CA1087258A - Circuit for wire transmission of high frequency data communication pulse signals - Google Patents
Circuit for wire transmission of high frequency data communication pulse signalsInfo
- Publication number
- CA1087258A CA1087258A CA296,686A CA296686A CA1087258A CA 1087258 A CA1087258 A CA 1087258A CA 296686 A CA296686 A CA 296686A CA 1087258 A CA1087258 A CA 1087258A
- Authority
- CA
- Canada
- Prior art keywords
- coaxial cable
- transceiver
- pulse signals
- delay line
- line
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/14—Two-way operation using the same type of signal, i.e. duplex
- H04L5/16—Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission
Abstract
Abstract A transceiver (transmitter-receiver) for high frequency data pulse signals is connected to a coaxial cable transmission line through a distributed delay line which has an impedance equal in value to the characteristic impedance of the coaxial cable trans-mission line. The transceiver transmitting and receiving circuits are tapped into the transmission line and form a part of the dis-tributed delay line. When not in the transmitting mode, the trans-mitter circuit appears as a reactive element of the distributed delay line and thereby introduces minimum loss or reflection into the transmission line. The transmission line can serve as a trunk line for a number of transceivers by permitting virtually unre-stricted multipoint connections to the line.
Description
Background of the Invention Field of the Invention. This invention is intended for use for high speed data pulse communications via coaxial cable.
It is for use in applications where high data transmission rates must be reliably transmitted over intermediate distances and is particularly adaptable for use in computer system installations.
It is used to interconnect transceivers to enable selective trans-fer of digital data at high data transmission rates between trans-ceivers.
Description of the Prior Art. In one sense, this in-vention can be considered somewhat analogous to digital modems which are used for data communication over telephone linesO How-ever, the difficulties with the latter are in the power losses and the relatively slow speeds at which the data is transferred. The prior art also includes coaxial cable data channel connections between units in a computer system. In those cases, the data rates have been somewhat limited and, even more importantly, it has permitted only a point-to-point connection, i.e., limited to two-connection with a separate coaxial cable being needed to trans-mit digital data information between each two units. Past efforts at implementing multipoint transmission lines of this type have met with only partial success because of the severe loading and distortion introduced when adding more than two transceivers to the coaxial cable.
Summary of the Invention A transceiver for very high data pulse transmission rates is connected into a coaxial cable transmission line by a series of inductances having values and arranged to combine with dis-tributed capacitance to form a delay line having an impedance equal to the characteristic impedance of the coaxial cable so that the connection introduces minimum loss, distortion and reflection into the line. The switching network in the transceiver, for selectively - ~0~7258 setting it to the transmitting mode, and the receiver are tapped into the coaxial cable transmission line through the delay line so that the cable at all times sees only its characteristic im-pedance. The characteristic impedance introduced by the connec-tion of the transceiver into the coaxial cable does not produce any discontinuity nor cause any reflections to occur on the co-axial cable transmission line and permits the transceiver circuits to be tapped into the cable without introducing substantial loss.
Therefore, a number of transceivers can be inserted into the co-axial cable transmission line at various locations along the linewithout substantially affecting the quality of the data pulse sig-nals being transmitted. In this fashion, a single coaxial cable serves as a trunk transmission line to enable virtually unlimited number of transceivers to communicate with one another.
Description of the Drawing Fig. 1 illustrates in block form the manner in which a number of transceivers are connected into a single coaxial cable trunk line under the teachings of the instant invention; and Fig. 2 illustrates in schematic form a preferred embodi-ment of a circuit for connecting a transceiver into the coaxialcable transmission line.
Description of the Preferred Embodiment A single coaxial cable transmission line 10 can serve as a trunk line for interconnecting a plurality of transceivers 11. This is distinguished from the prior art coaxial cable trans-mission lines for communication of high speed pulse data communi-cations which had previously been done point-to-point with a single transceiver on each end of the coaxial cable transmission line.
