Sensor comprising: • an evaluation unit, • a synchronization unit, and • a two-wire interface, wherein • the two-wire interface is configured ∘ to be connected to a control device in order to receive an electrical supply voltage, provided by the control device, for supplying the sensor with electrical energy, ∘ to receive sync pulses, which are overlaid on the supply voltage, for synchronizing a data transmission from the control device, and ∘ to transmit data to the control device in a predefined time window with respect to a sync time identified by the synchronization unit, whereby data pulses resulting from the data transmission are overlaid on the supply voltage, characterized by • a switchable RC low-pass filter, • wherein the switchable RC low-pass filter is configured ∘ to generate a reference signal (S_REF) by low-pass filtering an input signal (S_IN) of the RC low-pass filter, a characteristic of the input signal (S_IN) corresponding to a characteristic of the overlaid supply voltage, ∘ to exhibit a first time constant in a first mode of the RC low-pass filter, ∘ to exhibit a second time constant in a second mode of the RC low-pass filter, the second time constant being shorter than the first time constant, • the evaluation unit is configured to stabilize the reference signal (S_REF) by o switching the RC low-pass filter to the first mode at least when the supply voltage has an overlaid sync pulse or overlaid data, and o switching the RC low-pass filter to the second mode at least in a period between two sync pulses in which the supply voltage has no overlaid data, and • the synchronization unit is configured o to form a difference signal from the input signal (S_IN) and the reference signal (S_REF), and o to determine a sync time whenever the difference signal exceeds a predefined threshold value. • an evaluation unit, • a synchronization unit, and • a two-wire interface, wherein • the two-wire interface is configured ∘ to be connected to a control device in order to receive an electrical supply voltage, provided by the control device, for supplying the sensor with electrical energy, ∘ to receive sync pulses, which are overlaid on the supply voltage, for synchronizing a data transmission from the control device, and ∘ to transmit data to the control device in a predefined time window with respect to a sync time identified by the synchronization unit, whereby data pulses resulting from the data transmission are overlaid on the supply voltage, ∘ to be connected to a control device in order to receive an electrical supply voltage, provided by the control device, for supplying the sensor with electrical energy, ∘ to receive sync pulses, which are overlaid on the supply voltage, for synchronizing a data transmission from the control device, and ∘ to transmit data to the control device in a predefined time window with respect to a sync time identified by the synchronization unit, whereby data pulses resulting from the data transmission are overlaid on the supply voltage, • a switchable RC low-pass filter, • wherein the switchable RC low-pass filter is configured ∘ to generate a reference signal (S_REF) by low-pass filtering an input signal (S_IN) of the RC low-pass filter, a characteristic of the input signal (S_IN) corresponding to a characteristic of the overlaid supply voltage, ∘ to exhibit a first time constant in a first mode of the RC low-pass filter, ∘ to exhibit a second time constant in a second mode of the RC low-pass filter, the second time constant being shorter than the first time constant, ∘ to generate a reference signal (S_REF) by low-pass filtering an input signal (S_IN) of the RC low-pass filter, a characteristic of the input signal (S_IN) corresponding to a characteristic of the overlaid supply voltage, ∘ to exhibit a first time constant in a first mode of the RC low-pass filter, ∘ to exhibit a second time constant in a second mode of the RC low-pass filter, the second time constant being shorter than the first time constant, • the evaluation unit is configured to stabilize the reference signal (S_REF) by o switching the RC low-pass filter to the first mode at least when the supply voltage has an overlaid sync pulse or overlaid data, and o switching the RC low-pass filter to the second mode at least in a period between two sync pulses in which the supply voltage has no overlaid data, and o switching the RC low-pass filter to the first mode at least when the supply voltage has an overlaid sync pulse or overlaid data, and o switching the RC low-pass filter to the second mode at least in a period between two sync pulses in which the supply voltage has no overlaid data, and • the synchronization unit is configured o to form a difference signal from the input signal (S_IN) and the reference signal (S_REF), and o to determine a sync time whenever the difference signal exceeds a predefined threshold value. o to form a difference signal from the input signal (S_IN) and the reference signal (S_REF), and o to determine a sync time whenever the difference signal exceeds a predefined threshold value.