WO1997023058A1 - Power line communications system with driver circuit - Google Patents
Power line communications system with driver circuit Download PDFInfo
- Publication number
- WO1997023058A1 WO1997023058A1 PCT/US1996/020171 US9620171W WO9723058A1 WO 1997023058 A1 WO1997023058 A1 WO 1997023058A1 US 9620171 W US9620171 W US 9620171W WO 9723058 A1 WO9723058 A1 WO 9723058A1
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- WO
- WIPO (PCT)
- Prior art keywords
- signals
- transistors
- frequency range
- operating frequency
- roll
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
- H04B3/56—Circuits for coupling, blocking, or by-passing of signals
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
- H03F3/3069—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the emitters of complementary power transistors being connected to the output
- H03F3/3076—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the emitters of complementary power transistors being connected to the output with symmetrical driving of the end stage
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5429—Applications for powerline communications
- H04B2203/5437—Wired telephone
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5429—Applications for powerline communications
- H04B2203/5441—Wireless systems or telephone
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5429—Applications for powerline communications
- H04B2203/545—Audio/video application, e.g. interphone
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5462—Systems for power line communications
- H04B2203/5483—Systems for power line communications using coupling circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5462—Systems for power line communications
- H04B2203/5491—Systems for power line communications using filtering and bypassing
Definitions
- the present invention relates, in general, to power line communications systems and, in particular, to a driver circuit especially useful in a power line communications systems.
- the signals which are to be conducted along the power line are amplified by a driver circuit composed of a driver amplifier and a bandpass filter and the amplified signals are conducted to the power line through a coupler.
- the driver circuit presents a low output impedance, supplies a low output current, and conducts to the coupler only the signals of interest, namely the signals within the frequency band of the signals of interest.
- the frequency discrimination requirement is particularly important when the power line is used to conduct different types of information signals, such as television, audio, telephone and computer, in different frequency bands so that information signals of one type do not interfere with information signals of another type.
- the common practice in systems of this type is to include in the transmitter unit (i.e. the unit which introduces the signals of interest onto the power line) and bandpass filter and to pass the signals of interest through the bandpass filter, prior to amplification, so that only the signals of interest are amplified and conducted to the power line and undesired signals are not amplified nor conducted to the power line.
- the bandpass filtering is accomplished by inductors and capacitors arranged as a filter.
- the present invention utilizes the operating frequency range of transistors arranged in the driver amplifier and selected for the particular application to permit the passage of the signals of interest within the operating frequency range of the transistors and prevent the passage and generation of undesired signals having a frequency outside the operating frequency range of the transistors.
- inductors and capacitors which otherwise would be included to provide the desired filtering effect, are not needed, thereby reducing cost and saving space.
- the amplifying and filtering functions can be arranged on an integrated circuit chip.
- a power line communications system constructed in accordance with the present invention, includes means for supplying different information signals within different frequency ranges and a power line along which the information signals are conducted.
- the transmitter unit includes a driver circuit to which the selected information signals are supplied and has a driver amplifier having a pair of transistors in push-pull arrangement with each of said transistors having a defined operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals having a frequency outside the operating frequency range of the transistors.
- the defined operating frequency range of the transistors includes a roll-on portion, a roll-off portion, and a substantially flat portion between the roll-on portion and the roll-off portion and which corresponds to the frequency range of the selected information signals.
- the driver circuit also has a bandpass filter to which signals from the driver amplifier are conducted and has a pass band which prevents signals having a frequency within the roll-on portion of the defined operating frequency range of the transistors from passing, permits signals having a frequency within the flat portion of the defined operating frequency range of the transistors to pass, and prevents signals having a frequency within the roll-off portion of the defined operating frequency range of the transistors from passing.
- the transmitter unit further includes a coupler for conducting the selected information signals passed by the bandpass filter of the driver circuit to the power line.
- FIG. 1 is a circuit diagram of a power line communications system constructed in accordance with the present invention. - 3 -
- Figure 2 shows typical output frequency response characteristics for the driver amplifier and bandpass filter of the driver circuit of a power line communications system constructed in accordance with the present invention used for the transmission and reception of television signals.
