Radar detector for use in motor car e.g. for acquisition of car environment, has self-test controlling unit and modulator formed, so that test signal is fed into mixer and frequency-shifted opposite to transmitting signal around magnitude

摘要

The detector has a transceiver (12) provided with direct coupling between transmission and receipt paths. A mixer (14) creates an intermediate frequency signal (Z) by mixing a part of a transmitting signal (S) with a signal (E) received in the receipt path. An evaluating unit (16) evaluates the frequency signal, and a self-test controlling unit (22) and a modulator (40) i.e. in-phase/quadrature-modulator, are formed so that a test signal (T) is fed into the mixer, engages part of the transmitting signal and is frequency-shifted opposite to the transmitting signal around a fixed magnitude.