON.
(c)REFERENCE LEVEL control for -29
dBm.(d)RESOLUTION (Hz) control for 3
kHz. (e) FREQUENCY SPAN/DIV control for
1 kHz.(19) Adjust attenuator for 2 dB attenuation.
(20) Adjust VERT POSITION control as
necessary to establish a graticule reference at signal
peak and record position of signal on crt.
(21) Set REFERENCE LEVEL switch to -30
dbm. (22) Increase attenuator to 3 dB, ensuring
displayed signal will remain within ±0.2 dB of signal level
established in (20) above.
(23) Set REFERENCE LEVEL control to -31
dBm. (24) Increase attenuator to 4 dB, ensuring
displayed signal will remain within ±0.25 dB of signal
level established in (20) above.
(25) Adjust VERT POSITION control as
necessary to establish a new reference point. Record
reference.
(26) Pull REFERENCE LEVEL 10 dB/STEP
control and adjust for a -41 dBm readout.
(27) Increase attenuator to 24 dB, ensuring
displayed signal will remain within ±0.25 dB of signal
level established in (25) above.
(28) Repeat technique of (26) and (27) above,
using settings and indications listed in table 5.
(29) Decrease attenuators to 0 dB.
(30) Press REFERENCE LEVEL LIN
pushbutton on and adjust REFERENCE LEVEL control
to 10 mV. Displayed signal amplitude will be 1 division
±5 percent.
(31) Repeat technique of (29) and (30) above,
using settings and indications listed in table 6. Signal
amplitude will be within limits specified.
b. Adjustments. No adjustments can be made.
Table 5. Attenuation
Test instrument
REFERENCE LEVEL
settings
Attenuator
settings
(dB)
Allowable error
(dB)
-51 34 0.50
-61 44 0.75
-71 54 1.00
-81 64 1.25
-91 74 1.50
-101 84 1.75
-111 94 2.00
-121 104 2.25
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TB 9-6625-2005-35
Table 6. Linearity Accuracy
Test instrument
REFERENCE LEVEL
switch settings
Attenuator
settings
(dB)
Signal amplitude
in divisions
±5 percent
5 mV 0 2
2 mV 0 5
1 mV 6 5
0.5 mV 12 5
0.2 mV 20 5
0.1 mV 26 5
50 µV32 5
20 µV40 5
10 µV46 5
5 µV52 5
2 µV60 5
1 µV66 5
500 nV 72 5
200 nV 80 5
100 nV 86 5
50 nV 92 5
20 nV 100 5
13. Display Flatness
a. Performance Check
(1) Position controls as listed in (a) through
(g) below: (a)DOT FREQUENCY control for
500.000 kHz. (b)RESOLUTION (Hz) control for
COUPLED.(c)FREQUENCY SPAN/DIV control for
100 kHz. (d)TIME/DIV control to AUTO.
(e)LOG 2 dB/DIV pushbutton on.
(f)REFERENCE LEVEL control for -20
dBm indication.
(g)DIGITAL STORAGE pushbuttons
off. (2) Connect test oscillator output to INPUT,
using cable and termination (B7 and B11).
(3) Adjust test oscillator frequency controls for
500 kHz and an output level control of 6 divisions of
amplitude on the crt. Record test oscillator output level
monitor meter indication.
(4) Adjust test oscillator frequency controls to
sweep display on crt while maintaining output level at
level recorded in (3) above to 1 MHz. If display signal
amplitude does not remain within .7 dB (.8 dB for L3
plug-in) from 6 division reference, perform bbelow.
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TB 9-6625-2005-35
(5) Repeat technique of (3) and (4) above
with DOT FREQUENCY control set to 150.000 kHz,
2500.00 kHz, 3500.00 kHz, and 4500.00 kHz.
b. Adjustments
NOTE
No adjustments can be made for
plug-ins L1 through L3, so verify if TI
is out of tolerance or plug-in before
performing adjustments.
(1) Connect CALIBRATOR output to plug-in
INPUT using cable (B7).
