Circuit compensating for the attenuation of a notch filter at frequencies less than cut-off frequency thereof

A compensation circuit for the attenuation caused on a line by a series LC type notch filter at frequencies less than the filter cut-off frequency, such filter being connected across the line and a reference voltage node, comprising:

• a first resistor (R) in series in the line and having first and second terminals,
• a series circuit comprising a capacitor (C1) and a second resistor (R1) connected across the line and the reference voltage node, the capacitor being connected on the side of the first terminal of said first resistor, and
• an amplifier (33), the input of which is connected to the connection point of the said capacitor (C1) and of the second resistor (R1) and the output of which is connected to the second terminal of the first resistor (R), such amplifier having a transconductance at said frequencies lower than the filter cut-off frequency of such a value as to feed to the second terminal of said first resistor a current substantially equal to the sum of the currents carried by said series circuit and said notch filter.