Kongsberg Simrad CP200-5C, Installation Manual

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Wikipedia, Copied September 2013
The signal is the echo that we want to know something about, while the noise is any
unwanted signals or disturbances. The echo must be detected in the noise and therefore
it is necessary to keep the noise level as low as possible in order to obtain high echo
interpretation.
The noise that contributes to the signal to noise ratio may be divided into the following
types of noise:
• Self noise
• Ambient noise
• Electrical noise
• Reverberation
• Underwater noise
• Fishing gear noise
A The transducer can pick up noise from:
• Biological disturbances
• Interference
• Cavitation
• Propeller noise
• Flow noise
• Acoustic noise from other hydroacoustic systems
B The transducer cable is long. Electric noise from generators, pumps, cooling systems
and other electric or electromechanical devices is easily picked up.
C
The preamplifiers are very sensitive. They can easily pick up electrical noise from
internal and external power supplies. The preamplifiers are also vulnerable to analogue
noise created by their own electronic circuitry. Digital noise created by the converter
and processing circuitry can also create noise problems.
Simrad CP200-5C Installation Manual