- a power line communications system constructed in accordance with the present invention, includes means for supplying different information signals within different frequency ranges.
- such means include a first source of information signals, such as an antenna or cable box which is represented by reference numeral 10 and from which television signals are supplied, and a second source of information signals, such as a computer which is represented by reference numeral 11 and from which computer signals are supplied.
- a power line communications system constructed in accordance with the present invention, can also be used to conduct other types of signals, such as audio and telephone signals.
- a power line communications system constructed in accordance with the present invention, also includes a power line 12 along which the information signals are conducted.
- a power line 12 along which the information signals are conducted.
- the means by which the different information signals are conducted to power line 12 must be arranged so that information signals of one sort do not interfere with information signals of another sort.
- a power line communications system constructed in accordance with the present invention, further includes a transmitter unit 14 for conducting selected ones of the information signals to power line 12 and a receiver unit 16 for receiving the selected information signals conducted along the power line.
- Transmitter unit 14 includes an amplifier and shaper 17 a driver circuit to which the selected information signals are supplied.
- the driver circuit includes a driver amplifier 18 having a pair of transistors 20 and 22 in push-pull arrangement with each of the transistors having a defmed operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals having a frequency outside the operating frequency range of the transistors.
- Driver amplifier 18 can be arranged as a class B driver or a class AB driver.
- the defined operating frequency range of transistors 20 and 22, indicated by the dashed line curve includes a roll-on portion, a roll-off portion, and a substantially flat portion between the roll-on portion and the roll-off portion and which corresponds to the frequency range of the selected information signals.
- the frequency response characteristic has a roll-on portion which extends to approximately 12.5 MHz, a roll-off portion which extends from approximately 25 MHz, and a substantially flat portion which extends from approximately 12.5 MHz to approximately 25 MHz.
- the driver circuit also includes a bandpass filter 24 to which signals from driver amplifier 18 are conducted and has a pass band which prevents signals having a frequency within the roll-on portion of the defined operating frequency range of transistors 20 and 22 from passing, permits signals having a frequency within the flat portion of the defined operating frequency range of transistors 20 and 22 to pass, and prevents signals having a frequency within the roll-off portion of the defined operating frequency range of transistors 20 and 22 from passing.
- bandpass filter 24 sharpens the frequency characteristic of the driver circuit to reduce the ranges of the roll-on portion and the roll- off portion of the frequency characteristic of the driver circuit by a steeper rise in the roll- on portion of the frequency characteristic and a steeper drop in the roll-off portion of the frequency characteristic. This is indicated by the solid line curve of Figure 2.
- Transmitter unit 14 also includes a coupler 26 for conducting the selected information signals passed by bandpass filter 24 of the driver circuit to power line 12. As shown in Figure 1 , coupler 26 is connected to power line 12 by means of a plug 28 which is inserted into an outlet 30 of the power line.
- Receiver unit 16 receives the selected information signals conducted along power line 12 by means of a coupler 32 which is connected by a plug 34 to an outlet 36 of the power line. Receiver unit 16 also includes a bandpass filter 38 which is tuned to the frequency range of the selected information signals to pass the selected information signals to an amplifier and shaper 40 to which a television set 42 is connected for viewing the selected information signals received by receiver unit 16.
- Transmitter unit 44 is arranged similar to transmitter 14 with (1) a driver amplifier having a pair of transistors in push-pull arrangement with each of the transistors having a defined operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals having a frequency outside the operating frequency range of the transistors, and (2) a bandpass filter to which signals from the driver amplifier are conducted and having a pass band which (i) prevents signals having a frequency within the roll-on portion of the defined operating frequency range of the transistors from passing, (ii) permits signals having a frequency within the flat portion of the defined operating frequency range of the transistors to pass, and (iii) prevents signals having a frequency within the roll-off portion of the defined operating frequency range of the transistors from passing.
