Abstract: Interrogators, wireless communication systems, methods of operating an interrogator, methods of monitoring movement of a radio frequency identification device, methods of monitoring movement of a remote communication device and movement monitoring methods are provided. According to one aspect, an interrogator includes communication circuitry configured to output a forward wireless signal to a radio frequency identification device and to receive a return wireless signal from the radio frequency identification device; and a processor coupled with the communication circuitry and configured to process the return wireless signal to monitor movement of the radio frequency identification device.

Abstract: A method of communications in a backscatter system, the method comprising transmitting a command at a first power level; and transmitting a continuous wave for a backscatter reply, the continuous wave being transmitted at a second power level different from the first power level. An interrogator for use in a backscatter system, the interrogator comprising a transmitter configured to transmit a command at a first power level and to transmit a continuous wave for a backscatter reply, the transmitter being configured to transmit the continuous wave at a second power level different from the first power level.

Abstract: A pulse position modulation detector divides a timing window into a plurality of pulse position windows, determines the peak magnitude of a signal level received during each pulse position window, compares the peak magnitudes of the signal detected during each pulse position window to determine during which pulse position window the greatest peak magnitude is detected, and generates a bit sequence corresponding to the pulse position window wherein the greatest peak magnitude was detected within the current timing window.