Separation frequency detection in a radar level gauge

摘要

A separation frequency detector circuit and a method for detection of a separation frequency in a radar level gauge. A first circuit element (1) is arranged to receive a first clock frequency, and a second clock frequency. An instantaneous value of the first clock frequency will be transferred to and held at an output Q of the first circuit element (1) once each period of the second clock frequency. A predetermined value will be transferred to and held at an output Q of a second circuit element (3) triggered by the output Q of the first circuit element (1), and the predetermined value will be cleared from the output Q of the second circuit element (3) a predetermined time period after being triggered. An output is obtainable as a short pulse with a leading edge which will be synchronized with the first change of the leading signal edge of the first circuit element (1).