JPH0559383B

A period of a correlation signal from a laser Doppler velocimeter is calculated from crossing points at which a correlation function crosses over a threshold level by clipping and digitizing a Doppler burst signal, thereby enabling an accurate and real time measurement to be made of a flow velocity,...

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Bibliographische Detailangaben
Hauptverfasser:	NAKAJIMA TAKESHI, IKEDA JUJI
Format:	Patent
Sprache:	eng
Schlagworte:	ANALOGOUS ARRANGEMENTS USING OTHER WAVES DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES MEASURING MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION,OR SHOCK MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL METERING BY VOLUME PHYSICS RADIO DIRECTION-FINDING RADIO NAVIGATION TESTING
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Beschreibung
Zusammenfassung:	A period of a correlation signal from a laser Doppler velocimeter is calculated from crossing points at which a correlation function crosses over a threshold level by clipping and digitizing a Doppler burst signal, thereby enabling an accurate and real time measurement to be made of a flow velocity, even in low SNR Doppler signals. Smoothing the waveform of a correlation signal further improves measurement accuracy. When the threshold level is set to be the 1/2 value of the autocorrelation function at tau =0, a crossing point is precisely detected even in an uneven correlation function or small amplitude of the crosscorrelation function, thus further increasing measurement accuracy.