Speed determination appts. using Doppler principle, e.g. for traffic control or door/gate opening

摘要

The equipment includes a Doppler transceiver (10) sending out the pulses and a receiver(s) (D1,D2) receiving the reflected pulses and producing Doppler signals (IF1,IF2) to correspond with the speed of the object. There is at least one pulse shaper (15) for converting the Doppler signals into Doppler pulses (DI1,DI2). The shaper possesses hysteresis characteristics and the hysteresis region lies at least partly below the noise level. A monitoring unit (17) allows evaluation of the Doppler pulses when they have lasted a certain time.