Measuring method for determining attenuation of electromagnetic fields in screening of e.g. housing in range from sixty to hundred and twenty decibels, involves producing electromagnetic field by transmitter with transmitting antenna

摘要

The method involves using a two-stage receiving frequency converter (E) with a modified homodyne principle. A signal coming from a measuring antenna is modulated with a low frequency auxiliary signal in a stage. A reference signal diverted from a transmitter (S) is used as a local oscillator in the receiving frequency converter. The reference signal has a same frequency as a measuring signal of a receiving antenna. An electromagnetic field to be measured is produced by the transmitter with a transmitting antenna such that a common-wave broadcasting characteristic is achieved.