Coil-scanner interface. (a) Interface box incorporating Wilkinson power dividers, T/R-switches, preamplifiers, as well as band-pass and low-pass filters, respectively. The set-up is shown for one 1H and one 13C channel, only; signal paths for the other channels after the power splitters are indicated by dashed lines. For the 13C elements additional low-pass filters are incorporated in the receive path of the MR scanner at the far end of the scanner bore indicated by the blue box right of the system plug. (b) Circuit diagrams of the 1H band-pass (combination of Butterworth 7th order low-pass and 9th order high-pass filters) and 13C low-pass (9th order Butterworth) filter, respectively. (c) Transmission S-parameters S21 for representative band-pass and low-pass filters, indicating high blocking efficiency and low insertion loss at the respective frequencies.