Referring now to Fig. 2, digital data in high frequency pulse form is fed from a transmitter or data generator, not shown, to terminal 12 into AND gate 13. A transmit enable signal, which may be in the form of a DC voltage level, constitutes the other 10~72~8 input to gate 13 from terminal 14. Gate 13 and the remainder of the electrical circuit can be designed to operate in response to either negative or positive level or going signals but in this instance, and for descriptive purposes only, it is assumed that gate 13 is enabled by a negative level signal. Transistors 15 and 16 are normally in the off condition which results in diodes 17 and 18 being back-biased to the non-conducting condition. When it is desired to permit the transmission of data, the transmit enable signal on terminal 14 goes negative causing transistors 15 and 16 to conduct to remove the back-bias from diodes 17 and 18.
Concurre~tly, gate 13 is enabled so that the data pulses can then pass through gate 13 to transistor 19 through diode 18 and capac-itor 20 along conductor 23 to the junction of inductances 24 and 25 and then to the output line in a manner which will be described.
Typically, the data pulses may range, for example, from 50 mega-cycles or megabits per second to 1 1/2 megabits per second. Data transmission is terminated by causing the signal level at terminal 14 to go more positive thereby disabling or removing the enabling signal from gate 13 and at the same time, cutting off the conduc-tion of transistors 15 and 16. At the same time, the positive going signal is applied through capacitor 21 onto the base of transistor 20 for the purpose of permitting capacitor 20 to re-cover more rapidly than would otherwise be the case.
Inductances 24, 25 and 26 are arranged in a delay line or filter fashion. One end of inductance 24 is connected to co-axial cable 10 through a standard coax cable connector or jack 27; the other end of the inductance 24 is connected to one end of inductance 25; the other end of inductance 25 is connected to one end of inductance 26; and the other end of inductance 26 is connected through another standard coax cable connector or jack 27 to the coaxial cable 10. Line 29 connects the junction of inductances 25 and 26 to the receiver portion of the transceiver, 10~7Z58 not shown. In Fig. 2, capacitances 30, 31, 32 and 33 are illus-trated in shadow line form. Capacitances 30 and 33 represent respectively, in lumped form, the distributed capacitance of coaxial cable connectors and capacitances 31 and 32 respectively represent, also in lumped form, the distributed capacitance asso-ciated with the transmitter and the receiver circuitry. Induc-tances 24, 25 and 26 are wire inductance components having a selec-ted value and arranged in such a manner so that they combine with the distributed capacitances 30, 31, 32 and 33 to form a delay line, as seen by the coaxial cable 10, having an impedance which is equal to the characteristic impedance of the coaxial cable. In a typical case, the characteristic impedance of the coaxial cable i5 in the order of 75 ohms. At the frequencies of transmission with which the instant invention is concerned, inductances 24, 25 and 26 are chosen so that combined with the distributed capaci-tances 30, 31, 32 and 33, the impedance of the delay line circuit appears to the coaxial cable as 75 ohms.
In essence, this delay line arrangement for coupling the receiver and the transmitter of the transceiver to the coaxial cable is such that, in effect, the coaxial cable appears to be uninterrupted and continuous since it introduces no reflections or discontinuities. As illustrated in Fig. 2, the electrical circuit path is from one end of one section of the coaxial cable 10 through jack 27, through the delay line network and through jack 27 to one end of another section of the coaxial cable. The delay line network is then effectiveIy in series with the coaxial cable and for all practical purposes the transmission line is one continuous uninterrupted coaxial cable. The conduction paths to the receiver and transmitter circuits of the transceiver are tapped off the transmission line by conductors 23 and 29 so that the reactive components of the transmitter and receiver circuits ~87Z5~3 form part of the characteristic impedance delay line network so introduce little or no distortion or reflection into the coaxial cable transmission line.
