DEPTH DISPLAY DEVICE AND FISH FINDER

摘要

PROBLEM TO BE SOLVED: To provide a depth display device and a fish finder capable of detecting accurately and displaying the depth. SOLUTION: Reception levels (first to third sea bottom levels) of reflected waves from the sea bottom having the different reciprocation number of times of between the sea bottom and the sea level position are acquired, to thereby specify the sea bottom levels of the reflected waves returning via the sea bottom from a transducer, and to determined the depth Ra of the sea bottom. The first to third sea bottom levels are determined through determination processing based on a depth condition (a condition by utilizing the fact that the apparent depths corresponding to the first to third sea bottom levels depend on the reciprocation number of times of a received wave between the sea bottom and the sea level position) and a level difference condition (a condition by utilizing the fact that the difference between the first to third sea bottom levels depends on the reflection number of times of the received wave on the sea bottom and the sea level position).