- Another receiver unit (not shown), adapted to receive the information signals conducted to power line 12 by transmitter unit 44, would be connected to the power
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
Abstract
A power line communications system having a driver circuit which includes a driver amplifier (18) and a bandpass filter (24). The driver amplifier has a pair of transistors (20, 22) in push-pull arrangement with each of the transistors having a defined operating frequency range which prevents passage and generation of signals having a frequency outside the operating frequency range of the transistors. The bandpass filter to which signals from the driver amplifier are conducted has a pass band which (a) prevents signals having a frequency within the roll-on portion of the defined operating frequency range of the transistors from passing, (b) permits signals having a frequency within the flat portion of the defined operating frequency range of the transistors to pass, and (c) prevents signals having a frequency within the roll-off portion of the defined operating frequency range of the transistors from passing.
Description
POWER LINE COMMUNICATIONS SYSTEM WITH DRIVER CIRCUIT
TECHNICAL FIELD
The present invention relates, in general, to power line communications systems and, in particular, to a driver circuit especially useful in a power line communications systems. BACKGROUND OF THE INVENTION
In power line communications systems, the signals which are to be conducted along the power line are amplified by a driver circuit composed of a driver amplifier and a bandpass filter and the amplified signals are conducted to the power line through a coupler. It is important that the driver circuit presents a low output impedance, supplies a low output current, and conducts to the coupler only the signals of interest, namely the signals within the frequency band of the signals of interest. The frequency discrimination requirement is particularly important when the power line is used to conduct different types of information signals, such as television, audio, telephone and computer, in different frequency bands so that information signals of one type do not interfere with information signals of another type.
The common practice in systems of this type is to include in the transmitter unit (i.e. the unit which introduces the signals of interest onto the power line) and bandpass filter and to pass the signals of interest through the bandpass filter, prior to amplification, so that only the signals of interest are amplified and conducted to the power line and undesired signals are not amplified nor conducted to the power line. The bandpass filtering is accomplished by inductors and capacitors arranged as a filter.
SUMMARY OF THE INVENTION
The present invention utilizes the operating frequency range of transistors arranged in the driver amplifier and selected for the particular application to permit the passage of the signals of interest within the operating frequency range of the transistors and prevent the passage and generation of undesired signals having a frequency outside the operating
frequency range of the transistors. As a result, inductors and capacitors, which otherwise would be included to provide the desired filtering effect, are not needed, thereby reducing cost and saving space. In addition, the amplifying and filtering functions can be arranged on an integrated circuit chip. A power line communications system, constructed in accordance with the present invention, includes means for supplying different information signals within different frequency ranges and a power line along which the information signals are conducted. Also included in the power line communications system are a transmitter unit for conducting selected ones of the information signals to the power line and a receiver unit for receiving the selected information signals conducted along the power line. The transmitter unit includes a driver circuit to which the selected information signals are supplied and has a driver amplifier having a pair of transistors in push-pull arrangement with each of said transistors having a defined operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals having a frequency outside the operating frequency range of the transistors. The defined operating frequency range of the transistors includes a roll-on portion, a roll-off portion, and a substantially flat portion between the roll-on portion and the roll-off portion and which corresponds to the frequency range of the selected information signals. The driver circuit also has a bandpass filter to which signals from the driver amplifier are conducted and has a pass band which prevents signals having a frequency within the roll-on portion of the defined operating frequency range of the transistors from passing, permits signals having a frequency within the flat portion of the defined operating frequency range of the transistors to pass, and prevents signals having a frequency within the roll-off portion of the defined operating frequency range of the transistors from passing. The transmitter unit further includes a coupler for conducting the selected information signals passed by the bandpass filter of the driver circuit to the power line.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 is a circuit diagram of a power line communications system constructed in accordance with the present invention.
- 3 -
Figure 2 shows typical output frequency response characteristics for the driver amplifier and bandpass filter of the driver circuit of a power line communications system constructed in accordance with the present invention used for the transmission and reception of television signals. DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, a power line communications system, constructed in accordance with the present invention, includes means for supplying different information signals within different frequency ranges. For the embodiment of the invention illustrated in Figure 1 , such means include a first source of information signals, such as an antenna or cable box which is represented by reference numeral 10 and from which television signals are supplied, and a second source of information signals, such as a computer which is represented by reference numeral 11 and from which computer signals are supplied. A power line communications system, constructed in accordance with the present invention, can also be used to conduct other types of signals, such as audio and telephone signals.