The series inductances 24, 25 and 26 connected between the connectors 27 introduce little loss into the coaxial cable path because the values of the inductances are quite small as a result of the distributed capacitances being quite small. When the transmitter, for example, is in the off condition, the back-bias of diodes 17 and 18 presents a high impedance as seen look-ing into the transceiver from the transmission line through con-ductor 23. Therefore, the transceiver introduces negligible load on the coaxial cable 10. The effect of the delay line network for making the connection to the coaxial cable transmission line is that the coaxial cable 10 appears as a single continuous trans-mission line being tapped off as desired for connection to a plurality of transceivers along the line and, in this fashion, the coaxial cable serves as a trunk line for virtually unlimited number of multiple transceivers which may be closely spaced along the transmission line.
Typically, the transmission line is a BeIdon 8228 Co-axial Cable and the connectors 27 and 28 are standard coaxial cable connectors. Further, typically, the invention satisfac-torily transmits data ranging from a rate of about 50 megabits per second over a coaxial cable transceiver line of about 500 feet in length having about 16 transceivers attached to the coaxial cable trunk line, to a rate of about 1.5 megabits per second over a coaxial cable transmission line about 3,000 feet in length hav-ing up to 64 transceivers connected to the trunk line.
No effort has been made to describe the manner in which the various transceivers are controlled or signaled to transmit or receive since this involves the operation and control of the entire computer system with which these units are used and is not -1~7Z58 pertinent to an understanding of the invention. The types and the values for the circuit components and the electrical signals are considered to be a matter of choice and can be readily deter-mined by one of ordinary skill in the design of circuits of this nature having the benefit of the instant disclosure.
In a typical case, with no limitations thereto being intended, the distributed capacitance 31 and 32 associated res-pectively, with the transmitter and receiver portions of the transceiver may be in the order of about 2 picofarads each, the connector distributed capacitance 30 and 33 may be in the order of one picofarad each, and inductances 24, 25 and 26 are selected to have a value of about lO nano henrys.
It is for use in applications where high data transmission rates must be reliably transmitted over intermediate distances and is particularly adaptable for use in computer system installations.
It is used to interconnect transceivers to enable selective trans-fer of digital data at high data transmission rates between trans-ceivers.
Description of the Prior Art. In one sense, this in-vention can be considered somewhat analogous to digital modems which are used for data communication over telephone linesO How-ever, the difficulties with the latter are in the power losses and the relatively slow speeds at which the data is transferred. The prior art also includes coaxial cable data channel connections between units in a computer system. In those cases, the data rates have been somewhat limited and, even more importantly, it has permitted only a point-to-point connection, i.e., limited to two-connection with a separate coaxial cable being needed to trans-mit digital data information between each two units. Past efforts at implementing multipoint transmission lines of this type have met with only partial success because of the severe loading and distortion introduced when adding more than two transceivers to the coaxial cable.
Summary of the Invention A transceiver for very high data pulse transmission rates is connected into a coaxial cable transmission line by a series of inductances having values and arranged to combine with dis-tributed capacitance to form a delay line having an impedance equal to the characteristic impedance of the coaxial cable so that the connection introduces minimum loss, distortion and reflection into the line. The switching network in the transceiver, for selectively - ~0~7258 setting it to the transmitting mode, and the receiver are tapped into the coaxial cable transmission line through the delay line so that the cable at all times sees only its characteristic im-pedance. The characteristic impedance introduced by the connec-tion of the transceiver into the coaxial cable does not produce any discontinuity nor cause any reflections to occur on the co-axial cable transmission line and permits the transceiver circuits to be tapped into the cable without introducing substantial loss.
Therefore, a number of transceivers can be inserted into the co-axial cable transmission line at various locations along the linewithout substantially affecting the quality of the data pulse sig-nals being transmitted. In this fashion, a single coaxial cable serves as a trunk transmission line to enable virtually unlimited number of transceivers to communicate with one another.
Description of the Drawing Fig. 1 illustrates in block form the manner in which a number of transceivers are connected into a single coaxial cable trunk line under the teachings of the instant invention; and Fig. 2 illustrates in schematic form a preferred embodi-ment of a circuit for connecting a transceiver into the coaxialcable transmission line.
