On the Ocean Bottom Seismometer Augmentation in the North Pacific Experiment (OBSANP,
June-July, 2013, R/V Melville), a VLA and twelve OBSs were deployed to listen to an active
acoustic source, a J15-3. This report describes the hardware and software used to control and
record the acoustic transmissions from the source. Some significant features of the system are:
1) The system transmits general user-defined source functions, such as M-sequences (.SIO files).
2) In addition to controlling the source waveform, the system also records six real-time channels
in binary files with user-selectable lengths: the monitor hydrophone mounted near the source, the
power amplifier voltage and current, the depth of the source, Vref signal driving the power
amplifiers and an IRIG-B time reference. Files are output in .AUV format with a precision GPSbased
time stamp in the file name. 3) The transmission start time along with ADC and DAC
sample rates are disciplined to GPS time. 4) A convenient, Labview based, user interface
provides real-time source control and monitoring. 5) The software provides parsing and logging
of gyro and GPS NMEA sentences. The system, which was based on an earlier system from
Scripps MPL, worked well on OBSANP and is available for future projects.Funding was provided by the Office of Naval Research
under contract N00014-10-1-0987 and N00014-10-1-0510
