An impedance analyzer includes a reference signal, a first converter a first coupler, a second converter, a second coupler, a modification circuit, a reference signal detector, and a reflected signal detector. The first coupler couples the reference signal to the first converter. The first converter produces a reference intermediate frequency signal. The second coupler couples a reflected signal to the second converter. The second converter produces a reflected intermediate frequency signal. A reflection coefficient for a device under test is determined by using a reflected value detected by the reflected signal detector and a reference value detected by the reference signal detector. In a first operating mode of the impedance analyzer, the reflected intermediate frequency signal is forwarded directly to the reflected signal detector. In a second operating mode of the impedance analyzer, the modification circuit operates on the reference intermediate frequency signal to produce an adjustment signal that is combined with the reflected intermediate frequency signal before a resulting signal is forwarded to the reflected signal detector.