Description of the Preferred Embodiment A single coaxial cable transmission line 10 can serve as a trunk line for interconnecting a plurality of transceivers 11. This is distinguished from the prior art coaxial cable trans-mission lines for communication of high speed pulse data communi-cations which had previously been done point-to-point with a single transceiver on each end of the coaxial cable transmission line.
Referring now to Fig. 2, digital data in high frequency pulse form is fed from a transmitter or data generator, not shown, to terminal 12 into AND gate 13. A transmit enable signal, which may be in the form of a DC voltage level, constitutes the other 10~72~8 input to gate 13 from terminal 14. Gate 13 and the remainder of the electrical circuit can be designed to operate in response to either negative or positive level or going signals but in this instance, and for descriptive purposes only, it is assumed that gate 13 is enabled by a negative level signal. Transistors 15 and 16 are normally in the off condition which results in diodes 17 and 18 being back-biased to the non-conducting condition. When it is desired to permit the transmission of data, the transmit enable signal on terminal 14 goes negative causing transistors 15 and 16 to conduct to remove the back-bias from diodes 17 and 18.
Concurre~tly, gate 13 is enabled so that the data pulses can then pass through gate 13 to transistor 19 through diode 18 and capac-itor 20 along conductor 23 to the junction of inductances 24 and 25 and then to the output line in a manner which will be described.
Typically, the data pulses may range, for example, from 50 mega-cycles or megabits per second to 1 1/2 megabits per second. Data transmission is terminated by causing the signal level at terminal 14 to go more positive thereby disabling or removing the enabling signal from gate 13 and at the same time, cutting off the conduc-tion of transistors 15 and 16. At the same time, the positive going signal is applied through capacitor 21 onto the base of transistor 20 for the purpose of permitting capacitor 20 to re-cover more rapidly than would otherwise be the case.
Inductances 24, 25 and 26 are arranged in a delay line or filter fashion. One end of inductance 24 is connected to co-axial cable 10 through a standard coax cable connector or jack 27; the other end of the inductance 24 is connected to one end of inductance 25; the other end of inductance 25 is connected to one end of inductance 26; and the other end of inductance 26 is connected through another standard coax cable connector or jack 27 to the coaxial cable 10. Line 29 connects the junction of inductances 25 and 26 to the receiver portion of the transceiver, 10~7Z58 not shown. In Fig. 2, capacitances 30, 31, 32 and 33 are illus-trated in shadow line form. Capacitances 30 and 33 represent respectively, in lumped form, the distributed capacitance of coaxial cable connectors and capacitances 31 and 32 respectively represent, also in lumped form, the distributed capacitance asso-ciated with the transmitter and the receiver circuitry. Induc-tances 24, 25 and 26 are wire inductance components having a selec-ted value and arranged in such a manner so that they combine with the distributed capacitances 30, 31, 32 and 33 to form a delay line, as seen by the coaxial cable 10, having an impedance which is equal to the characteristic impedance of the coaxial cable. In a typical case, the characteristic impedance of the coaxial cable i5 in the order of 75 ohms. At the frequencies of transmission with which the instant invention is concerned, inductances 24, 25 and 26 are chosen so that combined with the distributed capaci-tances 30, 31, 32 and 33, the impedance of the delay line circuit appears to the coaxial cable as 75 ohms.
In essence, this delay line arrangement for coupling the receiver and the transmitter of the transceiver to the coaxial cable is such that, in effect, the coaxial cable appears to be uninterrupted and continuous since it introduces no reflections or discontinuities. As illustrated in Fig. 2, the electrical circuit path is from one end of one section of the coaxial cable 10 through jack 27, through the delay line network and through jack 27 to one end of another section of the coaxial cable. The delay line network is then effectiveIy in series with the coaxial cable and for all practical purposes the transmission line is one continuous uninterrupted coaxial cable. The conduction paths to the receiver and transmitter circuits of the transceiver are tapped off the transmission line by conductors 23 and 29 so that the reactive components of the transmitter and receiver circuits ~87Z5~3 form part of the characteristic impedance delay line network so introduce little or no distortion or reflection into the coaxial cable transmission line.
