Detecting peaks in a received signal in a near field communications (NFC) device

A near field communications (NFC) device, comprising:

• an antenna configured to receive a radio frequency (RF) signal inductively coupled onto a magnetic field;
• a peak detector configured to determine an envelope of the RF signal;
• and
• a demodulator configured to recover information from the RF signal based upon the envelope of the RF signal.

A peak detector for a near field communications (NFC) device, comprising:

• a clock signal deriver configured to derive a clock signal from a radio frequency (RF) signal;
• a plurality of delay elements configured and arranged to form a delay line to delay the clock signal to provide a delayed clock signal;
• an edge detector configured to detect a rising edge of the clock signal as the clock signal propagates through the delay line;
• and
• a phase comparer configured to receive the clock signal and the delayed clock signal, to provide a first control voltage signal to bias an impedance into a conductive state based on the rising edge for the clock signal and to bias the impedance into a nonconductive state based on the rising edge for the delayed clock signal.

A method for demodulating by a near field communications (NFC) device, comprising:

• (a) receiving, by the NFC device, a radio frequency (RF) signal inductively coupled onto a magnetic field;
• (b) determining, by the NFC device, an envelope of the RF signal;
• and
• (c) recovering, by the NFC device, information from the RF signal based upon a peak detector output.