GB 6113 specifies the radio disturbance and immunity measuring apparatus used for electromagnetic compatibility testing in China. It corresponds in role to the international specification for measuring apparatus and methods, and it exists so that a measurement made with one set of equipment is comparable with a measurement made with another. The document defines the characteristics that the measuring receiver must possess, including the bandwidth of the intermediate frequency stage at each frequency range, the detector types and their time constants, the input impedance and the voltage standing wave ratio, and the behaviour of the receiver at the limits of its dynamic range, and it prescribes the methods by which each characteristic is verified and the tolerances that apply. Requirements are also given for the accessories used with the receiver: the artificial mains network or line impedance stabilisation network, the current probe, the absorbing clamp and the antennas. Calibration intervals and the records that must be kept complete the specification.