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

pCW,D

= pCW,C + k

= 58.5 dBm + ( 10.5 dB)

= 69.0 dBm.

Comparing the resulting level to the CW level at the spectrum maximum obtains 24.7 dBm ( 69.0 dBm) =

44.3 dB below maximum power spectral level. The power spectral level at F o was 19.3 dBm/kHz. Therefore, the power spectral level at F o + 40 MHz is 19.3 dBm/kHz 44.3 dB = 25.0 dBm/kHz.

40.6 Frequency stability.

40.6.1 Objective. The objective of this test should be to determine the frequency stability of the radar transmitter.

40.6.2 Requirements. Radar transmitters should achieve a frequency tolerance no larger than that given

(see 5.3.3) for the appropriate radar category.

40.6.3 Application notes. This test should be performed in-line using the system directional coupler or other suitable coupling devices. The radar transmitter should be tuned to an operating frequency near the midpoint of the tuning band. If the radar system operates on more than one band, the tests should be performed for each band. The preferred test technique should be to automatically measure and record the frequency.

40.6.3.1 The transmitter output signal should be obtained from the transmitter signal sampler or a test signal sampler inserted between the transmitter output and antenna input. Alternative test points between the transmitter frequency determining circuits and the final output should be used providing that (1) the frequency at the point of measurement equals the final output frequency and (2) connection of the test instrumentation should not alter the transmitter operation. The attenuators in the diagram should be needed to reduce the

signal levels to within the input level capabilities of the test instrumentation.

40.6.3.2 The test instrumentation should provide a measurement accuracy which is equal to or better than

5 percent of the specified maximum frequency tolerance. For example, a group C, category 1, radar operating at 100 MHz would have a maximum tolerance of: (400/10 6) (100 x 106 Hz) = 0.04 MHz. For a measurement accuracy of 5 percent, the frequency should be determined within 5 percent of 0.04 MHz = 2000 Hz or 20 parts per 106 at the operating frequency of 100 MHz.

40.6.3.3 The transmitter frequency stability should be measured at the highest and lowest temperature for which the equipment is designed to operate. Temperatures should be established and maintained in

accordance with procedures specified in MIL-STD-810, methods 501.1 and 502.1.

40.6.4 Procedure. The frequency stability measurement block diagram should be as shown on figure 20. The test duration should be a minimum of 4 hours with the following measurement intervals:

a. Within first hour: After transmitter turn-on, at time T o, measure frequency at 10-second intervals during first 2 minutes of operation. Beginning at times of T o + n minutes, where n = 5, 10, 15... up to 60, measure frequency at 10-second intervals for a period of 1 minute.

b. Over next 3 hours: Measure frequency at times of T o + 60 + n minutes where n = 0, 10, 20, 30... up to and including n = 180.