Spectrum Management – As a general rule, one operator’s radiocommunication is another operator’s RFI (Radio Frequency Interference).
Radio frequencies lie in the broad spectral range of 100 kHz to 100 GHz and employ the principles of radio wave propagation and electrical communications. We concern ourselves here with how the operation of one radio communication system impacts others due to both transmission (what is radiated out of the antenna) and reception (what is received by the antenna). By “what”, we mean the fact that one radio signal can deteriorate proper reception of other radio signals by preventing the associated receiver from properly detecting the information, or data, on that particular signal. By “why”, we mean that the radio frequency spectrum must be shared by many users and many applications in point-to- point communications and broadcasting; as a result, no user can expect to enjoy any particular part of the spectrum on a dedicated basis.
These principles are explored in detail in the book Radio Frequency Interference in Communications, but the idea is relatively simple. RFI is something that occurs by the very nature of this means of communication; as spectrum use increases, so does RFI.
RFI is one category of the much broader field of Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC), defined as follows:
EMI
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. EMI occurs due to physical proximity of components and elements of an electronic device or system, whether through cabinets, cables or antennas.
EMC
Electromagnetic compatibility is the branch of electrical sciences which studies the unintentional generation, propagation and reception of electromagnetic energy with reference to the unwanted effects that such energy may induce. The goal of EMC is the correct operation, in the same electromagnetic environment, of different equipment which use electromagnetic phenomena, and the avoidance of any interference effects. Emission issues are related to the unwanted generation of electromagnetic energy by some source, and to the countermeasures which should be taken in order to reduce such generation and to avoid the escape of any remaining energies into the external environment. Susceptibility or Immunity issues, in contrast, refer to the correct operation of electrical equipment, referred to as the victim, in the presence of unplanned electromagnetic disturbances.
RFI
Radio frequency interference is part of the overall panoply of EMI/EMC; however, as discussed previously, is produced by normal transmission from an antenna and is experienced as that signal enters a receiving antenna of another system not intended to receive it. The investigation of RFI is much like what is involved with normal design of radiocommunication systems used for wireless and satellite applications such that RFI combines with the normal noise sources that impact reception.
Application Technology Strategy has been heavily involved with all aspects of RFI identification and resolution, as applied in wireless systems and satellite communications. We offer our engineering expertise to public and private organizations that demand reliable access to the RF spectrum.