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

determining reference response readings obtained on the analyzer or FSVM. When the antenna coupling is measured for radar antennas having waveguide transmission line input, adapters and transition sections should be employed over appropriate portions of the measurement frequency range.

40.5.5  Sample calculations.  The results from the spurious emission measurements will consist of spectrum analyzer photograph or FSVM readings with associated calibration data, measured k factors as necessary plus additional test data such as signal sampler or radar-to-test antenna coupling and insertion losses preceding the point for substituting the calibration signals. Sample spurious emission data forms are shown (see figures 14 through 19).

40.5.5.1  To determine the power spectral level in dBm/kHz from the measured data, use the following sample calculations as a guide:

Measured data at transmitter F o  (5000 MHz):

Frequency separation, first spectrum nulls (from photo): 1.54 MHz

Radar PRF: 650 pps

Spectrum analyzer alpha factor for a 2-microsecond pulsewidth:     20.0 dB Measured signal sampler coupling factor (A  ): 50.0 dB

Attenuation inserted at analyzer input (A  ): 30.0 dB

Signal generator CW calibration level (P     ) at emission spectrum peak:    24.7 dBm

(A1  removed)

Attenuation, signal sampler to radar antenna (A  ): 0 dB

Nominal spectrum analyzer IF bandwidth (B       ): 30 kHz.

First, apply the data analysis procedures given (see 40.4.5) to obtain the maximum spectral level at F

o  which

is 19.3 dBm/kHz. Next consider that the power spectral level at 40 MHz above F  o  is desired but the spectrum envelope is only 4 dB above the noise level, which also increases when the bandwidth is changed. Assume

that the k factor resulting from the change in bandwidth (see 40.5.4.1) is analyzed at 15 MHz above F

o  (where

the power spectral level is 35 dB below the maximum spectral level at F  o). With the following data obtained:

Signal generator (SG) CW level (P CW) at Fo  (frequency of spectrum peak), A 1  removed and 30 kHz BNOM:    24.7 dBm

SG CW level (P       ) at F

+ 15 MHz, A

removed and 30 kHz B

:    59.7 dBm

CW,A               o                                       1                                                                  NOM

SG CW level (PCW,B) at Fo  + 15 MHz, A1  removed and 100 kHz B NOM:    49.2 dBm

SG CW level (PCW,C) at Fo  + 40 MHz, A1  removed and 100 kHz B NOM:    58.5 dBm.

The k factor should be determined as:

k   = PCW,A

PCW,B

=    59.7 dBm     (   49.2 dBm)

=    10.5 dB.

With the analyzer bandwidth of 100 kHz, the CW level at F o  + 40 MHz (PCW,C) is measured    58.5 dBm.

Adding the k factor to compensate for the increase of analyzer bandwidth, the equivalent CW level (P

BNOM  = 30 kHz is:

CW,D) for

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