Spectrum analyzers and scanning receivers are widely used in EMI laboratories today. Their use for measuring both narrowband and broadband signals requires specific understanding of certain instrument and signal characteristics in order to correctly interpret the displayed results. This article explains methods for the discrimination between narrowband and broadband signals and provides guidance for the proper operation of test instrumentation.
In the rush to complete RF immunity testing on schedule, it is not all that unusual to overlook inherent test equipment limitations. While some test equipment characteristics such as power amplifier harmonics are obviously a limiting factor, the broadband characteristics of antennas, directional couplers, power meters and isotropic field probes can hardly be considered a limitation for most applications. However, when used with power amplifiers exhibiting significant harmonic distortion in Immunity test systems, the broadband characteristics of these devices can result in measurement uncertainty and unacceptable errors.
LATE-BREAKING NEWS UPDATE!
Due to problems in the digital publishing process, MIL-STD-464B 01 October 2010 is scrapped and MIL-STD-464C, release date 01 December 2010 will take its place. There are no technical changes from what are described in this three part article, but the replacement for MIL-STD-464A will be MIL-STD-464C. MIL-STD-464B dated 01 October 2010 will cease to exist.
Standards are increasingly important in our modern global economy – supply chains can be dizzyingly complex, and implementing the economic theory of comparative advantage has been more and more possible as the relative cost of transportation has declined over the years. Since the 1890s, the United States has been the world’s top manufacturing country. The world continues to change. Recently it was reported that China surpassed Japan as the second largest economy, and it is estimated that China will soon surpass the United States.