Kongsberg Simrad ST90, Reference Manual

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TVG (Time Variable Gain)
When an acoustic pulse is sent through the water, it will gradually lose its energy. The
greater the distance between the transducer and the target(s), the greater the loss of
energy.
TVG
(Time Variable Gain) compensates for the loss of acoustic energy due to
geometric spread and absorption.
Ping-Ping Filter
The
Ping-Ping Filter
analyses the historical information from previous consecutive
pings in order to remove unwanted noise and interference from the echo presentation.
Pulse Type
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.
Bandwidth
The
Bandwidth
function allows you to select the frequency range in the Hyperbolic
Frequency Modulated (HFM) and Linear Frequency Modulated (LFM) transmissions.
Frequency
The
Frequency
function allows you set the centre frequency for the Hyperbolic
Frequency Modulated (HFM) and Linear Frequency Modulated (LFM) transmissions
(pings), and the operating frequency for the Continuous Wave (CW) pings.
Horizontal TX Sector
In a horizontal swath the ST90 system transmits with the following maximum
horizontal opening angle: 360 degrees. Use the
Horizontal Tx Sector
function to
control the opening angle - and thus the size - of the horizontal search sector (swath).
This is the physical area that is covered with each transmission ("ping").
Vertical TX Sector
The
Vertical Tx Sector
function is used to change the vertical opening angle in
horizontal and vertical swaths.
Range Projection
The distance to a target located anywhere in the water column can be measured in two
ways. This can either be the horizontal distance to the target (
True ), or along the tilt
angle ( Slant ). The
Range Projection
function defines how this distance is measured.
AGC (Automatic Gain Control)
The
AGC
(Automatic Gain Control) function runs an automatic analysis of the echo
strength.
Simrad ST90 Reference Manual