A method of facilitating an interaction between a user and a product item, the product item having an identity and the method including a number of steps. An amplifier circuit may be coupled between the at least one speaker and the input. The semiconductor device includes the element formation layer provided over a substrate and the antenna provided over the element formation layer. The output circuit includes an output transistor, an output line connected to the output transister, a power supply terminal for the output transistor, and a noise suppression circuit connected between the output line and the power supply terminal a power supply terminal. This complex valued product forms a measure of the current channel estimate to use for updating the stored quantity.