The series inductances 24, 25 and 26 connected between the connectors 27 introduce little loss into the coaxial cable path because the values of the inductances are quite small as a result of the distributed capacitances being quite small. When the transmitter, for example, is in the off condition, the back-bias of diodes 17 and 18 presents a high impedance as seen look-ing into the transceiver from the transmission line through con-ductor 23. Therefore, the transceiver introduces negligible load on the coaxial cable 10. The effect of the delay line network for making the connection to the coaxial cable transmission line is that the coaxial cable 10 appears as a single continuous trans-mission line being tapped off as desired for connection to a plurality of transceivers along the line and, in this fashion, the coaxial cable serves as a trunk line for virtually unlimited number of multiple transceivers which may be closely spaced along the transmission line.
Typically, the transmission line is a BeIdon 8228 Co-axial Cable and the connectors 27 and 28 are standard coaxial cable connectors. Further, typically, the invention satisfac-torily transmits data ranging from a rate of about 50 megabits per second over a coaxial cable transceiver line of about 500 feet in length having about 16 transceivers attached to the coaxial cable trunk line, to a rate of about 1.5 megabits per second over a coaxial cable transmission line about 3,000 feet in length hav-ing up to 64 transceivers connected to the trunk line.
No effort has been made to describe the manner in which the various transceivers are controlled or signaled to transmit or receive since this involves the operation and control of the entire computer system with which these units are used and is not -1~7Z58 pertinent to an understanding of the invention. The types and the values for the circuit components and the electrical signals are considered to be a matter of choice and can be readily deter-mined by one of ordinary skill in the design of circuits of this nature having the benefit of the instant disclosure.
In a typical case, with no limitations thereto being intended, the distributed capacitance 31 and 32 associated res-pectively, with the transmitter and receiver portions of the transceiver may be in the order of about 2 picofarads each, the connector distributed capacitance 30 and 33 may be in the order of one picofarad each, and inductances 24, 25 and 26 are selected to have a value of about lO nano henrys.
Claims (8)
1. Circuitry for use in wire transmission of high frequency data communication pulse signals comprising: first and second lengths of identical coaxial cable; a delay line net-work connecting adjacent ends of said first and second coaxial cable lengths, said delay line network comprising inductance hav-ing a value which combines with distributed capacitance to sub-stantially equal the characteristic impedance of the coaxial cable at the frequency of the data signal; conducting means connected to said delay line network for carrying data signals on the coaxial cable to a receiver; and electrical circuit means connected to said delay line network for selectively feeding transmitted data pulse signals to the coaxial cable.
2. The circuitry as in claim 1 wherein said delay line network includes three inductances in seriatim; said receiver conducting means being connected to one junction of two of the inductances and said electrical circuit means being connected to the other junction of two of the inductances.
3. The invention as set forth in claim 1 wherein said electrical circuit means for selectively feeding transmitted data pulse signals to the coaxial cable includes: distributed capac-itance; a pair of diodes having their opposite electrodes connec-ted together; means coupling the junction of said diode electrodes to said delay line network; switching circuit means connected to the other electrode of one of said diodes for switching said one diode between conducting and non-conducting states; and means for selectively feeding data communication pulse signals to the other electrode of said other diode.
4. The invention as set forth in claim 3 wherein said electrical circuit means further includes means for switching said one diode to the conducting state only when data communication pulse signals are being fed to the electrode of said other diode.
