A receiver module of an autonomous implanted capsule receives a human body communication, HBC, signal sensed by an electrode in contact with body tissues or fluids of a patient. The signal is a pulse-modulated, baseband PPM pulse signal. The receiver module comprises a non-linear LNA amplifier stage comprising a pair of complementary transistors arranged as a voltage inverter circuit with an input coupled to the modulated-input-signal collecting electrode. The amplifier stage input is polarized to an intermediate operating point voltage between a supply voltage of the complementary transistor pair and a ground voltage. The amplifier stage has a gain of at least 40 dB, a gain-bandwidth product of at least 20 MHz, and a consumption lower than or equal to 100 nW. It is followed by a downstream demodulator stage made up of a fast comparator circuit of the Threshold Inverter Quantization, TIQ, type, comprising two inverters with cascade-coupled complementary transistors, one of the inverters operating as a voltage reference and the other inverter operating as a gain booster.