Simrad SC90, Installation Manual

Page: 78 / 544

76
419050/B
Acoustic noise
Topics
Introduction to the acoustic noise challenge, page 76
Contributing factors, page 76
Self noise, page 78
Ambient noise, page 80
Electrical self noise, page 81
Reverberation, page 81
Some means to reduce acoustic noise, page 82
Introduction to the acoustic noise challenge
As with any other hydroacoustic systems, the quality of the SC90 echo data and
presentations are subject to unwanted acoustic noise. The echoes from any large and
small target must be detected inside the noise.
It is important that we keep the noise level as low as possible. The is necessary to obtain
long range and dependable interpretations of the echoes.
Even with the advanced noise filtering offered by the SC90, we must address the
noise challenge. This is important during the planning and preparations for the SC90
installation.
Contributing factors
Several factors are contributing to the performance of the hydroacoustic equipment
used on board a vessel.
Factors contributing to the performance of the hydroacoustic equipment used on board a
vessel are:
• The quality and properties of the transmitted signal
• The quality of the receiving system
• The operational settings made during operation
• The properties of the target(s)
• The signal-to-noise ratio
The majority of these factors can neither be controlled nor improved by means
of installation methods or transducer locations. The quality and properties of the
transmitting and receiving systems are key factors during our product development, while
Simrad SC90 Installation Manual