| 摘要 |
The motion detector should only respond to objects present within one or more predeterminable distance ranges. In addition to the phase discriminator (32), its receiver circuit contains a down-stream memory (35). The output signal of the phase discriminator, supplied to the memory, is taken from the discriminator by means of clock signals and controlled at times which follow the respective repetitive transmit pulse at a time interval corresponding to the distance of the distance range. An existing comparator circuit (39) has a threshold function (40), in such a manner that an alarm signal is only given when the successive memory values differ from one another by a minimum value with an amplitude corresponding to the threshold. <IMAGE> |
