A measurement system for measuring an input electrical current (Ics) from a current source (CS) and generating a current measurement signal, comprising a current measuring circuit (70) having a first input terminal (72) connected to the current source and an output terminal (74) for providing the current measurement signal. The current measuring circuit further comprises one or more power supply terminals (75, 76) arranged to receive one or more voltages from a power supply (77a, 77b) for powering the current measuring circuit. The current measuring circuit also comprises a first voltage source (VD) coupled to the one or more power supply terminals, the first voltage source providing a disturbance voltage to the one or more power supply terminals, the disturbance voltage representing a voltage at the first input terminal.