Patent ID: 6836468
Filing Date: 2004-12-28
Classification: G06K,H03L

Abstract:
A radio frequency communications device comprising:an integrated circuit including a transmitter and a receiver, the transmitter selectively transmitting a signal using a modulation scheme to an interrogator in response to receiving an interrogation request from the interrogator, the transmitter being capable of transmitting using Frequency Shift Keying (FSK), Binary Phase Shift Keying (BPSK), On-Off Keying (OOK), and Amplitude Modulation (AM), and being switchable to select between Frequency Shift Keying (FSK), Binary Phase Shift Keying (BPSK), On-Off Keying (OOK), and Amplitude Modulation (AM), wherein, for the selected modulation scheme, a carrier for the transmitter is generated by the integrated circuit itself, instead of by the interrogator to operate the transmitter in an active mode, the integrated circuit further being switchable to transmit in a modulated backscatter mode in which the integrated circuit uses a carrier transmitter by the interrogator, wherein the transmitter is configured to switch between the active mode and the backscatter mode in response to a radio frequency (RF) command from the interrogator.