A demodulator for demodulating a modulated signal has a peak detector (206) with an input (100) coupled to receive the modulated signal and an output (207) to supply a peak detector output signal. The peak detector has a charge storer (314) coupled to the peak detector output so that the peak detector output signal is provided by a voltage across the charge storer (314) and a comparator (313) having a first comparator input coupled to the peak detector input to receive the modulated signal and a second comparator input coupled to the peak detector output to receive the peak detector output signal. The comparator (313) provides a comparison signal representing a comparison between the voltage of the modulated signal and the peak detector output signal. A charging controller (315, 316 and 318) charges the charge storer (314) so as to increase the output voltage when the comparator (313) provides a first signal indicating that the voltage of the modulated signal is higher than the voltage of the peak detector output signal and discharges the charge storer (314) so as to decrease the output voltage when the comparator (313) provides a second signal indicating that the voltage of the modulated signal is lower than the voltage of the peak detector output signal.
