ULTRASONIC WATER LEVEL MEASUREMENT APPARATUS THAT CAN BE CONTROLLED MULTI FREQUENCY BAND AND WATER LEVEL CONTROL METHOD USING THAT

The present invention provides a water level measuring apparatus using ultrasonic waves, comprising; a detector (6) to transmit and receive ultrasonic waves of a frequency band set according to water level measuring distances; and a converter (4) to measure water levels through ultrasonic waves transmitted and received as well as control transmitting and receiving of ultrasonic waves matching set frequencies on the detector (6); and has effects of being efficient as one converter (4) alone can be applied to various kinds of ultrasonic sensors having a variety of frequency bands, and accordingly being able to save costs for maintenance and repairs upon breakdown of the instrument. In addition, measurement precision can be improved as frequency bands are narrowed down and an unnecessary noise among received signals is reduced by using a digital filter method in an analog filter method. [Reference numerals] (10) Transformer; (12) Output control unit; (14) Control computing unit; (16) Screen display unit; (18) Key control unit; (20) Ultrasonic wave transmission unit; (22) Level receiving unit; (24) Ultrasonic wave transmission/receiving conversion control unit; (6) Detector; (8) Power supply unit