5. For transmission of high frequency data communica-tion pulse signals, in combination: a plurality of at least three substantially identical transceivers, each transceiver having first and second coaxial cable connectors; lengths of identical coaxial cable connected between a coaxial cable connector of one trans-ceiver and a coaxial cable connector of another transceiver; and electrical inductance in each transceiver connected between the coaxial cable connectors in each corresponding transceiver, said inductance being of value and arranged to combine with distributed capacitance of the coaxial cable connectors and circuitry within the transceiver to form a delay line between the coaxial connec-tors having an impedance equal to the characteristic impedance of the coaxial cable at the frequency of the data pulse signals being transmitted, whereby the transmission path through the co-axial cable from transceiver to transceiver appears as an unin-terrupted coaxial cable transmission line.
6. The invention as described in claim 5 further includ-ing electrical conducting means connected to said delay line with-in each transceiver for communicatively tapping into the coaxial cable transmission line.
7. The invention as in claim 6 wherein said inductance comprises three inductors connected in series between the trans-ceiver coaxial cable connectors.
8. The invention as described in claim 7 wherein one electrical conducting means is connected to the junction of two of said inductances for carrying data communication pulse signals from the transceiver transmitter to the coaxial cable and another electrical conducting means is connected to a different junction of two inductances for carrying data communication pulse signals from the coaxial cable to the transceiver receiver.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US768,226 | 1977-02-14 | ||
| US05/768,226 US4086534A (en) | 1977-02-14 | 1977-02-14 | Circuit for wire transmission of high frequency data communication pulse signals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1087258A true CA1087258A (en) | 1980-10-07 |
Family
ID=25081892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA296,686A Expired CA1087258A (en) | 1977-02-14 | 1978-02-10 | Circuit for wire transmission of high frequency data communication pulse signals |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4086534A (en) |
| JP (1) | JPS53121405A (en) |
| CA (1) | CA1087258A (en) |
| DE (1) | DE2806179C2 (en) |
| GB (1) | GB1569755A (en) |
Families Citing this family (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK143627C (en) * | 1978-10-30 | 1982-02-15 | Rovsing A S | WIRELESS CLIP CIRCUIT FOR TRANSMISSION |
| US4270214A (en) * | 1979-03-26 | 1981-05-26 | Sperry Corporation | High impedance tap for tapped bus transmission systems |
| JPS6044854B2 (en) * | 1980-04-22 | 1985-10-05 | 岩崎通信機株式会社 | Signal transmission method |
| US4317205A (en) * | 1980-06-13 | 1982-02-23 | Tcl, Inc. | Wideband transceiver with EMI suppression |
| USRE31638E (en) * | 1980-06-13 | 1984-07-31 | Tcl, Inc. | Wideband transceiver with EMI suppression |
| US4425663A (en) * | 1980-06-13 | 1984-01-10 | Tcl, Inc. | Low input capacitance data network transceiver |
| NL8005458A (en) * | 1980-10-02 | 1982-05-03 | Philips Nv | COMMUNICATION SYSTEM AND STATION SUITABLE FOR THIS. |
| US4408353A (en) * | 1980-10-17 | 1983-10-04 | Amp Incorporated | Coaxial cable/fiber optic bus network |
| US4443884A (en) * | 1982-03-18 | 1984-04-17 | Protocol Computers, Inc. | Data line interface |
| US4608559A (en) * | 1982-08-19 | 1986-08-26 | Computer Automation, Inc. | Local modulated carrier data network with a collision avoidance protocol |
| US4481641A (en) * | 1982-09-30 | 1984-11-06 | Ford Motor Company | Coaxial cable tap coupler for a data transceiver |
