Transceiver supporting multiple modulation schemes

A transceiver for use in a communications system that uses magnetic field induction to transmit data, the transceiver comprising:

• an antenna;
• a transmit section including:
• an amplifier for driving an antenna;
• a capacitance connected in parallel with the antenna;
• a resistance connected in parallel with the capacitance and the antenna, such that the antenna, capacitance and resistance form a parallel resonant circuit, wherein the value of the resistance is variable to permit adjustment of the loaded quality factor of the resonant circuit;
• and
• a processing unit configured to determine a signal to noise ratio (SNR) of a signal received by the transceiver and to select, based on the determined SNR of the signal received by the transceiver, a modulation scheme for modulating a signal to be transmitted subsequently by the transceiver;
• and
• a receive section, separate from the transmit section, the receive section including:
• a resonant circuit comprising a variable resistance, a capacitance and a self-impedance of the antenna, the variable resistance of the receive section being implemented by inductive or capacitive degeneration.