| 摘要 |
PURPOSE:To interpolate data to enhance a measurable maximum flow velocity, by forecasting the next flow velocity on a basis of measured data in the Doppler current meter which measures the flow velocity intermittently with ultrasonic waves. CONSTITUTION:The reflected wave of ultrasonic pulses transmitted from a transmitter 1 and a transducer 2 is amplified by a receiver 3. An output signal R is detected by an orthogonal wave detector 4 and becomes Doppler signals X and Y of the rectangular coordinate system. Coordinates of inputs X and Y are converted to an amplitude (r) and a phase theta of the polar coordinate system by an extension data generating circuit 5. At this time, since signals are obtained discretely synchronously with the pulse transmission, a difference DELTAthetai between the current phase and the preceding phase is obtained. Meanwhile, a phase variance range (Wi+ or -pi) is forecasted on a basis of preceding data, and the difference DELTAthetai is corrected to be within this range, and a correction forecasted variation DELTAthetai' is obtained. Thus, data is interpolated, and the flow velocity is obtained in an analyzer 6. |
