电视发射设备中,除信号主通路(包括从调制到射频功率放大这一主通路)以外,还包括许多附属的电路和同轴元件。这些电路和元件对发射设备的正常工作也非常重要。这些电路和元件的种类很多,例如用于测试的定向耦合器;用于保护的驻波保护电路;同轴开关,假负载及用以滤除带外无用辐射的同轴反射器等 Television transmission equipment, in addition to the main signal path (including the main path from modulation to RF power amplification), also includes a number of subsidiary circuits and coaxial components. These circuits and components are also important for the proper operation of the transmitting equipment. There are many types of these circuits and components, such as directional couplers for testing, standing wave protection circuits for protection, coaxial switches, dummy loads and coaxial reflectors to filter out-of-band unwanted radiation