Patent ID: 8224281

Claim:
An apparatus for down-converting an electromagnetic signal, the apparatus comprising: an energy storage module; an energy transfer device configured to receive the electromagnetic signal and a control signal, to down-convert the electromagnetic signal based on the control signal, and to output a down-converted signal that is formed from energy transferred from the electromagnetic signal to the energy storage module at an aliasing rate that is equal to or less than twice the frequency of the electromagnetic signal; an analog-to-digital (A/D) converter configured to receive the down-converted signal from the energy storage module and to generate a down-converted digital signal; and a state machine device configured to receive the down-converted digital signal and to compare the down-converted digital signal to a previous down-converted digital signal, wherein the state machine device uses the down-converted digital signal as feedback to continually modify a frequency and phase relationship between the control signal and the received electromagnetic signal to maintain a specified amplitude for the down-converted digital signal.