PROPAGATION TIME MEASURING METHOD FOR DETERMINING A DISTANCE

摘要

The invention relates to a device (1) for determining and monitoring a level (e). Said device (1) comprises a transceiver unit (2), a time-delay circuit (21) that is composed at least of a sampling clock oscillator (17) generating a sampling signal (S_sampl) having a certain sampling frequency (f_sampl), a transmission clock oscillator (18) generating a pulse repetition signal (S_PRF) having a certain pulse repetition frequency (f_PRF), and a frequency converter (11) generating a differential signal (S_Diff) by means of sequential sampling, and a control/evaluation unit (7) which determines the level (e) based on the propagation time. An external clock input (25) which is connected to a first clock output (26) of the sampling clock oscillator or a second clock output (27) of the transmission clock oscillator (18) via a timing circuit (24) is provided on the control/evaluation unit (7). The aim of the invention is to create a stabilized and inexpensive control circuit for generating an intermediate frequency signal with a transformation factor that can be determined with great accuracy.