TB 9-6625-2211-24
(10) Repeat (6) above with SIF CHAL VID SIF MODE SEL switch set to C.
(11) Repeat (7) above with TRIG SEL DCD MODE SEL switch set to C.
(12) With BIT (MOM) pushbutton pressed, set SIF CHAL VID SIF MODE SEL to
OFF. The reply pulse train will disappear from oscilloscope display and the REPLIES
REPLY INHIB indicator will light.
(13) Set REPLIES MODULATION SEL switch to M4-3P and TRIG SEL DCD
MODE SEL switch to 4.
(14) Press and hold BIT (MOM) pushbutton; 3 pulses will appear on oscilloscope
display and the REPLIES REPLY INHIB indicator will be extinguished.
b. Adjustments. No adjustments can be made.
22. SIF Challenge Video Accuracy
a. Performance Check
NOTE
Ensure oscilloscope CHANNEL 1 input impedance is set to
1MŸ.
(1) Position controls as listed in 7 d above.
(2) Connect equipment as shown in figure 4, connection B.
(3) Set SIF CHAL VID SIF MODE SEL switch to 1.
(4) Adjust oscilloscope controls as necessary to view the pulses on the display.
Measure the spacing between the leading edges of the pulses. The spacing will be 3.0 0.1 Ps.
(5) Measure the pulse amplitude. The pulse amplitude will be 5.0 0.5 V.
(6) Measure the pulse width. The pulse width will be 0.80 0.05 Ps. If not, perform
b below.
(7) Set SIF CHAL VID 5V/20V switch to 20V. Measure the pulse amplitude and
width. The amplitude will be 20.0 4.0 V and the width will be 0.80 0.05 Ps.
(8) Set SIF CHAL VID SIF MODE SEL switch to the settings listed in table 16.
Repeat technique of (4) above. The spacing will be within limits specified.
Table 16. SIF CHAL VID Pulse Spacing
SIF CHAL VID
Oscilloscope
SIF MODE SEL
indications
control settings
(Ps)
2
5.0 0.1
3/A
8.0 0.1
1
C
21.0 0.1
1Set
SIF CHAL VID 5v/20V switch to 5V and repeat this check.
b. Adjustments. Adjust A3R66 (fig. 1) for a pulse width of 0.80 Ps as indicated on
oscilloscope display (R).
34 CHANGE 1