Telemetry system for drill bore holes

Claim 2

A data transmission system for use with a drill string having a length comprising sections in a bore hole within the earth without requiring electrical conductors running the full length of said sections, said system comprising: data input means for generating data signals, transmitting means for transmitting said data signals along at least one section length of said bore hole in a first mode of energy transfer at least first and second spaced apart repeater means located along said bore hole at intervals of at least one of said section lengths, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals at an amplified energy level along at least one section length of said bore hole in a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals at an amplified energy level along at least one section length of said bore hole in said first mode, and receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto.

Claim 3

A data transmission system as in claim 1 wherein said repeater means include means for inverting the phase of information transmitted on any given mode each time that particular mode is retransmitted.

Claim 4

A data transmission system as in claim 1 wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode.

Claim 5

A data transmission system as in claim 3 wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode.

Claim 6

A data transmission system for use in a bore hole in the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals in a first mode of energy transfer, at least first and second spaced apart repeater means, said first repeater means receiving said first mode from said transmitting means and transmitting said data signals on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, and receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, said transmitting means and said first and second repeater means comprising means for transmitting energy through a drill string in said bore hole and the surrounding earth as a transmission medium.

Claim 7

A data transmission system for use in a bore hole in the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals in a first mode of energy transfer, at least first and second spaced apart repeater means, said first repeater means receiving said first mode from said transmitting means and transmitting said data signals on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, and receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, said transmitting means and said first and second repeater means comprising means for transmitting energy through a drill string in said bore hole and the surrounding earth as a transmission medium.

Claim 8

A data transmission system as in claim 5 wherein said first and second repeater means comprise amplification means for providing an amplified output signal on the particular transmission mode involved.

Claim 9

A data transmission system as in claim 6 wherein said first energy transfer mode comprises a magnetic flux along said drill string and said second energy transfer mode comprises an electric current along said drill string and wherein said first and second repeater means comprise means for generating said electric current and said magnetic flux in response to received magnetIc flux and electric current respectively thereby transducing the first to the second mode and vice versa respectively.

Claim 10

A data transmission system as in claim 7 including: toroidal coils for transmitting and receiving the current or second mode, and solenoidal coils for transmitting and receiving the magnetic or first mode, said toroidal and solenoidal coils encompassing at least a portion of said drill string.

Claim 11

A data transmission system as in claim 6 wherein said first energy transfer mode and said second energy transfer mode comprise signals at first and second frequencies and wherein said first and second repeater means comprise means for generating said first and said second frequency in response to receiving said second and said first frequency respectively thereby transducing the first to the second mode and vice versa respectively.

Claim 12

A data transmission system as in claim 9 wherein said repeater means include means for reversing the phase of each frequency with respect to its previous state each time it is retransmitted.

Claim 13

A data transmission system for use in a bore hole in the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals in a first mode of energy transfer, at least first and second spaced apart repeater means, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, and receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, said repeater means including means for inverting the phase of information transmitted on any given mode each time that particular mode is retransmitted, and said transmitting means and said first and second repeater means comprising means for transmitting energy through a drill string in said bore hole and the surrounding earth as a transmission medium.

Claim 14

A data transmission system for use in a bore hole in the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals in a first mode of energy transfer, at least first and second spaced apart repeater means, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, and receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, said repeater means including means for inverting the phase of information transmitted on any given mode each time that particular mode is retransmitted, and said transmitting means and said first and second repeater means comprising means for transmitting energy through a drill string in said bore hole and the surrounding earth as a transmission medium.

Claim 15

A data transmission system as in claim 11 wherein said first and second repeater means comprise amplification means for providing an amplified output signal on the particular transmission mode involved.

Claim 16

A data transmission system as in claim 12 wherein said first energy transfer mode comprises a magnetic flux along said drill string and said second energy transfer mode comprises an electric current along said drill string and wherein said first and second repeater means comprise means for generating said electric current and said magnetic flux in response to received magnetic flux and electric current respectively thereby transducing the first to the second mode and vice versa respectively.

