Detection of amplitude, regulation of amplitude and detection of direction of an oscillation of an oscillatory body

A device for detecting a direction in which an oscillatory body moves during an oscillation about an oscillation axis, the device comprising:

• the oscillatory body comprising at least one movable electrode;
• a first stationary electrode on a first side of the oscillation axis and a second stationary electrode on a second side of the oscillation axis,
• wherein a first change in a first capacitance between the at least one movable electrode and the first stationary electrode and a second change in a second capacitance between the at least one movable electrode and the second stationary electrode take place during the oscillation,
• a detection circuit to:
• detect a first signal representing a measure of the first change in the first capacitance over time before a crossing through a reference position of the oscillation, and
• detect a second signal representing a measure of the second change in the second capacitance over time before the crossing through the reference position of the oscillation;
• and
• an evaluation circuit to:
• determine an asymmetry of a difference of the first signal and the second signal with respect to an oscillation angle, and
• determine, using the asymmetry, the direction in which the oscillatory body moves during the oscillation before the crossing through the reference position of the oscillation.

A method for detecting and/or regulating an amplitude of an oscillation of an oscillatory body about an oscillation axis, wherein a change in a capacitance between at least one electrode of the oscillatory body and a stationary electrode takes place during the oscillation of the oscillatory body, wherein the method comprises:

• detecting a signal, representing a measure of the change in capacitance, over time;
• ascertaining a pulse width of a pulse in the signal before a crossing through a reference position of the oscillation;
• determining information from the pulse width,
• the information being a measure of a time interval between a point in time of a predetermined event in the signal, corresponding to an angular position of the oscillatory body, and a point in time of the crossing;
• determining a period of the oscillation;
• and
• at least one of:
• calculating the amplitude based on the information and the period of the oscillation, or
• regulating the amplitude using the information and the period of the oscillation.

A method for detecting a direction in which an oscillatory body moves during an oscillation about an oscillation axis, wherein the oscillatory body comprises at least one movable electrode, wherein a first stationary electrode is arranged on a first side of the oscillation axis and a second stationary electrode is arranged on a second side of the oscillation axis, wherein a first change in a first capacitance between the at least one movable electrode and the first stationary electrode and a second change in a second capacitance between the at least one movable electrode and the second stationary electrode take place during the oscillation of the oscillatory body, wherein the method comprises:

• detecting a first signal representing a measure of the first change in the first capacitance over time before a crossing through a reference position of the oscillation;
• detecting a second signal representing a measure of the second change in the second capacitance over time before the crossing through the reference position of the oscillation;
• determining an asymmetry of a difference of the first signal and the second signal with respect to an oscillation angle;
• and
• determining, using the asymmetry, the direction in which the oscillatory body moves during the oscillation before the crossing through the reference position of the oscillation.