(2) Position controls as listed in (a) through (f)
below: (a)DOT FREQUENCY control for 500
kHz.
(b)LOG 2 dB/DIV pushbutton on.
(c)DIGITAL STORAGE pushbuttons
OFF.(d)FREQUENCY SPAN/DIV control for
0.(e)RESOLUTION (Hz) control for 30
kHz. (f)TIME/DIV control to 2 ms.
NOTE
It may be necessary to adjust
REFERENCE LEVEL controls to
position signal on crt.
(3) Observe oscilloscope display for a signal
amplitude of >-30 dBm and adjust L1220 (fig. 8), L1400,
C1604, C1600, and C1042 (fig. 8) for a maximum signal
response (500 kHz) on oscilloscope crt.
Figure 8. 250 kHz IF amplifier, 10.8 MHz input filter and 2d mixer - adjustment and test point locations.
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TB 9-6625-2005-35
14. Frequency Span Accuracy and Linearity
a. Performance Check
(1) Disconnect test oscillator (A9) output from
input and connect CALIBRATOR output to INPUT using
cable (B7).
(2) Position controls as listed in (a) through (f)
below: (a)DOT FREQUENCY control for 0.00
kHz. (b)RESOLUTION (Hz) control for 30
kHz. (c)FREQUENCY SPAN/DIV control for
MAX.(d)TIME/DIV control to AUTO.
(e)REFERENCE LEVEL control for -30
dBm. (f)LOG 10 dB/DIV pushbutton on.
(3) Aline second marker with second graticule
line and verify that each marker right from the second
graticule line is coincident with each graticule line. If 8th
marker is not within 5 percent (±5 division), perform b
below. (4) Disconnect CALIBRATOR output from
INPUT and connect oscilloscope calibrator (A8) marker
output to INPUT, using cable (B7).
(5) Position oscilloscope calibrator controls
for an output of 5 µs.
(6) Position controls as listed in (a) through
(e) below: (a)DOT FREQUENCY control for
4000.00 kHz. (b)FREQUENCY SPAN/DIV control for
200 kHz. (c)RESOLUTION (Hz) control for 10
kHz. (d)REFERENCE LEVEL control for
+10 dBm or as required.
(e)DOT MKR control to MAX CW (dot
to left edge of graticule lines.
(7) Repeat technique of (3) above and verify
8th marker coincident within +.4 division.
(8) Position FREQUENCY SPAN/DIV control
to 100 kHz and position oscilloscope calibrator controls
for an output of 10 ps. Set FREQUENCY SPAN/DIV
control to 100 kHz.
(9) Repeat technique of (3) above and verify
8th marker coincident within ±.5 division.
(10) Repeat technique of (3) above for settings
in table 7.
NOTE
Adjust RESOLUTION (Hz) control as
required to optimize signal
amplitude.
b. Adjustments
(1) Connect oscilloscope calibrator (A8)
marker output to vertical amplifier (A10) input (CH1),
using cable (B7).
(2) Position controls as listed in (a) through
(e) below: (a)TIME DIV control to 10 ms.
(b)FREQUENCY SPAN/DIV control 0.
(c)DIGITAL STORAGE pushbuttons
OFF. (d)TRIGGERING SOURCE INT
pushbutton ON.(e)MODE NORM pushbutton ON.
(3) Adjust oscilloscope calibrator controls for
10 ms markers output.
(4) Adjust triggering LEVEL control for a
triggered display on crt.
(5) Adjust HORIZ POSITION control and
R685 (fig. 6) to position one marker per division.
(6) Repeat technique of (4) and (5) above for
remaining TIME/DIV settings while adjusting
oscilloscope calibrator controls for appropriate time
marker output. Observe crt time markers will be within
±≥5 % of TIME/DIV control setting.
