A preprocessing circuit for receive signals of a local coil in a magnetic resonance facility (1) includes an arrangement for supplying at least one auxiliary frequency signal of an auxiliary frequency. For at least one or the auxiliary frequency signal, a frequency multiplier generates the auxiliary frequency signal from an intermediate signal transmitted from a receive system of the magnetic resonance facility by way of a transmission link. The multiplier generates the auxiliary frequency signal with a frequency corresponding to a whole-number fraction of the auxiliary frequency.