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EP0204308A2
Expired / Lapsed
EP
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Modem communication system having training means and method for training same
Assignee: Fujitsu Ltd
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Filing: 1986-06-03
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Granted: —
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Expires: 2006-06-03
Abstract
Abstract A multipoint type MODEM communication system having a training device for adapting receiving parameters in a receiving MODEM (101) to a characteristic of a telephone line (300) connected to a sending MODEM in response to a training signal sent from the sending MODEM (201, 211, 222) prior to the reception of data. The training signal includes at least two impulses, a time between them defining the characteristic of the telephone line which should be adjusted in the receiving MODEM. The training signal may be superimposed on a tone and a timing signal, which are used for gain control and pull-in synchronization, and the impulses used for equalization and carrier-phase-control. The training signal also may include the tone, the timing signal, and the impulses in series. Additional guard impulses may be added prior to and/or after the impulses. A scramble signal also may be added after the impulses. In addition, a method for training the receiving MODEM is disclosed.
Inventors
- 👤 Takashi Kaku
- 👤 Yasuhiro Arai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 08:41
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/38; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03114; H04L25/03133; H04L7/00; H04L7/02; H04L7/027; H04L2025/03777; H04L2025/03783; H04L7/04; H04L7/041; H04L7/046
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
279 words
A modulator and demodulator (MODEM) communication system comprising: telephone line means having a telephone line - (300); a control station including a MODEM (101) and operatively connected to said telephone line through said MODEM (101); and, one on more local stations each including antoher MODEM (201, 211, 221), and operatively connected to said telephone line through said another MODEM (201, 211, 221) and to said central station through said another MODEM (201, 211, 221), said telephone line and said MODEM (101); said MODEM (101) carrying out a polling of said another MODEMs (201, 211, 221), the corresponding another MODEM (201, 211, 221) undergoing said polling sending a signal having a training signal and data to said MODEM (101), said training signal sent from said another MODEM (201, 211, 221) containing a carrier, a timing signal and at least two impulses, a time between said two impulses defining a characteristic of said telephone line between said corresponding another MODEM - (201, 211, 221) and said MODEM (101), said MODEM (101) including first means (1, 2, 3, 4, 7) for receiving and demodulating said signal having said training signal, second means (11, 8, 4, 6, 18) for detecting said carrier and said timing signal and performing a gain control and a pulling-in synchronization to said corresponding another MODEM (201, 211, 221), and third means (12, 13, 14, 15, 17, 16, 18) for recoverying said impulses and for performing an equalization and a carrier phase control in response to said recovered im- palse, said data contained in said signal sent from said corresponding another MODEM (201, 211, 221) being adjusted in response to said gain control, synchronization equalization and carrier phase control.
Claim 2
Dependent Claim
279 words
A modulator and demodulator (MODEM) communication system comprising: telephone line means having a telephone line - (300); a control station including a MODEM (101) and operatively connected to said telephone line through said MODEM (101); and, one on more local stations each including antoher MODEM (201, 211, 221), and operatively connected to said telephone line through said another MODEM (201, 211, 221) and to said central station through said another MODEM (201, 211, 221), said telephone line and said MODEM (101); said MODEM (101) carrying out a polling of said another MODEMs (201, 211, 221), the corresponding another MODEM (201, 211, 221) undergoing said polling sending a signal having a training signal and data to said MODEM (101), said training signal sent from said another MODEM (201, 211, 221) containing a carrier, a timing signal and at least two impulses, a time between said two impulses defining a characteristic of said telephone line between said corresponding another MODEM - (201, 211, 221) and said MODEM (101), said MODEM (101) including first means (1, 2, 3, 4, 7) for receiving and demodulating said signal having said training signal, second means (11, 8, 4, 6, 18) for detecting said carrier and said timing signal and performing a gain control and a pulling-in synchronization to said corresponding another MODEM (201, 211, 221), and third means (12, 13, 14, 15, 17, 16, 18) for recoverying said impulses and for performing an equalization and a carrier phase control in response to said recovered im- palse, said data contained in said signal sent from said corresponding another MODEM (201, 211, 221) being adjusted in response to said gain control, synchronization equalization and carrier phase control.
