Marport M4 - Page 27

M4 - Mx computer System | V2 | Servicing and Maintenance
5.
The spectrum analyzer is displayed. You can display up to 6 spectrum analyzers at the same
time. Below is an example of a page with two spectrum analyzers.
The FFT plot shows three levels of noise in dBV:
1.
RealTime (white): level of noise recorded in real time.
2.
Mean (cyan): mean recorded level of noise. It is useful to assess the noise floor.
3.
Max (dark blue): shows the latest highest level of noise recorded. It is useful to see on which
frequencies are the sensors.
The acceptable average level of noise depends on the conditions (distance from the sensor to
the hydrophone, fishing method, type of hydrophone). You can have better performance with
the following levels:
• Active wideband hydrophone with high/low gain: below -100 dBV
• Active narrowband: NC-1-04 below -80 dBV / NC-1-07 below -100 dBv
• Passive hydrophone: below -110 dBV
6.
Scroll on the frequency or dBV scales to zoom in and out.
7.
Under Peak, you can check:
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