Jw Fishers Side Scan Sonar Theory Of Operation - JW Fishers SSS-100K PC Operation And Maintenance Manual

JW FISHERS SIDE SCAN SONAR THEORY OF OPERATION

BLOCK DIAGRAM
The key to side scan operation is to understand how the side scan works. We will begin with an overall block
diagram and then discuss the individual components.
Fish
Fish
preamps
transmit Pulse
Transducer
Drivers
When Record is selected, the computer ( Central Processor Unit or CPU ) scans the operator selected settings and sends
a transmit pulse to the transmit electronics in the fish. A short duration 1000 watt pulse is generated to both transducers.
Each transducer produces its own 100Khz or 600Khz sound wave that travels out away from each side of the fish. The
pre-amps in the fish listen to the same transducers for returning echoes. As the sound wave sweeps out across the
bottom, echoes are continuously received by the transducers and amplified by the pre-amps in the fish. The first echo
to be received is the reflection off the bottom directly below the fish. We will only discuss one channel, but what
Fish
follows applies to both channels.
Acoustic Wave
Target #1
10 m
The Fish preamps send the amplified echo signals up the cable to the "time variable gain" (TVG) amplifiers in the Sonar
Processor. The TVG amps increase their gain over time to compensate for signal loss which occurs when the signal
travels through the water. If TVG circuits were not used, then target #1 would display dark, but target #2 would display
very light. Figures below shows the signal with and without the TVG circuits.
A
m
p
#1
l
i
t
u
d
e
Transmit pulse
A
#1
m
p
l
i
t
u
d Transmit pulse
e
Sonar
Processor
TVG
Amplifiers
Interface
100 m Range Switch
Shadow
Shadow
SP to PC Interface
(USB Cable)
board
100 m
Signal without TVG
8"
Signal with TVG
14
Computer
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
CPU 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Left Channel
Target #2
#2
Shadow
Next transmit pulse
#2
Shadow
Next transmit pulse
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Right Channel