Radio interference classification

Radio interference classification

Radio interference is generally classified into the same frequency interference, adjacent channel interference, out-of-band interference, intermodulation interference, and blocking interference.

Same frequency interference: the frequency of the unwanted signal is the same as the frequency of the wanted signal, and the interference caused by the receiver receiving the same channel useful signal is called co-channel interference;

Adjacent channel interference: interference caused by the interfering channel (station) adjacent channel power falling into the passband of the receiving adjacent channel receiver, called adjacent channel interference;

Out-of-band interference: The interference caused by the harmonics or spurious emissions of the transmitter in the passband that receives the wanted signal, called out-of-band interference;

Intermodulation interference: Intermodulation interference is further divided into transmitter intermodulation interference and receiver intermodulation interference. Transmitter intermodulation interference means that multiple transmitter signals fall into another transmitter and are mutually modulated under the nonlinear action of the final stage amplifier to generate unwanted combined frequencies. The received signal frequency is the same as these combined frequencies. The interference caused by the receiver. Receiver intermodulation interference refers to the interference caused by the nonlinear circuit of the receiver front end when multiple strong signals enter the receiver at the same time, and the intermodulation frequency falls into the receiver's intermediate frequency band;

Blocking interference: When a radio device receives a weak useful signal, it is interfered by a strong interference signal on both sides of the receiving frequency and in the high-frequency loop. This is called blocking interference. Blocking interference reduces the receiving sensitivity, and the communication is interrupted.