A magnetic resonance apparatus with a radio-frequency shield at a reference potential, a detuning circuit and an electrical line which is connected with the detuning circuit. The X and Y values are distances, which when smoothly connected by an appropriate continuing curve, define airfoil profile sections at each distance Z. The OS can also include an assessor to determine whether a user would benefit from the use of an adjusted color space. The counter circuit may be configured to generate the first error signal in response to the output signal and an input signal.