Communications system
An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.
1. An underwater communications system comprising:
an electromagnetic transmitter configured to transmit electromagnetic and/or magnetic signals to a remote receiver, said electromagnetic transmitter comprising a data input and a modulator for modulating input data onto a carrier signal; and
a plurality of electromagnetic transceivers each having a network transmitter and a network receiver, wherein:
at least one of said electromagnetic transmitter and said remote receiver is underwater,
the plurality of electromagnetic transceivers form a mesh network operable to act as a communication path between said electromagnetic transmitter and said remote receiver,
at least a portion of the communication path is underwater, and
the electromagnetic and/or magnetic signals are transmitted via the underwater portion of the communication path.
2. The underwater communications system of claim 1 , wherein said electromagnetic transmitter further comprises an electrically insulated, magnetic coupled antenna for transmitting the electromagnetic signals.
3. The underwater communications system of claim 1 , wherein said data input includes at least one of: a text input; an audio input for capturing audio signals; an image input for capturing an image and a video input for capturing a video image.
4. The underwater communications system of claim 1 , wherein said remote receiver comprises an electrically insulated, magnetic coupled antenna for receiving said electromagnetic and/or magnetic signals and a demodulator for demodulating said electromagnetic and/or magnetic signals.
5. The underwater communications system of claim 1 , wherein each said network transmitter further comprises an electrically insulated, magnetic coupled antenna.
6. The underwater communications system of claim 1 , wherein periodic transmission of data occurs when relevant new data is available at the electromagnetic transmitter.
7. The underwater communications system of claim 1 , wherein periodic transmission of data occurs upon receipt at the electromagnetic transmitter of a send request issued by the remote receiver.
8. The underwater communications system of claim 1 , said electromagnetic transmitter further comprising a digital data compressor for compressing data that is to be transmitted and said remote receiver further comprises a digital data decompressor for decompressing said compressed data.
9. The underwater communications system of claim 1 , wherein said electromagnetic transmitter is operable to transmit signals having a frequency in the range of 1 Hz to 100 MHz.
10. The underwater communications system of claim 1 , wherein at least one of the plurality of electromagnetic transceivers is above water and is operable to pass a signal from said electromagnetic transmitter to said remote receiver through an air propagation path.
11. The underwater communications system of claim 1 , wherein at least one of said plurality of electromagnetic transceivers is mobile.
12. The underwater communications system of claim 1 , wherein at least one of said electromagnetic transmitter and said remote receiver is an above water station.
13. The underwater communications system of claim 12 , wherein said above water station comprises an electrically coupled antenna.
14. The underwater communications system of claim 1 , wherein at least one of said electromagnetic transmitter and said remote receiver includes a device for varying the signal gain.
15. The underwater communications system of claim 1 , wherein said electromagnetic transmitter and said remote receiver are both located underwater, and wherein said electromagnetic and/or magnetic signals follow a signal path which is at least partially an air path that is above water.
16. The underwater communications system of claim 1 , wherein said electromagnetic and/or magnetic signals follow a signal path which is at least partially through a sea bed.
17. An underwater communications system comprising:
at least one transmitter at least one remote receiver and a plurality of transceivers, a first transmitter of said at least one transmitter comprising:
a data input;
a modulator for modulating input data onto a carrier signal; and
an antenna operable to transmit modulated electromagnetic and/or magnetic signals to a remote receiver, and
a first remote receiver of said at least one remote receiver comprising:
an antenna for receiving said modulated electromagnetic and/or magnetic signals, wherein:
at least one of the first transmitter and/or the first remote receiver is underwater,
transmission of data between the first transmitter and the first remote receiver occurs via a mesh network formed of the plurality of transceivers,
at least a portion of a communication path between the first transmitter and/or the first remote receiver is underwater, and
the electromagnetic and/or magnetic signals are transmitted via the underwater portion of the communication path.