| US4630284A (en) * | 1984-12-28 | 1986-12-16 | Gte Laboratories Incorporated | Low power line driving digital transmission system |
| US4754477A (en) * | 1985-02-18 | 1988-06-28 | Tamura Electric Works, Ltd. | Key telephone system |
| US4789860A (en) * | 1985-03-12 | 1988-12-06 | U.S. Philips Corp. | Interface between a receiver and a sub-system |
| US4829244A (en) * | 1985-07-05 | 1989-05-09 | Data Switch Corporation | Bus and tag cable monitoring tap |
| US4725836A (en) * | 1986-01-27 | 1988-02-16 | Snap Systems, Inc. | Series port connection of a plurality of terminals to a master processor |
| US4736385A (en) * | 1987-01-27 | 1988-04-05 | Computer Network Technology Corporation | Transmitter and receiver circuit |
| DE3715594C2 (en) * | 1987-05-09 | 1994-07-14 | Broadcast Television Syst | Arrangement for connecting output and input stages of a transceiver |
| US5125006A (en) * | 1989-12-08 | 1992-06-23 | Standard Microsystems Corporation | Local area network high impedance transceiver |
| US5448591A (en) * | 1990-06-24 | 1995-09-05 | Next, Inc. | Method and apparatus for clock and data delivery on a bus |
| US5654984A (en) * | 1993-12-03 | 1997-08-05 | Silicon Systems, Inc. | Signal modulation across capacitors |
| JPH10224270A (en) * | 1997-02-03 | 1998-08-21 | Mitsubishi Electric Corp | Transmission reception system |
| US6011952A (en) * | 1998-01-20 | 2000-01-04 | Viasat, Inc. | Self-interference cancellation for relayed communication networks |
| US6859641B2 (en) * | 2001-06-21 | 2005-02-22 | Applied Signal Technology, Inc. | Adaptive canceller for frequency reuse systems |
| US6907093B2 (en) * | 2001-08-08 | 2005-06-14 | Viasat, Inc. | Method and apparatus for relayed communication using band-pass signals for self-interference cancellation |
| US6725017B2 (en) | 2001-12-05 | 2004-04-20 | Viasat, Inc. | Multi-channel self-interference cancellation method and apparatus for relayed communication |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3516065A (en) * | 1967-01-13 | 1970-06-02 | Ibm | Digital transmission system |
| US3585595A (en) * | 1969-09-05 | 1971-06-15 | Instrument Systems Corp | Closed loop control system having series connected coders |
| US3632881A (en) * | 1970-03-16 | 1972-01-04 | Ibm | Data communications method and system |
| US3744051A (en) * | 1971-08-31 | 1973-07-03 | Computer Transmission Corp | Computer interface coding and decoding apparatus |
| JPS4924176U (en) * | 1972-05-31 | 1974-03-01 | ||
| FR2199920A5 (en) * | 1972-06-16 | 1974-04-12 | Materiel Telephonique | |
| US3786419A (en) * | 1972-12-26 | 1974-01-15 | Ibm | Synchronizing clock system for a multi-terminal communication apparatus |
| GB1448099A (en) * | 1973-12-13 | 1976-09-02 | Ibm | Digital signal transmission system for minimising the effects of reflections |
| US3993867A (en) * | 1974-10-15 | 1976-11-23 | Motorola, Inc. | Digital single signal line full duplex method and apparatus |
| JPS5918727Y2 (en) * | 1974-11-27 | 1984-05-30 | ソニー株式会社 | signal distribution device |
| US4063220A (en) * | 1975-03-31 | 1977-12-13 | Xerox Corporation | Multipoint data communication system with collision detection |
-
1977
- 1977-02-14 US US05/768,226 patent/US4086534A/en not_active Expired - Lifetime
-
1978
- 1978-02-10 CA CA296,686A patent/CA1087258A/en not_active Expired
- 1978-02-14 GB GB5827/78A patent/GB1569755A/en not_active Expired
- 1978-02-14 JP JP1585478A patent/JPS53121405A/en active Granted
- 1978-02-14 DE DE2806179A patent/DE2806179C2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1569755A (en) | 1980-06-18 |
| DE2806179C2 (en) | 1986-02-20 |
| JPS6336178B2 (en) | 1988-07-19 |
| US4086534A (en) | 1978-04-25 |
| DE2806179A1 (en) | 1978-08-17 |
| JPS53121405A (en) | 1978-10-23 |
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| JPS636925A (en) | Communication equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |