Kongsberg Simrad ST90, Reference Manual

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Pulse Type function
The
Pulse Type
function allows you to select the "shape" of the transmitted pulses ("pings").
Different shapes have different qualities. Which pulse type to use depends on the current
environmental conditions, your range to the target(s) and the type and speed of the target(s)
you are observing.
How to open
You open this function from the
Active
menu.
Description
The ST90 system offers several pulse types:
• CW (Continuous Wave)
• LFM (Linear Frequency Modulation)
• HFM (Hyperbolic Frequency Modulation)
Note
HFM (Hyperbolic Frequency Modulation) is only available if your transceiver is fitted with
LPT32 transceiver boards. To use the pulse type, you must make changes to the setup files.
To find out which transceiver boards your transceiver is fitted with, see the
Transceiver
page in the
Diagnostics
dialog box.
For each pulse type you can select Short , Normal or Long . These options define the pulse
duration. This is the current duration ("length") of the transmitted pulse. Use the
Frequency
function to define the centre frequency used by the transmitted pulse. Use the
Bandwidth
function to define the frequency range during the transmission.
Note
The choice you make is by default only applied to the currently selected (active) view. Before
you can change the settings related to a view, you must click inside the view to activate it.
There are no specific procedures that tell you exactly when to use which pulse type. The
use of this function depends largely on the range you use to study your target(s), how the
target(s) behave, and the current environmental conditions.
Simrad ST90 Reference Manual