Electric filter for filtering low frequencies

摘要

The invention relates to an electric filter for filtering low frequencies in order to protect an electronic circuit from ESD. A high-pass filter (1) for filtering low frequencies is used in the signal path between an antenna connector (2) and an electrical circuit (3) in a communication unit. Via the antenna connector different antennas may be connected. The high-pass filter (1) for filtering low frequencies is erected with a capacitance (C1) in the serial path and a inductance (L1) in the parallel path. The high-pass filter (1) allows the protection of the following electrical circuit (3). As an further aspect the high-pass filter has a cutoff frequency lower than the lowest cutoff frequency of a radio frequency separator in the electrical circuit (3).