A near field RF communicator has an antenna circuit (120) to receive a
modulated radio frequency signal by inductive coupling and demodulation
circuitry (130 or 131) to extract the modulation from a received
modulated radio frequency signal inductively coupled to the antenna
circuit. The demodulation circuitry has a virtual earth input comprising
a current mirror. The demodulation circuitry may be formed by an
amplifier (115 or 116) and a demodulator (114) coupled to an output of
the amplifier. The amplifier may be a single input amplifier (116)
coupled to an output of the antenna circuit or may be a differential
amplifier (115) having first and second inputs to receive the modulated
radio frequency signal from first and second outputs of the antenna
circuit, with each amplifier input providing a virtual earth input.