Title:
UNDERWATER COMMUNICATION SYSTEM
Document Type and Number:
Japanese Patent JP3966089
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an underwater communication system in which communication stability is improved and a communication velocity is accelerated by suppressing an influence of reflection or the like of acoustic signals on a propagation path.
SOLUTION: A receiver 11 converts an acoustic signal propagated under water to an electric signal to produce a received signal 11 and outputs it. A receiving circuit 2 amplifies the received signal 11 which is a weak acoustic-electric signal from the receiver 1, and outputs an AD signal 12 obtained by converting an analog signal to a digital signal. A frequency analytic circuit 3 analyzes a frequency of the AD signal 12 and outputs a frequency analysis output signal 13 resulting from converting a signal of a time area to a signal of a frequency area. A signal detecting circuit 4 detects the presence/non-presence of a start pulse signal within a target frequency band and outputs detection information 14. A code decision circuit 5 decides conditions with respect to the frequency and the time based upon the detection information 14 and the frequency analysis output signal 13 and when the conditions are satisfied, a character code 15 is outputted.
More Like This:
| WO/2024/057231 | UNIVERSAL MULTI-MODE UNDERWATER SOFTWARE DEFINED MODEM |
| WO/2000/045895 | MOUTHPIECE AND SPEAKER ASSEMBLIES FOR UNDERWATER SPEECH |
Inventors:
Koji Goto
Application Number:
JP2002170608A
Publication Date:
August 29, 2007
Filing Date:
June 11, 2002
Export Citation:
Assignee:
NEC
International Classes:
H04B11/00; (IPC1-7): H04B11/00
Domestic Patent References:
| JP62138A | ||||
| JP2003517742A | ||||
| JP6157874A | ||||
| JP62159932A | ||||
| JP2000270030A |
Attorney, Agent or Firm:
Masahiko Desk
Naoki Shimosaka
Yasuhisa Tanizawa
Naoki Shimosaka
Yasuhisa Tanizawa