Kolida SDE-28S, Руководство пользователя

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Fig.3-9 Device setting
Ⅰ
, Survey Mode Setting, there are auto and manual for option.
Ⅱ
, Transmitted intensity, it includes the adjust of pulse length and blanking.
Pulse length
, pulse length indicates the transmitted pulse duration with the millisecond unit,
and its value ranges from 0.01 to 1.2. The intensity of the transmitted pulse becomes stronger
along with longer pulse.
The figure width of the transmitted / received pulse means the pulse
intensity, and the figure length of the transmitted / received pulse means the pulse length.
If the pulse length is too long, the signal duration is too long, it may cause the error because of
the overlap of the transmitted pulse and the echo wave when measure in shallow water.
If the pulse length is too short, then the signal duration time is too short, when measure in deep
water or the absorption power of the water is too strong, may appear no echo because the
transducer can’t receive strong enough echo signal. So, we should adjust the pulse length value
according to depth real time. The default value of pulse length is 0.1ms. If we work on the sea,
we should increase the pulse length properly, since the higher salinity water absorbs ultrasound
strongly.
Blanking
, the experiment proves that the ultrasonic lasts out even if the Pulse Length time is
over, and that is said remaining ultrasonic signal. And this signal will affect the return signal from
the bottom, and the blanking pulse length can clear the remaining signal to get precise depth.