A continuous-time filter system comprises a master control unit and a slave unit with one or more slave filters. The master control unit includes an integrator having circuit elements which match those elements of the slave filter that define the slave filter's time constant. The master control unit further includes a voltage comparator connected to an output of the integrator, the voltage comparator providing an output frequency signal, and a phase frequency comparator providing a control signal as an output signal, the phase frequency comparator receiving said output frequency signal and a reference frequency signal as input signals. The slave unit includes said at least one slave filter, the slave filter having a control signal input for receiving said control signal thus allowing to calibrate the slave filter's transfer function by influencing the slave filter's time constant.