Before revision: Some texts classify wavemetersas transmission wavemeters, which have an input and an output port and are inserted into the signal path, or absorption wavemeters, which are loosely coupled to the radio frequency source and absorb energy from it.
After revision: There are two categories of wavemeters: transmission wavemeters, which have an input and an output port and are inserted into the signal path, or absorption wavemeters, which are loosely coupled to the radio frequency source and absorb energy from it.