User's Manual

ROCKWELL COLLINS
COMPONENT MAINTENANCE MANUA L with IPL
TDR-94, PART NO 622-9352
SUBTASK 34-50-96-820-004-A01
D. ATCRBS Reply Pulse Spacing Tolerances
(1) The pulse spacing tolerances for each pulse (including the last framing pulse) with
respect to the first framing pulse of the reply group shall be ±0.05 μs. The pulse spacing
tolerance of the SPI pulse with respect to the last framing pulse of the reply group
shall be ±0.05 μs.
SUBTASK 34-50-96-820-005-A01
E. Mode S Replies
(1) The reply data block is formed by PPM encoding of the reply data. A pulse transmitted
in the first half of the i nterval represents a 1, while a pulse transmitted in the second
half represents a 0.
SUBTASK 34-50-96-820-006-A01
F. Mode S Preamble
(1) The preamble shall consist of four 0.5 ±0.03 μs pulses. The second, third and fourth
pulses shall be spaced 1.0, 3.5, and 4.5 μs respectively from the first transmitted pulse.
The spacing tolerance shall be ±0.30 μs, measured from the first pulse of the reply.
SUBTASK 34-50-96-820-007-A01
G. Mode S Data Pulses
(1) The block of reply data pulses shall begin 8.0 μs after the first transmitted pulse. Either
56 or 112 1-μs intervals shall be assigned to each transmission. A pulse with a width
of 0.5 ±0.03 μs shall be transmitted either in the first or in the second half of each
interval. If a pulse transm itted in the second half of one interval is followed by another
pulse transmitted in the first half of the next interval, the two pulses shall merge and a
1.00 ±0.03 μs pulse shall be transmitted.
SUBTASK 34-50-96-820-008-A01
H. Mode S Reply Pulse S hape
(1) The pulse amplitude variation between one pulse and any other pulse in a reply shall
not exceed 2 dB.
(2) The pulse r i se time shall not exceed 0.1 μs.
(3) The pulse decay time shall not exceed 0.2 μs.
34-50-96
Page 1082
May 18/06