Abstract: A near field RF communicator has an inductive coupler to couple inductively to an H field of an RF signal from another near field RF communicator in near field range to provide a received signal, a demodulator coupled to extract any modulation from a source signal representing a received RF signal to provide an extracted modulation signal; and a controller coupled to receive an extracted modulation signal from the demodulator. The demodulator has a sampler to sample the source signal in sampling periods and to compare signal samples with at least one of other signal samples and a clock or reference signal to remove or reject the carrier of the received RF signal and to extract the modulation.

Abstract: An NFC communicator has an antenna circuit to enable inductive coupling, via an RF H field, of the NFC communicator and another near field RF communicator in near field range. The antenna circuit has an antenna element coupled in parallel with a first capacitor to form a parallel LC circuit. The antenna element has an antenna coil in series with a second capacitor to reduce the voltage to which circuitry of the NFC communicator is subjected by a received RF H field. Alternatively or additionally, receive circuitry of the NFC communicator may be coupled to only a proportion of the antenna coil to reduce the voltage to which circuitry of the NFC, communicator is subjected by a received RF H field.

Abstract: 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.

Abstract: An NFC communicator has an antenna circuit to enable inductive coupling, via an RF H field, of the NFC communicator and another near field RF communicator in near field range. The antenna circuit has an antenna element coupled in parallel with a first capacitor to form a parallel LC circuit. The antenna element has an antenna coil in series with a second capacitor to reduce the voltage to which circuitry of the NFC communicator is subjected by a received RF H field. Alternatively or additionally, receive circuitry of the NFC communicator may be coupled to only a proportion of the antenna coil to reduce the voltage to which circuitry of the NFC, communicator is subjected by a received RF H field.

Abstract: An NFC communicator has an antenna circuit to enable inductive coupling, via an RF H field, of the NFC communicator and another near field RF communicator in near field range. The antenna circuit has an antenna element coupled in parallel with a first capacitor to form a parallel LC circuit. The antenna element has an antenna coil in series with a second capacitor to reduce the voltage to which circuitry of the NFC communicator is subjected by a received RF H field. Alternatively or additionally, receive circuitry of the NFC communicator may be coupled to only a proportion of the antenna coil to reduce the voltage to which circuitry of the NFC communicator is subjected by a received RF H field.

Abstract: A near field RF communicator has an inductive coupler (102) to couple inductively to an H field of an RF signal from another near field RF communicator in near field range to provide a received signal, a demodulator (300) coupled to extract any modulation from a source signal representing a received RF signal to provide an extracted modulation signal; and a controller (107) coupled to receive an extracted modulation signal from the demodulator. The demodulator (300) has a sampler (400) to sample the source signal in sampling periods and to compare signal samples with at least one of other signal samples and a clock or reference signal to remove or reject the carrier of the received RF signal and to extract the modulation.

Abstract: A near field RF communicator has an inductive coupler (102) to couple inductively to an H field of an RF signal from another near field RF communicator in near field range to provide a received signal, a demodulator (300) coupled to extract any modulation from a source signal representing a received RF signal to provide an extracted modulation signal; and a controller (107) coupled to receive an extracted modulation signal from the demodulator. The demodulator (300) has a sampler (400) to sample the source signal in sampling periods and to compare signal samples with at least one of other signal samples and a clock or reference signal to remove or reject the carrier of the received RF signal and to extract the modulation.

Abstract: An NFC communicator has an antenna circuit to enable inductive coupling, via an RF H field, of the NFC communicator and another near field RF communicator in near field range. The antenna circuit has an antenna element coupled in parallel with a first capacitor to form a parallel LC circuit. The antenna element has an antenna coil in series with a second capacitor to reduce the voltage to which circuitry of the NFC communicator is subjected by a received RF H field. Alternatively or additionally, receive circuitry of the NFC communicator may be coupled to only a proportion of the antenna coil to reduce the voltage to which circuitry of the NFC communicator is subjected by a received RF H field.

Abstract: 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.

Abstract: Problems associated with using bipolar differential circuits over a wide common mode voltage range are solved using first and second amplifier circuits 3 and 5, respectively operating over first and second voltage sub-ranges. The low voltage differential signal (LVDS) 1 is applied across a pair of series connected resistors 7 and 9, and to the inputs of the amplifiers 3 and 5. The common mode voltage signal 11 is fed to the inputs of third and fourth amplifiers 15 and 17. The third and fourth amplifiers 15 and 17 ensure that the LVDS receiver has a constant linear transfer characteristic over the differential input signal range and over the full common mode range, especially over the amplifier transition region.