| 摘要 |
PROBLEM TO BE SOLVED: To carry out measurement even though the acoustic environment varies, determine a receiving level of a reflected sound wave at every set time during measurement of the one and the same set altitude, by stepwise increasing the sound wave oscillating power if the receiving level is lower than a set level, but by stepwise decreasing the same if it exceeds another set level, successively by several times. SOLUTION: Sound waves having pulse widthsτ1 ,τ2 are radiated aerially from tranceivers in a time-sharing manner by setting a T/ R switch to the transmission side T, and a reflected sound wave (d) reflected from a boundary layer is received by setting the switch to the receiving side R. A measuring altitude is designated by an elapsed time from the time of radiation of the sound wave, and a sampling gate is opened at this time so as to detect a frequency of the received sound wave (d) at the highest level. Thus, a wind direction and a wind velocity at the designated altitude can be obtained from the frequency. After a predetermined time N1 elapses, whether the wind direction and the wind velocity can be calculated or not is checked, and if it is false, the amplification degree is increased by a predetermined value. Thereafter, whether the measurement is made for a time N2 longer than the time N1 or not is determined, and if it is true, the amplification degree is decreased by the predetermined value so as to control the output in consideration with a measuring environment. |
