Radar Level Measurement; Overview; Theory Of Operation - Honeywell SmartLine SLN 700 Series User Manual

2.1 Overview

This chapter describes the theory of operation of the transmitter and discusses how
measurements are affected by tank and process conditions.

2.2 Theory of Operation

The fundamental principle of operation is level measurement through the reflection of frequency
modulated radar waves (FMCW technique). The antenna emits a continuous wave of radiation
near 80 GHz whose frequency linearly increases in time in a saw tooth pattern. When the return
pulse is detected by the same antenna, the processing electronics use a Fourier Transform
technique to calculate the difference between the frequency of the generated and reflected signal.
This difference is proportional to the distance of reflection.
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Radar Level Measurement

SLN 700 SmartLine NCR Level Transmitter User's Manual Page 5