Koden CVS-702D, Basic Operation Manual

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Chapter 2 Basic operation CVS-702D
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2.1.6 Selection of frequency bandwidth
Frequency bandwidth can be switched to 4 steps: Narrow, Medium, Wide and Fixed. The
change of frequency bandwidth results in change of the resolution of echo sounder and
change of signals in the displayed images. If the frequency bandwidth is wide, the resolution
becomes high. Other way around, if it is narrow, resolution becomes low.
By this nature,
the frequency bandwidth is switched depending on the range: to wide at
shallow range and to narrow at deep range, except for the case of setting at [Fixed].
When frequency bandwidth is switched:
1. For the setup up of frequency bandwidth, based on the setup at [Wide] as reference, at
[Medium], the bandwidth is switched over to the same bandwidth of [Wide] bandwidth that
is 1.5 times of the range used, and at [Narrow], to the minimum bandwidth.
When size of target fish matches the frequency wavelength in use, setup up at [Medium] or
[Narrow] highlights the images and increase visibility. When pulse length is set at [Short]
and frequency bandwidth at [Narrow], response smaller than wavelength is reduced and
noise reduction effect is expected.
2. When frequency bandwidth is setup at [Fixed], the bandwidth is constant regardless of
switching of range.
To select frequency bandwidth:
1. Press [CM] key (lights red) used.
When CM1 is lit red, press [CM1] key .
2. CM menu is displayed.
3. Moving the cursor with , select [Narrow], [Medium], [Wide] or [Fixed] of high
frequency 1 in frequency bandwidth items.
Bandwidth items