MIL-STD-291C
energy level contained in an 0.5 MHz band centered on the channel frequency. The energy level contained in an 0.5 MHz band centered on a frequency plus or minus 2.0 MHz from the channel frequency shall be at least 38 db below the energy contained in an 0.5 MHz band centered on the channel frequency. Each lobe of the spectrum shall be of less amplitude than the adjacent lobe nearer the multiplied oscillator frequency.
5.13.3 Cw output. Cw output between pulses shall not exceed 0.2 mw.
5.13.4 Pulse shape. The pulse envelope as detected by a linear detector shall fall within the following limits:
5.13.5 Pulse top. The instantaneous amplitude of the pulse shall not, at any instant between the point of leading edge which is 95 percent maximum amplitude and the point of the trailing edge which is 95 percent of the maximum amplitude, fall below a line which is 95 percent of the maximum voltage amplitude of the pulse and is parallel to the base line.
5.13.6 Pulse rise time. The time required for the leading edge of the pulse to rise from 10 to
90 percent shall be 2.0 ± 0.25 µsec.
5.13.7 Pulse fall time. The time required for the trailing edge of the pulse to fall from 90 to
10 percent of its maximum voltage amplitude shall not exceed 3.0 µsec.
5.13.8 Pulse duration. The pulse duration, which is measured between the points on the leading and trailing edges of the pulse which are 50 percent of the maximum voltage amplitude of the pulse, shall be 3.5 ± 0.5 µsec.
5.14 Pulse coding. The pulses shall be coded in pairs, with a spacing which shall be 12 ±
0.5 µsec for X channels, and 36 ± 0.5 µsec for Y channels, as measured at the 50 percent maximum voltage amplitude point from the leading edge of the first pulse to the leading edge of the second pulse.
5.15 Pulse repetition rate. In the air-to-ground mode in the search condition, the interrogating signal from one aircraft shall not exceed 150 pulse pairs per sec; however, an interrogation rate of 135 ± 3 pairs per sec shall be avoided. In the track condition, this number shall not exceed 30 pulse pairs per sec. In the air-to-air mode the interrogations shall not fall below 22 pulses per seconds in both search and track conditions.
5.15.1 Pulse repetition rate variation. The spacing between successive interrogations shall be sufficiently nonuniform to preclude one equipment from locking-on to range replies intended for any other equipment interrogating the same beacon.
5.16 Air-to-Air mode frequency pairing. Sixty-three pairs of Air-to-air (A/A) mode channels in X-mode and 63 pairs in Y-mode shall be available for an A/A link between two airborne interrogator-transponders as shown in table I. Channel 1X or 1Y, transmitting at
6
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business