Revision A
T-48 90 008 026
2-20
2.12 Pulse
Width,
Spacing,
and Data Pulse Measurements
NOTE
The T-48 Test Set accurately measures each Framing Pulse, Pulse Width, and Pulse Spacing. Each Data
Pulse received will also have the width and spacing measured. Both Mode S and ATCRBS transponders are
tested during the Mode 3A and Mode C portion of the
MANUAL
test sequence only. If no failures are
detected, no display is shown. In the event of a failure, the Test Set will cease testing and display the
failure. The Test Set will display the measured Framing Pulse Width (F1), Spacing between F1 and F2, and
Pulse width of F2.
“
DP
” Signifies a Data Pulse Failure
F1 Pulse Width F1 & F2 Spacing F2 Pulse Width
A “
FAIL”
signifies a F1/F2 Width failure, or a Framing Pulse Spacing Failure.
F1 out of Limits
The operator may also choose to repeatedly measure and test the Pulse Width, Spacing, and Data Pulses by
placing the
STORE/REPEAT
toggle in the “UP” position after completing either the Mode 3A or Mode C
test. The Test Set will then alternately test the appropriate Test (Mode 3A or C) and the Pulse Width
measurements.
MODE 3A FAIL DP
0.45 - 20.35 - 0.45
MODE 3A FAIL
0.55 - 20.35 - 0.45
MODE 3A PASS
0.45 - 20.35 - 0.45
MODE 3A
1234 100% REPLY
Pulse Width, Pulse Spacing, and Data Pulse measurements are not reliable if the T-48
Test Set Receiver efficiency is less than 90%.
