A method for modifying an incoming radio frequency (RF) signal at an inductive coupling apparatus comprising: receiving an incoming RF signal; operating a low pass delta sigma modulator circuit or pulse width modulator circuit comprising: receiving an input signal to the delta sigma modulator circuit or pulse width modulator circuit comprising an in-phase - quadrature signal in combination with a frequency of a digital signal source; based on the input signal, providing a frequency offset to a carrier frequency of the incoming RF signal corresponding to a dedicated frequency channel for transmission from the inductive coupling apparatus to a reader apparatus; coupling an output of the delta sigma modulator circuit or pulse width modulator circuit to a control input of a switchable impedance element of a variable impedance circuit; and digitally controlling the output of the variable impedance circuit to generate the frequency offset; switching the switchable impedance element of the variable impedance circuit between at least two states based on the control input, wherein the variable impedance element is in parallel with an inductive element , and wherein the variable impedance circuit has a variable impedance circuit output electrically coupled to the inductive element ; and modifying the incoming RF signal as the coupled impedance (Z) of the inductive element is adjusted in accordance with the output of the variable impedance circuit. receiving an incoming RF signal; operating a low pass delta sigma modulator circuit or pulse width modulator circuit comprising: receiving an input signal to the delta sigma modulator circuit or pulse width modulator circuit comprising an in-phase - quadrature signal in combination with a frequency of a digital signal source; based on the input signal, providing a frequency offset to a carrier frequency of the incoming RF signal corresponding to a dedicated frequency channel for transmission from the inductive coupling apparatus to a reader apparatus; coupling an output of the delta sigma modulator circuit or pulse width modulator circuit to a control input of a switchable impedance element of a variable impedance circuit; and digitally controlling the output of the variable impedance circuit to generate the frequency offset; receiving an input signal to the delta sigma modulator circuit or pulse width modulator circuit comprising an in-phase - quadrature signal in combination with a frequency of a digital signal source; based on the input signal, providing a frequency offset to a carrier frequency of the incoming RF signal corresponding to a dedicated frequency channel for transmission from the inductive coupling apparatus to a reader apparatus; coupling an output of the delta sigma modulator circuit or pulse width modulator circuit to a control input of a switchable impedance element of a variable impedance circuit; and digitally controlling the output of the variable impedance circuit to generate the frequency offset; switching the switchable impedance element of the variable impedance circuit between at least two states based on the control input, wherein the variable impedance element is in parallel with an inductive element , and wherein the variable impedance circuit has a variable impedance circuit output electrically coupled to the inductive element ; and modifying the incoming RF signal as the coupled impedance (Z) of the inductive element is adjusted in accordance with the output of the variable impedance circuit. <EOS>