An inphase/quadrature (I/Q) mixer in a homodyne radar system , comprising: a radio frequency (RF) input for receiving an RF signal; a local oscillator (LO) input for receiving a LO signal; a first mixer unit receiving the RF signal at a first input of the first mixer unit ; and a second mixer unit receiving the RF signal at a first input of the second mixer unit ; the system being characterised by : a plurality of phase shifters for applying a selectable phase shift to the LO signal to produce a first phase-shifted version of the LO signal and a second phase-shifted version of the LO signal, the first and second phase-shifted versions of the LO signal being in quadrature; a first set of switches being controllable to selectively apply the selectable phase shift to the LO signal; a second set of switches being controllable to apply selectively either one of the first and second phase-shifted versions of the LO signal to one of a second input of the first mixer unit and a second input of the second mixer unit and to apply the other of the first and second phase-shifted versions of the LO signal to the other of the second input of the first mixer unit and the second input of the second mixer unit ; and a counter for generating a count, the count sequencing through states of the first and second sets of switches. a radio frequency (RF) input for receiving an RF signal; a local oscillator (LO) input for receiving a LO signal; a first mixer unit receiving the RF signal at a first input of the first mixer unit ; and a second mixer unit receiving the RF signal at a first input of the second mixer unit ; the system being characterised by : a plurality of phase shifters for applying a selectable phase shift to the LO signal to produce a first phase-shifted version of the LO signal and a second phase-shifted version of the LO signal, the first and second phase-shifted versions of the LO signal being in quadrature; a first set of switches being controllable to selectively apply the selectable phase shift to the LO signal; a second set of switches being controllable to apply selectively either one of the first and second phase-shifted versions of the LO signal to one of a second input of the first mixer unit and a second input of the second mixer unit and to apply the other of the first and second phase-shifted versions of the LO signal to the other of the second input of the first mixer unit and the second input of the second mixer unit ; and a counter for generating a count, the count sequencing through states of the first and second sets of switches. a plurality of phase shifters for applying a selectable phase shift to the LO signal to produce a first phase-shifted version of the LO signal and a second phase-shifted version of the LO signal, the first and second phase-shifted versions of the LO signal being in quadrature; a first set of switches being controllable to selectively apply the selectable phase shift to the LO signal; a second set of switches being controllable to apply selectively either one of the first and second phase-shifted versions of the LO signal to one of a second input of the first mixer unit and a second input of the second mixer unit and to apply the other of the first and second phase-shifted versions of the LO signal to the other of the second input of the first mixer unit and the second input of the second mixer unit ; and a counter for generating a count, the count sequencing through states of the first and second sets of switches. <EOS>