Patent ID: 8885840

Claim:
A system for measuring exposure of a user to media, the system comprising: a digital media terminal to present the media, the digital media terminal being equipped with at least an outbound audio facility and an inbound audio facility; an electronic circuit coupled to the outbound audio facility and the inbound audio facility, the electronic circuit comprising: loop-back circuitry to add an inbound signal receivable by the digital media terminal with an outbound signal generated by the outbound audio facility to generate a return signal, and to route the return signal back to the digital media terminal via a signal path connecting to the inbound audio facility; a level detector responsive to a level of the outbound signal; and an attenuator to adjust a level of the inbound signal before the inbound signal is added with the outbound signal to generate the return signal, the attenuator being controllable according to an output of the level detector; and media identification software running in the digital media terminal, the media identification software programmed to process the return signal and to derive media identification information therefrom.