外文翻译--频率范围(编辑修改稿)

外文翻译--频率范围(编辑修改稿)内容摘要：

between and MHz is located approximately in the middle of the CB radio range. In addition to inductive radio systems (RFID), ISM applications operating in this frequency range include diathermic apparatus (medical application), high frequency welding equipment (industrial application), remote controlled models and installing 27 MHz RFID systems for industrial applications, particular attention should be given to any high frequency welding equipment that may be located in the vicinity. HF welding equipment generates high field strengths, which may interfere with the operation of RFID systems operating at the same frequency in the planning 27 MHz RFID systems for hospitals (. access systems), consideration should be given to any diathermic apparatus that may be present. 5 Frequency range MHz The range – MHz is located at the lower end of the VHF propagation of waves is limited to the ground wave, so damping due to buildings and other obstacles is less marked. The frequency ranges adjoining this ISM range are occupied by mobile mercial radio systems (forestry, motorway management) and by television broadcasting (VHF range I). The main ISM applications that are operated in this range are telemetry (transmission of measuring data) and remote control applications. The author knows of no RFID systems operating in this range, which can be attributed to the unsuitability of this frequency range for this type of system. The ranges that can be achieved with inductive coupling in this range are significantly lower than those that can be achieved at all the lower frequency ranges that are available, whereas the wavelengths of m in this range are unsuitable for the construction of small and cheap backscatter transponders. 6 Frequency range MHz The frequency range – MHz is allocated to amateur radio services worldwide. Radio amateurs use this range for voice and data transmission and for munication via relay radio stations or homebuilt space satellites. The propagation of waves in this UHF frequency range is approximately strong damping and reflection of ining electromagic waves occurs when buildings and other obstacles are encountered. Depending upon the operating method and transmission power, systems used by radio amateurs achieve distances between30 and 300 km. Worldwide connections are also possible using space satellites. The ISM range – MHz is located approximately in the middle of the amateur radio band and is extremely heavily occupied by a wide range of ISM applications. In addition to backscatter (RFID) systems, baby inters, telemetry ransmitters(including those for domestic applications, . wireless external thermometers), cordless headphones, unregistered LPD walkietalkies for short range radio, keyless entry systems (handheld transmitters for vehicle central locking) and many other applications are crammed into this frequency r。