VOLTAGE CONTROLLED HARMONIC FILTER
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2002-May-31
Harmonic filters are used in two-way commtmi- cations technology to reject spurious emissions/ harmonics (harmonics are always the multiple of the carrier frequency). The spurious emissions occur with the generation of the transmitter frequency. These filters are built up in-between the transmitter output stage and the antenna or the antenna connection, respectively. In general, many harmonics are generated, which have different amplitudes caused by the various transmitter stages. As the limit regarding the spurious emissions/ harmonics that are allowed to be radiated by the radio is existing (e.g. -1000 MHz < -36 dBm > 1000 MHz > -30 dBm, see ETS 300 086) appropriate measurements have to be taken to assure a sufkient suppression of such unwanted signals. The filter must therefore fulfill a high number of require- ments. It has to be broadbanded, has to have a low insertion loss and should be linear.