Catipovic Josko A.

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Catipovic
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Josko A.
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  • Technical Report
    VOICE - a spectrogram computer display package
    (Woods Hole Oceanographic Institution, 1990-07) Martin, Ann ; Catipovic, Josko A. ; Fristrup, Kurt M. ; Tyack, Peter L.
    A real-time spetrogram instrument has been developed to provide an inexpensive and field-portable instrument for the analysis of animal sounds. The instrument integrates a computer graphics display package with a PC-AT computer equipped with an A/D board and a digital signal processing board. It provides a real-time spectrogram display of frequencies up to 50kHz in a variety of modes: a running display, a signal halted on screen, successive expanded views of the signal. The signal amplitude may also be displayed. Portions of the scrolled data may be saved to disk file for future viewing, or as part of a database collection. The screen display may be manipulated to adapt to special needs. Program source listings are included in the text.
  • Technical Report
    Report on the Acoustic Network Arctic Deployment, March 1994
    (Woods Hole Oceanographic Institution, 1995-03) Johnson, Mark ; Herold, David ; Catipovic, Josko A.
    This report describes the March 1994 Arctic deployment undertaken by the Acoustic Telemetry Group of WHOI. The deployment was a part of the 1994 Sea Ice Mechanics Initiative (SIMI) project and was based at the west SIMI camp, approximately 150 nautical miles north-east of Prudhoe Bay, Alaska. The goal of the deployment was to install a network of six high-performance acoustic modems, developed at WHOI, and to obtain a data set demonstrating the communications and acoustic monitoring capabilties of the network. The six modems in the network were deployed over an area of 22 square km and communicated via radio Ethernet with a computer at the SIMI camp. Each model had a global positioning system, an acoustic source and an 8 element receiving array. The network was operated in a round-robin broadcast mode (i.e., each modem in turn transmitted a packet of data while the others received). The transmissions were 5000 bits-per-second QPSK with a 15kHz carrier. An extensive data set including raw acoustic data source localization information, and modem position was collected during the deployment. An additional function of the acoustic network was to communicate with, and track, the Odyssey, an autonomous underwater vehicle operated by the MIT group at the SIMI camp. To this end, the Odyssey was equipped with a Datasonics modem configured for periodic QPSK transmission to the network. A data set was obtained from which both the up-link communication and localization capabilties of the network can be determined.
  • Technical Report
    Multiple convergence zone acoustic telemetry feasibility test report
    (Woods Hole Oceanographic Institution, 1991-11) Catipovic, Josko A. ; von der Heydt, Keith ; Merriam, John Stevens ; Sandsmark, Geir Helge
    This report describes a multiple CZ acoustic telemetry experiment conducted off the coast of California 1/28/90-2/2/90. The goal was to design a maximally robust high speed underwater modem suitable for data telemetry for submerged platforms and moorings. Six modulation methods were used to transmit data at rates from 1 to 1000 baud corresponding to bit rates up to 3kbit/sec. In addition, a large number of channel probe sequences was transmitted in order to estimate channel multipath, fluctuation dynamics and spatial diversity characteristics relevant to acoustic data telemetry. The data was transmitted from a 1 kHz source suspended from the R/V McGaw, and received on a multichannel vertical array tended by the RV Point Sur. The multichannel data was digitally recorded using floating-point digitizers and stored on optical disk for further processing. Approximate transmission ranges were 70, 140, 200 and 250km. Approximtely 8 hrs of transmission were recorded at each data range.
  • Technical Report
    WHOI acoustic telemetry project interim report 12/1/88 - 6/1/89
    (Woods Hole Oceanographic Institution, 1989-07) Catipovic, Josko A. ; Freitag, Lee E.
    This interim report covers the progress of the acoustic telemetry project during the period 12/1/88 to 5/15/89. In general, the work followed the format specified in WHOI proposal No. 5674.1. The major exception was the deletion of the transmitter array development task and a corresponding funding decrease from $242,242 to $170,000. In addition, the period for the funding was extended to June 30, partly due to a two month delay in project startup. The telemetry project was centered around the construction, programming and testing of a digital receiver prototype capable of supporting future signal processing algorithms in real-time over ocean acoustic channels. The baseline receiver consists of a two-channel analog quadrature demodulator, and interface to a multiprocessor receiver for digital signal processing. The software developed includes routines for command and control of the analog demodulator, data handling and formatting, and minimal software to digitally implement an incoherent MFSK demodulator, synchronizer and data decoder. Data storage and display programs were also completed to facilitate the performance analysis of the unit during testing. The system was tested in Woods Hole harbor at data rates up to 4800 bits/sec. The acoustic channel was time-dispersive Rayleigh fading, and performance close to theoretical expectations was achieved. We are confident that the system error behavior is arising from channel-caused effects and known deficiencies in system performance, such as excessive synchronizer steady-state jitter.