无绳话机和便携式话机,是一种通过无线电波把接有用户线或中继线的固定话机或基站同用户所持有的无线收发话器、小型话机等移动式话机连接起来的设备。其传输方式的一个显著特点是,使用了一定频率的无线电波在空间传播。如果没有一定的规则来限制空间电波的使用,天空将是一个没有“交通指挥”的、狂乱的电波世界。所以,各国都制定了电波法或无线电法规。其中,严格规定采用无线方式的电话机特性不得对使用频率的其他设备或业务产生干扰。例如,频率范围,输出功率、谐波分量等均不得违反规定。为此,必须对这种无线式话机的特性做必要的测量。 A cordless telephone and a portable telephone are devices that connect a fixed telephone or base station connected with a subscriber line or a trunk via radio waves with a mobile telephone such as a wireless telephone receiver or a small telephone held by the user. A notable feature of its transmission method is the use of a certain frequency of radio waves in space. Without certain rules to limit the use of space waves, the sky will be a frantic world of radio waves without “traffic commanding.” Therefore, all countries have established radio law or radio regulations. Among them, the strict provisions of the wireless telephone features shall not interfere with the use of other devices or services. For example, the frequency range, output power, harmonic components, etc. must not violate the rules. For this reason, the necessary measurements must be made on the characteristics of such wireless handsets.