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TB 9-6625-2005-35
Table 7. Frequency Span Accuracy Tolerance within 4%Test instrument
FREQUENCY SPAN/DIV
settings
Oscilloscope
calibrator
control
settings
Displayed
markers/div on the crt
200 kHz 5 µs1 div
100 kHz 10 µs1 div
50 kHz 10 µs2 div
20 kHz 50 µs1 div
10 kHz 1 µs1 div
5 kHz 1 µs2 div
2 kHz 5 µs1 div
1 kHz 1 ms 1 div
.5 kHz 1 ms 2 div
.2 kHz 5 ms 1 div
.1 kHz 10 ms 1 div
50 Hz 10 ms 2 div
(7) Adjust TIME/DIV control to 10 ms.
15. Reference Level Accuracy (for L3 Plug-in only)
a. Performance Check
(1) Position controls as listed in (a) through (j)
below: (a)DOT FREQUENCY control for 1
MHz. (b)RESOLUTION (Hz) control to
COUPLED. (c)FREQUENCY SPAN/DIV control for
10 kHz. (d)INPUT REF switch to dBV.
(e)REFERENCE LEVEL control for -45
dBV. (f)LOG 2 dB/DIV pushbutton on.
(g)TRIGGERING SOURCE FREE
RUN pushbutton on.
(h)TRIGGERING MODE NORM
pushbutton on.
(i)TIME/DIV control to AUTO.
(j)INPUT TERMNZswitch to 50.
(2) Connect test oscillator (A9) output to
variable attenuator (A11), using cable and adapter (B7
and B3). (3) Connect variable attenuator output to
INPUT, using cable and adapter (B7 and B3).
NOTE
Variable attenuator must be used
with test report in the following
steps.
(4) Adjust variable attenuator controls for 48
dB. (5) Adjust test oscillator frequency control to
1 MHz with an output amplitude of 7 vertical divisions on
crt.
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TB 9-6625-2005-35
(6) Adjust REFERENCE LEVEL control for -
37 dBV and variable attenuator controls to 40 dB. If
displayed signal amplitude is not 7 divisions ±0.1 minor
division (0.2 dB), perform b below.
(7) Repeat technique of (4) through (6) above
increasing REFERENCE LEVEL control by 8 dB and
decreasing variable attenuator controls by 8 dB until
reference level is +3 dBV.
b. Adjustments
(1) Position controls as listed in (a) through
(e) below: (a)DOT FREQUENCY control for
1000.00 kHz. (b)INPUT TERMNZswitch to 50ΩΩ.
(c)INPUT REF switch to dBV.
(d)REFERENCE LEVEL control for -21
dBV. (e)LOG 2 dB/DIV pushbutton on.
(2) Set variable attenuator controls for 24 dB
and adjust test oscillator frequency control to 1 MHz with
an output amplitude of 7 divisions on crt.
(3) Adjust REFERENCE LEVEL control for -
13 dBV and variable attenuator controls to 16 dB.
(4) Adjust C126 (fig. 9) for 7 divisions of
amplitude on the crt.
(5) Adjust REFERENCE LEVEL control for
-5 dBV and variable attenuator controls to 8 dB.
(6) Adjust C136 (fig. 9) for 7 divisions of
amplitude on the crt.
(7) Adjust REFERENCE LEVEL control for
+3 dBV and a variable attenuator controls to 0 dB.
(8) Adjust C135 (fig. 9) for 7 divisions of
amplitude on the crt.
(9) Press INPUT BUFFER pushbutton on and
adjust C132 (fig. 9) for 7 divisions amplitude on the crt.
(10) Press INPUT BUFFER pushbutton off and
repeat (3) through (9) above making necessary
adjustments.
(11) Remove cable between variable
attenuator and INPUT.
(12) Connect termination (B11) to variable
attenuator output.
(13) Adjust REFERENCE LEVEL control for
-21 dBV and variable attenuator controls to 8 dB.
(14) Press INPUT TERMNZ switch to 1 M/28
pF and connect probe (B10) to INPUT (check that
readout changed to -1 dBV).
(15) Connect other end of probe to terminator.
Figure 9. L-3 adjustment locations.
20