Frequency-Modulated Continuous-Wave (FMCW)

摘要

A frequency-modulated continuous-wave (FMCW) radar system for level or distance measurement in which a frequency modulated signal to be transmitted to a target is mixed with an echo signal from the target to produce a beat signal that passes through an analog filter before being digitized and processed in a digital processor to determine the level or distance to be measured, where a test signal is generated by a signal generator, and a switch is controlled to connect the beat signal or the test signal to the analog filter, the signal generator generates the test signal as a broadband signal having a periodic waveform, e.g., a square wave, and the digital processor calculates a spectrum of the digitized filtered test signal by Fast Fourier Transform and generates a fault signal if the spectrum differs from a reference spectrum by a predetermined amount to allow for failure detection.

主权项

1. A frequency-modulated continuous wave (FMCW) radar system for level or distance measurement, comprising:
a transmitter/receiver for generating a frequency modulated signal to be transmitted to a target and for mixing an echo signal received from the target with the generated frequency modulated signal to produce a beat signal; an analog filter for filtering the produced beat signal; a digital processor for digitizing the filtered beat signal and processing the filtered and digitized beat signal to determine the level or distance to be measured; a signal generator controlled by the digital processor for generating a test signal; and a switch controllable to connect one of (i) the beat signal and (ii) the test signal to the analog filter; wherein the signal generator is configured to generate the test signal as a periodic waveform signal having a broadband spectrum; and wherein the digital processor is configured to calculate a spectrum of a digitized filtered test signal by Fast Fourier Transform and to generate a fault signal if the calculated spectrum differs from a reference spectrum by a predetermined amount.