TB 9-6625-2089-24
(13) Using technique of (2) through (4) above, measure pulse spacing between first
and last pulse. Pulse spacing will be between 70.93 and 71.07 μs.
(14) Set CHAL MODE SELECT switch to 4B. Using technique of (2) through (4)
above, verify that twenty-eight pulses are present in challenge word, at 0, 2, 4, 6, 10, 12, 15,
17, 19, 22, 25, 28, 30, 32, 35, 37, 40, 44, 48, 51, 53, 55, 57, 60, 62, 64, 66, and 70 μs position.
(15) Using technique of (2) through (4) above measure pulse spacing between first
and last pulse. Pulse spacing will be between 69.93 and 70.07 μs.
(16) Position switches as listed in (a) through (c) below:
(a) CHAL MODE SELECT to 1.
(b) CHAL WIDTH SELECT to 0.80.
(c) PRF SELECT to X1.
(17) Adjust oscilloscope controls to position intensified trace over second challenge
pulse, using 0.1 μs markers on CH 2, measure pulse width of 50% amplitude point. Pulse
width will be between 0.75 and 0.85 μs, if not, perform b (1) below.
(18) Measure risetime between 1 and 81 percent amplitude points. Risetime will be
between 0.05 and 0.1 μs.
(19) Measure falltime using technique in (18) above. Falltime will be between 0.05
and 0.2 μs.
(20) Position controls as listed in table 7. Measure pulse width using technique in
(17) above. Pulse width will be as specified, if not, perform appropriate adjustment as
listed in table 7.
Table 7. Challenge Width Accuracy
Test instrument
Oscilloscope
Adjustments (fig. 1) (R)
indications (μS)
CHAL WIDTH
SELECT
Max
Min
Main
Aux
A7R2 for 0.25 μs
0.25
0.20
0.30
A7R13
A7R3 for 0.50 μs
0.50
0.45
0.55
A7R14
A7R5 for 1.70 μs
1.70
1.65
1.75
A7R16
<0.251
>1.72
VARY
---
---
1Adjust
VARY control fully ccw.
2Adjust
VARY control fully cw.
(21) Connect LOW PWR IN to AUX RF IN/OUT and connect CH1 of oscilloscope to
TPB3 (fig. 1) using X10 probe.
(22) Set CHAL WIDTH SELECT switch to 0.80 and repeat (18) through (21) above
for AUX channel. Results will be as specified in (17) through (20) and table 8 for each
measurement. If not, perform appropriate adjustment as indicated for the AUX channel.
(23) Connect oscilloscope CH1 to TPB4 using X1 probe and 75 Ω termination.
Connect oscilloscope CH2 to TPB3 (fig. 1) using X1 probe and 75 Ω termination.
(24) Position CHAL AUX MOD DLY control to 0.2 μs. Measure delay from leading
edge of first CH2 input pulse to leading edge of first CH1 input pulse. Delay will be
between 0.15 and 0.25 μs, if not perform b (2) below.
CHANGE 1 15
