Impact of Radiated Emission Standards on Digital Radio Receiver Performance

This paper discusses the impact of Radiated Emission Standards on the performance of Digital Radio Receivers. A simple methodology to derive the Bit Error Probability (BEP) for a digital radio receiver with a colocated unintentional interference source is presented, together with a discussion of the difficulties involved in these kinds of estimations. Special attention is made for so called stealth radio applications, where a low signal to noise ratio is required. A comparison is made between the European Community Euronorm EN55022 for commercial equipment and typical military requirements, MIL- STD-461D. This comparison is motivated by the fact that reduced defence budgets in combination with rapid technological advances in civilian information technology , opens the possibility for an increased use of civilian technology in the armed forces. Previous work [1] has showed the impact of emission standards on radio receiver sensitivity and the ambient noise environment. The discussions in [1] are further developed to a methodology to translate emission requirements into consequences for colocated digital radio systems. As a part of this extension, both the interference and receiver sensitivity threshold levels are assumed to be Gaussian distributed, which should be more close to reality than seeing these levels as fixed. The methodology can be used as a rough tool in the design phase of a system to set relevant emission requirements and to evaluate radiated emission test results from colocated equipment. A closing example is presented where BEP versus separation distance, at a fixed value of Signal to Noise Ratio (SNR), is calculated for a Minimum Shift Keying (MSK) radio system, colocated with an undesired source which equals the limits in the standards mentioned above.