JW Fishers SSS-100K PC Operation And Maintenance Manual page 21

The signal (second drawing below) feeds the input of the TVG amp. The TVG amp has been adjusted, by the operator,
to automatically increase the gain over time. The third drawing below shows the gain increase (called the ramp).
Fish
Acoustic Wave
Target #1
10 m
A
m
p
#1
l
i
t
u
d
e
Transmit pulse
G
a
i
Low Gain
n
Transmit pulse
The drawing below shows the output of the TVG amp with the second drawing above applied to the input. When this
signal is printed, there will be a even color across the paper with two dark colors representing the two targets.
A
#1
m
p
l
i
t
u
d Transmit pulse
e
Target #1
100 m Range Switch
Shadow
Shadow
Display
Print Head - Right Channel
fig A
100 m
fig B
8"
fig C
21
Target #2
#2
Shadow
Next transmit pulse
High Gain
Next transmit pulse
#2
Shadow
Next transmit pulse
Target #2