A measurement apparatus (1) for measuring peak pulses of a radio frequency input signal (RF.sub.input) comprises mixing means for mixing the radio frequency input signal (RF.sub.input) with a local oscillator signal (LO) in order to convert the radio frequency input signal (RF.sub.input) directly to zero centre frequency thereby suppressing frequency components in a range close to zero frequency. Control means (20) control the frequency (f.sub.LO) of the local oscillator signal (LO) in a manner that a first measurement is performed in a first frequency range and that a second measurement is performed in a second frequency range shifted from the first frequency range.