Bandpass filter

A second-order or higher-order filter, comprising at least one bandpass filter configured to receive a temporally modulated periodic input signal Vin(t) and to deliver an output signal Vout(t), the bandpass filter consisting of:

• a phase comparator configured to receive, on a first input, the temporally modulated periodic input signal Vin(t) as first signal, and to generate an output signal with a variable duty cycle;
• and
• an injection-locked oscillator coupled to the phase comparator and configured to directly receive, as input, the output signal from the phase comparator and to generate a signal Vr(t) that is phase-offset with respect to the output signal from the phase comparator;
• said phase-offset signal being applied to a second input of the phase comparator as second input signal;
• and
• said output signal from the phase comparator being the output signal Vout(t) from the bandpass filter and being representative of the phase difference between the two input signals Vin(t) and Vr(t).