DATASONICS SIS-1500 System Manual page 80

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Transmitter board. Transmits the sonar signals.
Receiver board. Receives the sonar signals.
Digitizer board. Converts the received sonar analog signals into a
serial data format.
T1 Interface board. Generates the sonar data telemetry.
Option board. A custom designed board for use with the optional
sensors.
All the boards except the Transmitter and Receiver boards plug directly into
the Backplane board. The Transmitter and Receiver boards connect to the
Backplane board through a wire harness.
The Cable Interface board in the sonar electronics connects directly to the
topside processor's digital multiplexer through the coaxial cable. The inputs
to the Cable Interface board from the topside processor's digital multiplexer
are the high voltage power, the downlink commands, the sonar key, and the
responder key; the outputs from the Cable Interface board to the topside
processor's digital multiplexer are the uplink sonar data, the tow vehicle
status information, and the sensor data. The Cable Interface board filters the
high voltage power from the other signals. In addition, the Cable Interface
board demodulates the sonar and responder keys and converts them into
digital pulses. These pulses key the sonar electronics and the responder,
respectively.
The Power board inputs DC power from the Cable Interface board and
generates regulated +/-12 VDC and +5 VDC power for the sonar electronics
and the standard and optional sensors.
The Modem board inputs the FSK downlink command signals from the Cable
Interface board, demodulates the signals, and converts them into an RS-232
format, which is then output to the Microcontroller board. In addition, the tow
vehicle status and sensor data are output from the Microcontroller board in
RS-232 format to the Modem board, which converts the data into FSK signals
that are output to the Cable Interface board.
The Microcontroller board interfaces with most of the other circuit boards in
the sonar electronics. It provides the Chirp pulse width control, the timing
information and the sonar key to the Burst board; controls the fixed gain, the
time varying gain (TVG), and the diagnostics on the Receiver boards; and
interfaces with the T1 Interface board. The Microcontroller board also
Volume I System Manual
DATASONICS
June 1998