A device that determines gradients of a signal compares the change in a signal level between two instants with reference values, and determines a measure for the signal gradient as a function of the comparison. The device functions to effect signal reconstruction, where, for example, the phase of the signal processing clock relative to the gradient measurement clock can be adjusted, or a measure for the signal values between multiple sampling points can be determined. A method for controlling signal curves based on gradient values determines a measure for the gradient curve or the curvature of the signal from the immediate time sequence of multiple gradients. Based on a sequential evaluation of these measures, it is possible to determine the direction of the phase drift of the signal and, for example, to utilize this for synchronization or phase control.