The invention discloses a differential LC high-pass filter device with a programmable
cut-off frequency, relates to the technical field of power line carrier communication
interference resistance, and solves the technical problems that the
signal-to-
noise ratio of a
signal is seriously compressed due to pulse
ringing of an existing fixed HPF high-pass filter, an analog front-end low-
noise amplifier is saturated, and a
receiver is blocked. According to the technical scheme, a bipolar
triode is adopted as an
electronic switch, a fixed L / C high-pass filter is configured to be a programmable filter, the
cut-off frequency of the filter is adjusted as required, and the anti-interference performance of the high-frequency carrier
receiver is improved; a bypass
capacitor is connected in parallel to a base
electrode and an emitting
electrode, high-frequency feedback current leaked from a Miller
capacitor of a
triode to the base
electrode is shunted, the influence on
output impedance is reduced, and impedance balance at the two differential ends is kept; and meanwhile, the
ringing duration of the L / C high-pass filter is reduced, and the blocking
recovery time of the
receiver is shortened under
strong pulse interference.