MIL-STD-469 Radar Engineering Interface Requirements, Electromagnetic Compatibility See Notice 1 For Replacement InformationThis standard establishes the engineering interface requirements to control the electromagnetic emission and susceptibility characteristics of all new military radar equipment and systems operating between 100 megahertz MHz, and 100 gigahertz GHz, to ensure EMC in all intended operational environments, and to conserve the frequency spectrum available to military radar systems.

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MIL-STD-469B APPENDIX A

Substituting alpha R and the measured values for the remaining factors in the equation gives:

Pp  =    24.7 + 30.0     0.0 + 50.0 + 23.6

=   78.9 dBm.

40.4.5.6  The last step consists of calculating the maximum power spectral level (P  t), in dBm/kHz as follows:

Pt  = Pp  + 20 log (N x t) + 10 log PRF     PG     90

where: Pt Pp

=   maximum power spectral level, dBm/kHz

=   peak power, dBm

N        =   number of subpulses in the pulse

t          =   emitted pulse duration, microseconds

PRF    =   pulse repetition frequency, Hz

PG      =   processing gain.

The conditions for this example are: (1) no subpulses contained in the pulse (N = 1), and (2) non-FM, non- encoded pulses (PG = 0). Therefore, the calculation of P t  gives:

Pt        = 78.9 + 20 log (1 x 1.3) + 10 log 650     0     90

= 19.3 dBm/kHz.

The value for Pt  is needed for evaluating the end points of the emissions levels in the rolloff region. The criteria for determining the dB below F o  level at the end point of each rolloff region is 60 dB or (P t  + 30) dB, whichever is greater. Evaluating (P t  + 30) dB gives 49.3 dB. Therefore, the 60 dB value applies to the radar in this example since (Pt  + 30) is less than 60 dB.

40.5  Spurious emission.

40.5.1  Objective.  The objective of this test is to measure the power spectral level of all emissions outside the B-40dB  frequency range; these emissions are not determined by the radar emission bandwidth test.

40.5.2  Requirements.  Emissions outside the B -40dB  frequency range should have a power spectral level below the maximum values (see 5.3.2).

40.5.3  Application notes.  For groups B and C radars, this test defines the radar emissions characteristics down to levels 60 dB or (P t  + 30) dB, whichever is greater, below the maximum emission level of the radar fundamental (Fo). For group D radars, the radar emission characteristics are defined down to levels 80 dB below the maximum F o  level. These regions above and below F o  are referenced herein as the rolloff frequency region. The spurious emission tests should extend from the end points of the measured rolloff frequency

regions to the limits of the applicable test frequency range specified (see table VI). The test results should provide the power spectral level, in dBm/kHz, referenced to the terminals of the radar antenna. The spurious emission test procedure should be applied over those portions of the required test frequency range where the radar emission bandwidth test procedure has insufficient sensitivity to verify compliance with the dynamic range, 60 dB or (Pt  + 30) dB below the maximum spectral level of F o  over the specified test frequency range.

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