| 摘要 |
An ultrasonic detector of the type used to detect the level of a liquid or the magnitude of liquid flow within a conduit by periodically transmitting ultrasonic energy bursts and receiving echoes therefrom is controlled by a controller with a computer program having a number of routines. The routines include a range search routine that searches a defined range of the detector to locate the targets within the range. The range is searched by repeatedly transmitting energy bursts and gradually decreasing the gain of the detector after the transmission of each burst. All targets identified during the range search are then classified as being either bogus targets or the true target. This classification is made with the use of a bogus buffer in which bogus target data is stored. The detector has a first mode of operation in which the first echo received after the transmission of an energy burst is considered to be the true target and a second mode of operation in which the echo having the largest magnitude is considered to be the true target. The detector identifies the precise time of arrival of an echo by detecting the peak of the echo, which is accomplished by sampling the echo signal at a very high rate and generating digital samples therefrom. The largest digital sample is then identified as corresponding to the echo peak. The detector also includes a gain adjustment routine that allows authorized personnel to adjust the gain of the detector.
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