Claim 17

A data transmission system as in claim 13 including: toroidal coils for transmitting and receiving the current or second mode, and solenoidal coils for transmitting and receiving the magnetic or first mode, said toroidal and solenoidal coils encompassing at least a portion of said drill string.

Claim 18

A data transmission system for use in a bore hole in the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals in a first mode of energy transfer, at least first and second spaced apart repeater means, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and selective moDe attenuators inserted in the transmission path at locations occurring after a particular mode has been received and prior to its retransmission on another mode for attenuation of said particular mode.

Claim 19

A data transmission system for use in a bore hole in the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals in a first mode of energy transfer, at least first and second spaced apart repeater means, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and selective moDe attenuators inserted in the transmission path at locations occurring after a particular mode has been received and prior to its retransmission on another mode for attenuation of said particular mode.

Claim 20

A data transmission system as in claim 15 wherein said repeater means include means for inverting the phase of information transmitted on any given mode each time that particular mode is retransmitted.

Claim 21

A data transmission system as in claim 16 for use in a bore hole in the earth, said transmitting means and said first and second repeater means comprising means for transmitting energy through a drill string in said bore hole and the surrounding earth as a transmission medium.

Claim 22

A data transmission system as in claim 17 wherein said first and second repeater means comprise amplification means for providing an amplified output for providing an amplified output signal on the particular transmission mode involved.

Claim 23

A data transmission system as in claim 18 wherein said first energy transfer mode comprise a magnetic flux along said drill string and said second energy transfer mode comprises an electric current along said drill string and wherein said first and second repeater means comprise means for generating said electric current and said magnetic flux in response to received magnetic flux and electric current respectively thereby transducing the first to the second mode and vice versa respectively.

Claim 24

A data transmission system as in claim 19 including: toroidal coils for transmitting and receiving the current or second mode, and solenoidal coils for transmitting and receiving the magnetic or first mode, said toroidal and solenoidal coils encompassing at least a portion of said drill string.

Claim 25

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and including means whereby said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 26

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and including means whereby said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 27

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and wherein said transmitting means and said first and second repeater means include means for causing electromagnetic energy to flow in the drill string in said bore hole and in the surrounding earth.

Claim 28

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and wherein said transmitting means and said first and second repeater means include means for causing electromagnetic energy to flow in the drill string in said bore hole and in the surrounding earth.

Claim 29

A data transmission system as in claim 22 wherein one of either said first or second modes comprises a magnetic flux along said drill string and the other of either said first or second modes comprises an electric current along said Drill string.

Claim 30

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and wherein said transmitting means and said first and second repeater means include means for causing acoustical energy to flow in a drill string within said bore hole.

Claim 31

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and wherein said transmitting means and said first and second repeater means include means for causing acoustical energy to flow in a drill string within said bore hole.

Claim 32

A data transmission system as in claim 24 wherein one of said first and second modes is comprised of a torsional vibration along said drill string, and the other of said first and second modes is comprised of a longitudinal vibration along said drill string.

Claim 33

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means recieving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 34

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means recieving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, and wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 35

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmissions of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, and wherein said transmitting means and said first and second repeater means cause electromagnetic energy to flow in a drill string in said bore hole and in the surrounding earth.

Claim 36

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmissions of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, and wherein said transmitting means and said first and second repeater means cause electromagnetic energy to flow in a drill string in said bore hole and in the surrounding earth.

Claim 37

A data transmission system as in claim 27 wherein one of said first and second modes comprises a magnetic flux along said drill string and the other of said first and second modes comprises an electric circuit along said drill string.

Claim 38

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, and wherein said transmitting means and said first and second repeater means cause acoustical energy to flow in a drill string within said bore hole.

Claim 39

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, and wherein said transmitting means and said first and second repeater means cause acoustical energy to flow in a drill string within said bore hole.

Claim 40

A data transmission system as in claim 29 wherein one of said first and second modes is comprised of a torsional vibration along said drill string and the other of said first and second modes is comprised of a longitudinal vibration along said drill string.

Claim 41

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode, and wherein said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 42

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode, and wherein said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 43

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the laSt repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode, and wherein said transmitting means and said first and second repeater means cause electromagnetic energy to flow in a drill string in said bore hole and in the surrounding earth.

Claim 44

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the laSt repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode, and wherein said transmitting means and said first and second repeater means cause electromagnetic energy to flow in a drill string in said bore hole and in the surrounding earth.

Claim 45

A data transmission system as in claim 32 wherein one of either said first or second modes comprises a magnetic flux along said drill string and the other of either said first or second modes comprises an electric current along said drill string.

Claim 46

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode, and wherein said transmitting means and said first and second repeater means cause acoustical energy to flow in a drill string within said bore hole.

Claim 47

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy transfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissions of said second mode to be phase coherent with the first transmissions of said second mode, wherein said repeater means are arranged to cause the phase of said first mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said first mode, and to cause the phase of said second mode to be reversed on retransmission with respect to the phase of the next earlier transmission of said second mode, and wherein said transmitting means and said first and second repeater means cause acoustical energy to flow in a drill string within said bore hole.

Claim 48

A data transmission system as in claim 34 wherein one of said first and second modes is comprised of a torsional vibration along said drill string, and the other of either said first or second modes is comprised of a longitudinal vibration along said drill string.

Claim 49

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy tranfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissiOns of said second mode to be phase coherent with the first transmissions of said second mode, and wherein at least one of said first and second repeater means contains a sensing device for detecting the existence of positive feedback through the receiver of the next earlier repeater means and a phase adjustment device for adjusting the phase of the output of said at least one repeater means containing said sensing device in such a manner that the feedback between said at least one repeater means and the receiver of said next earlier repeater means will be negative.

Claim 50

A data transmission system for use in a bore hole within the earth comprising: data input means for generating data signals, transmitting means for transmitting said data signals along said bore hole in a first mode of energy tranfer, at least first and second spaced apart repeater means located along said bore hole, said first repeater means receiving said first mode from said transmitting means and retransmitting said data signals along said bore hole on a second mode, said second mode of energy transfer being non-interacting with said first mode, said second repeater means receiving said second mode from said first repeater means and retransmitting said data signals on said first mode, receiving means for receiving and detecting said data signals from at least the last repeater means nearest thereto, wherein said repeater means are arranged to cause all retransmissions of said first mode to be phase coherent with the first transmission of said first mode, and all retransmissiOns of said second mode to be phase coherent with the first transmissions of said second mode, and wherein at least one of said first and second repeater means contains a sensing device for detecting the existence of positive feedback through the receiver of the next earlier repeater means and a phase adjustment device for adjusting the phase of the output of said at least one repeater means containing said sensing device in such a manner that the feedback between said at least one repeater means and the receiver of said next earlier repeater means will be negative.

Claim 51

A data transmission system as in claim 36 wherein said first mode is modulated at a first frequency and said second mode is modulated at a second frequency.

Claim 52

Data transmission system as in claim 36 wherein said transmitting means and said first and second repeater means cause electromagnetic energy to flow in a drill string in said bore hole and in the surrounding earth.

Claim 53

A data transmission system as in claim 38 wherein one of said first and second modes comprises a magnetic flux along said drill string and the other of either said first or second modes comprises an electric current along said drill string.

Claim 54

A data transmission system as in claim 36 wherein said transmitting means and said first and second repeater means cause acoustical energy to flow in a drill string in said bore hole.

Claim 55

A data transmission system as in claim 40 wherein one of said first and second modes is comprised of a torsional vibration along said drill string and the other of said first and second modes is comprised of a longitudinal vibration along said drill string.