Title:
UNDERWATER COMMUNICATION SYSTEM
Document Type and Number:
WIPO Patent Application WO2002082695
Kind Code:
A3
Abstract:
In a digital acoustic transmission device in which a digital information sequence (31) is electrically modulated (22) on a carrier cos omega t, the modulated carrier (23) is prefaced with at least two pulse signals (24) of known timing relative to each other and to the modulated digital sequence to provide an output signal (13) for acoustic transmission. The pulse signals indicate to receiver the start of a transmission, and contain Doppler information for resampling the modulated signal prior to demodulation. Where the information sequence is in encoded blocks of equal length, the relation between successive blocks can be used to update the Doppler information for use with a following block. Channel information can also be derived from the pulse signals and/or blocks for raking the next part of the incoming signal. Preferably the pulse signals have good correlation characteristics. In the embodiments the pulse signals are an immediately successive identical pair of linearly rising chirps.
Inventors:
DAVIES JONATHAN JAMES (GB)
DUNN SHAUN MICHAEL (GB)
POINTER STEPHEN ARTHUR (GB)
DOWNER SAMUEL WILLIAM (GB)
DUNN SHAUN MICHAEL (GB)
POINTER STEPHEN ARTHUR (GB)
DOWNER SAMUEL WILLIAM (GB)
Application Number:
PCT/GB2002/001510
Publication Date:
February 27, 2003
Filing Date:
March 28, 2002
Export Citation:
Assignee:
QINETIQ LTD (GB)
DAVIES JONATHAN JAMES (GB)
DUNN SHAUN MICHAEL (GB)
POINTER STEPHEN ARTHUR (GB)
DOWNER SAMUEL WILLIAM (GB)
DAVIES JONATHAN JAMES (GB)
DUNN SHAUN MICHAEL (GB)
POINTER STEPHEN ARTHUR (GB)
DOWNER SAMUEL WILLIAM (GB)
International Classes:
H04B11/00; H04B13/02; H04B1/707; H04L1/00; H04L27/10; (IPC1-7): H04B11/00; H04B13/02
Foreign References:
| US5530682A | 1996-06-25 | |||
| US5784339A | 1998-07-21 | |||
| US6125080A | 2000-09-26 |
Download PDF: