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众所周知,在许多频分系统中,诸如选呼电话、遥控遥测装置、工业控制设备、巡回检测装置、无线电通讯等等,都常常利用频率区分控制对象并传送不同的信息。欲使各控制对象和传送的信息之间互不串扰,就要合理地选择频率。一般说来,频率的选择应根据下面几点综合考虑:1.频率应在一定的频带内选取。系统不同,相应的工作频带也各异。例如,选呼电话宜在音频范围内选取;遥控、遥测装置宜在话音频率和超音频范围
It is well-known that in many frequency division systems, such as selective call telephones, telemetry devices, industrial control devices, tour detection devices, radio communications, etc., often make use of frequency to distinguish between control objects and to convey different information. For each control object and the transmission of information without cross-talk, it is necessary to choose a reasonable frequency. In general, the frequency of selection should be based on the following considerations: 1. Frequency should be selected within a certain band. Different systems, the corresponding working frequency is also different. For example, selective call should be selected in the audio range; remote control, telemetry devices should be in the voice frequency and super audio range