Ninglu DS207, Operation & Installation Manual

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2
Working Principle
Working Principle of the Sounder
Screen Display
The ultrasonic wave is sent and received repeatedly by the sounder. The latest echo
is recorded as a line on the far right of the screen. The image is consisting of the
moving-to- left echo.
The acoustic velocity is 340m/s in the air and 1,500m/s
in the water. The acoustic time is one second during the
round-trip distance of the underwater 750m. So, the
target depth can be calculated by measuring the
round-trip time of acoustic wave (Fig. 1).
Due to ultrasonic frequency is higher than that of the
sound waves by human-ear hearing, ultrasonic is
suitable for underwater detection. The ultrasonic
transducer of the sounder can launch and receives the
ultrasonic wave. Through recording, the underwater
target is displayed on the LCD screen and the water
depth is calculated for display.
The discontinuous yellow line is the
time scale of 30 seconds. Under the
time scale, the horizontal line is the
transmitting wave. Shown in Fig. 2, the
three spot may be the shoal. Under shoal,
there are the water-button wave and
second-trace echo, which depth is the
twice of the water-button wave depth. The
water button is harder, the echo is
stronger and thicker.
Fig. 1
Fig. 2