A power line communications system, constructed in accordance with the present invention, also includes a power line 12 along which the information signals are conducted. As will be explained, the means by which the different information signals are conducted to power line 12 must be arranged so that information signals of one sort do not interfere with information signals of another sort.
A power line communications system, constructed in accordance with the present invention, further includes a transmitter unit 14 for conducting selected ones of the information signals to power line 12 and a receiver unit 16 for receiving the selected information signals conducted along the power line. Transmitter unit 14 includes an amplifier and shaper 17 a driver circuit to which the selected information signals are supplied. The driver circuit includes a driver amplifier 18 having a pair of transistors 20 and 22 in push-pull arrangement with each of the transistors having a defmed operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals
having a frequency outside the operating frequency range of the transistors. Driver amplifier 18 can be arranged as a class B driver or a class AB driver.
As shown in Figure 2, the defined operating frequency range of transistors 20 and 22, indicated by the dashed line curve, includes a roll-on portion, a roll-off portion, and a substantially flat portion between the roll-on portion and the roll-off portion and which corresponds to the frequency range of the selected information signals. For the transmission and reception of television signals, the frequency response characteristic has a roll-on portion which extends to approximately 12.5 MHz, a roll-off portion which extends from approximately 25 MHz, and a substantially flat portion which extends from approximately 12.5 MHz to approximately 25 MHz.
The driver circuit also includes a bandpass filter 24 to which signals from driver amplifier 18 are conducted and has a pass band which prevents signals having a frequency within the roll-on portion of the defined operating frequency range of transistors 20 and 22 from passing, permits signals having a frequency within the flat portion of the defined operating frequency range of transistors 20 and 22 to pass, and prevents signals having a frequency within the roll-off portion of the defined operating frequency range of transistors 20 and 22 from passing. In effect, bandpass filter 24 sharpens the frequency characteristic of the driver circuit to reduce the ranges of the roll-on portion and the roll- off portion of the frequency characteristic of the driver circuit by a steeper rise in the roll- on portion of the frequency characteristic and a steeper drop in the roll-off portion of the frequency characteristic. This is indicated by the solid line curve of Figure 2.
Transmitter unit 14 also includes a coupler 26 for conducting the selected information signals passed by bandpass filter 24 of the driver circuit to power line 12. As shown in Figure 1 , coupler 26 is connected to power line 12 by means of a plug 28 which is inserted into an outlet 30 of the power line.
Receiver unit 16 receives the selected information signals conducted along power line 12 by means of a coupler 32 which is connected by a plug 34 to an outlet 36 of the power line. Receiver unit 16 also includes a bandpass filter 38 which is tuned to the frequency range of the selected information signals to pass the selected information
signals to an amplifier and shaper 40 to which a television set 42 is connected for viewing the selected information signals received by receiver unit 16.
Information signals from computer 11 are conducted to power line 12 by a transmitter unit 44 which is connected to the power line by a plug 46 and an outlet 48 of the power line. Transmitter unit 44 is arranged similar to transmitter 14 with (1) a driver amplifier having a pair of transistors in push-pull arrangement with each of the transistors having a defined operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals having a frequency outside the operating frequency range of the transistors, and (2) a bandpass filter to which signals from the driver amplifier are conducted and having a pass band which (i) prevents signals having a frequency within the roll-on portion of the defined operating frequency range of the transistors from passing, (ii) permits signals having a frequency within the flat portion of the defined operating frequency range of the transistors to pass, and (iii) prevents signals having a frequency within the roll-off portion of the defined operating frequency range of the transistors from passing. Another receiver unit (not shown), adapted to receive the information signals conducted to power line 12 by transmitter unit 44, would be connected to the power line to receive the information signals supplied by computer 11.
While there have been described preferred embodiments of the present invention, it should be obvious to those skilled in the art that various modifications and changes can be made without departing from the true spirit and scope of the invention.
