System Components; Towfish; Sonar Transceiver (Str) - C-Max CM2 User Manual

CM2 Sidescan Sonar User Manual

2. System Components

2. SYSTEM COMPONENTS

Towfish

The towfish is the acoustic sensor head. It transmits a very high frequency acoustic pulse ("ping") at regular
intervals and receives the series of echoes that result from each ping.
Towfish and Tow Cable Terminator
Three types of CM2 towfish are available, namely DF (325/100kHz), EDF (325/780kHz) and HF (325kHz
only). All are identical externally. These are digital towfish, communicating with the surface electronics via
the tow cable.
Optional additional sensors for the towfish are described in Section 22.

Sonar Transceiver (STR)

The "top end" (i.e. surface electronics) unit provides power for the towfish via the tow cable, receives the
echo data and other information such as the towfish altitude, and sends commands to the towfish. The
primary type of top end unit for the CM2 system is the Sonar Transceiver (or STR). As well as
communicating with the towfish, the STR communicates with the PC that acquires, records and displays the
sonar image. Communication with the PC is via the STR's USB interface.
Sonar Transceiver (STR) Versions
Two versions of the STR exist, differing in the type of connectors used and in the DC voltage range that they
accept. The version fitted with MIL-C-5015 connectors accepts 10-28VDC. The alternative version, identified
by its BNC connector, accepts voltages in the range 10-18VDC, with 24VDC as an ordering option. Early
versions also featured an analog output, generated from the internal digital signal, for driving "legacy"
acquisition systems and thermal printers.
Version 3.6 (2008)
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