Apparatus for amplifying differential signal

A differential signal amplifying apparatus, comprising:

• a differential amplifier;
• a first impedance component;
• a second impedance component;
• a voltage source;
• and
• a high-pass filter, wherein,
• the differential amplifier receives an input differential signal with a first terminal and a second terminal, the differential amplifier also drains currents from the voltage source into a third terminal and a fourth terminal via the first and the second impedance components respectively, currents drawn by the third and the fourth terminals are GM times as large as voltages received by the first and the second terminals respectively, and GM is a trans-conductance gain of the differential amplifier;
• and
• the high-pass filter receives the input differential signal and outputs a control differential signal to control the first and the second impedance components so that impedances of the first and the second impedance components vary inversely in response to the voltages at the first and second terminals respectively when a state of the input differential signal changes.