Claims
What is Claimed: 1. A power line communications system comprising: means for supplying different information signals within different frequency ranges; a power line along which the information signals are conducted; a transmitter unit for conducting selected ones of the information signals to said power line and including: (a) a driver circuit to which the selected information signals are supplied and including: (1) a driver amplifier having a pair of transistors in push-pull arrangement with each of said transistors having a defined operating frequency range which includes the frequency range of the selected information signals and prevents passage and generation of signals having a frequency outside the operating frequency range of said transistors, the defined operating frequency range of said transistors including: (i) a roll-on portion, (ii) a roll-off portion, and (iii) a substantially flat portion between the roll-on portion and the roll-off portion and which corresponds to the frequency range of the selected information signals, and (2) a bandpass filter to which signals from said driver amplifier are conducted and having a pass band which: (i) prevents signals having a frequency within the roll-on portion of the defined operating frequency range of said transistors from passing, (ii) permits signals having a frequency within the flat portion of the defined operating frequency range of said transistors to pass, and (iii) prevents signals having a frequency within the roll-off portion of the defined operating frequency range of said transistors from passing; (3) a coupler for conducting the selected information signals passed by said bandpass filter of said driver circuit to said power line; and a receiver unit for receiving said selected information signals conducted along said power line.
2. A power line communications system according to claim 1 wherein said driver amplifier is one of a class B driver and a class AB driver.
3. A driver circuit comprising: a driver amplifier having a pair of transistors in push-pull arrangement with each of said transistors having a defined operating frequency range which prevents passage and generation of signals having a frequency outside the operating frequency range of said transistors, the defined operating frequency range of said transistors including: (a) a roll-on portion,
(b) a substantially flat portion, and
(c) a roll-off portion; and
a bandpass filter to which signals from said driver amplifier are conducted and having a pass band which: (a) prevents signals having a frequency within the roll-on portion of the defined operating frequency range of said transistors from passing,
(b) permits signals having a frequency within the flat portion of the defined operating frequency range of said transistors to pass, and (c) prevents signals having a frequency within the roll-off portion of the defined operating frequency range of said transistors from passing.
4. A driver circuit according to claim 3 wherein said driver amplifier s B driver and a class AB driver.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU14255/97A AU1425597A (en) | 1995-12-19 | 1996-12-18 | Power line communications system with driver circuit |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US889195P | 1995-12-19 | 1995-12-19 | |
| US60/008,891 | 1995-12-19 | ||
| US08/766,064 | 1996-12-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1997023058A1 true WO1997023058A1 (en) | 1997-06-26 |
Family
ID=21734293
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1996/020171 WO1997023058A1 (en) | 1995-12-19 | 1996-12-18 | Power line communications system with driver circuit |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU1425597A (en) |
| WO (1) | WO1997023058A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001080440A1 (en) * | 2000-04-12 | 2001-10-25 | Power Line Networks | Transmission system and method for power line communication |
| US8184014B2 (en) | 2008-06-27 | 2012-05-22 | Schlumberger Technology Corporation | Driver to transmit signals over a transmission line in a well |
| WO2015176381A1 (en) * | 2014-05-21 | 2015-11-26 | 瑞斯康微电子（深圳）有限公司 | Power line carrier power amplification circuit |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4879522A (en) * | 1987-08-22 | 1989-11-07 | Telefunken Electronic Gmbh | Integrated complementary push-pull B final stage |
| US5241283A (en) * | 1992-07-30 | 1993-08-31 | Echelon Corporation | Drive amplifier for power line communications |
-
1996
- 1996-12-18 AU AU14255/97A patent/AU1425597A/en not_active Abandoned
- 1996-12-18 WO PCT/US1996/020171 patent/WO1997023058A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4879522A (en) * | 1987-08-22 | 1989-11-07 | Telefunken Electronic Gmbh | Integrated complementary push-pull B final stage |
| US5241283A (en) * | 1992-07-30 | 1993-08-31 | Echelon Corporation | Drive amplifier for power line communications |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001080440A1 (en) * | 2000-04-12 | 2001-10-25 | Power Line Networks | Transmission system and method for power line communication |
| US8184014B2 (en) | 2008-06-27 | 2012-05-22 | Schlumberger Technology Corporation | Driver to transmit signals over a transmission line in a well |
| WO2015176381A1 (en) * | 2014-05-21 | 2015-11-26 | 瑞斯康微电子（深圳）有限公司 | Power line carrier power amplification circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| AU1425597A (en) | 1997-07-14 |
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