Claim 3
Dependent Claim
33 words
A MODEM communication system according to claim 1, wherein said training signal sent from said another MODEM (201, 211, 221) contains said carrier, said timing signal, and said impulses superimposed upon each other.
Claim 4
Dependent Claim
25 words
A MODEM communication system according to claim 2, wherein said training signal further contains a forward impulse prior to said impulses, for guarding said impulses.
Claim 5
Dependent Claim
27 words
A MODEM communication system according to claim 2 or 3, wherein said training signal further contains a scramble signal having a random pattern data after said impulses.
Claim 6
Dependent Claim
30 words
A MODEM communication system accordinq to any of claims 2, S or 4, wherein said training signal further contains a reverse impulse between said last impulse and said scramble signal.
Claim 7
Dependent Claim
93 words
A MODEM communication system according to claim 2, wherein said second means of said MODEM (101) comprises means (11) for detecting said carrier, means (8) for controlling a gain, means (4), for extracting said timing signal, and means (6) for rotating a phase of said extracted timing signal, and said third means of said MODEM (101) comprises means (12) for recovering said received impulses, means (13, 14) for equalizing a characteristic to said another MODEM (201, 211, 221), and means (15) for controlling a carrier phase to said another MODEM (201, 211, 221).
Claim 8
Dependent Claim
31 words
A MODEM communication system according to claim 1, wherein said training signal sent from said another MODEM (201, 211, 221) contains said carrier, said timing signal and said impulses in series.
Claim 9
Dependent Claim
29 words
A MODEM communication system according to claim 7, wherein said training signal further contains a forward impulse between said timing signal and said first impulse, for guarding said impulses.
Claim 10
Dependent Claim
28 words
A MODEM communication system according to claim 7 or 8, wherein said training signal also further contains a scramble signal having a random pattern data after said impulses.
Claim 11
Dependent Claim
30 words
A MODEM communication system according to any of claims 7, 8 or 9, wherein said training signal further contains a reverse impulse between said east impulse and said scramble signal.
Claim 12
Dependent Claim
85 words
A MODEM communication system according to claim 7, wherein said sacond means of said MODEM (101) comprises means (11) for detecting said carrier, means (8) for controlling a gain, and means (4') for extracting said timing signal and pulling-in the synchronization, and said third means of said MODEM (101) comprises means (12) for recovering said received impulses, means (13, 14) for equalizing a characteristic to said another MODEM (201, 211, 221), and means (15) for controlling a carrier phase to said another MODEM - (201.211,221).
Claim 13
Dependent Claim
22 words
A MODEM communication system according to claim 1, wherein said signal sent from said another MODEM (201, 211, 221) is guadrature- amplitude-modified.
Claim 14
Independent Claim
196 words
A method for training a MODEM in a MODEM communication system including telephone line means having a telephone line (300), a central station including a MODEM (101) operatively connected to said telephone line and one or more local stations each including another MODEM (201, 211, 221) operatively connected to said telephone line, comprising the steps of: polling from said MODEM (101) in said central station to said another MODEMs (201, 211, 221) in said local stations through said telephone line; sending a signal having a training signal, containing a carrier, a timing signal and at least two impulses and data, from said polled MODEM (201, 211, 221) to said MODEM (101) through said telephone line, a time between said impulses defining a characteric of said telephone line between said polled MODEM (201, 211, 221) and said MODEM - (101); receiving and demodulating said training signal in said MODEM (101); detecting said carrier and said timing signal in said MODEM (101) to adjust a gain and to pull-in synchronization to said polled MODEM (201, 211, 221 and recoverying said impulses and performing an equalization and carrier phase control in response to said time of said recovered impulses.
Claim 15
Independent Claim
196 words
A method for training a MODEM in a MODEM communication system including telephone line means having a telephone line (300), a central station including a MODEM (101) operatively connected to said telephone line and one or more local stations each including another MODEM (201, 211, 221) operatively connected to said telephone line, comprising the steps of: polling from said MODEM (101) in said central station to said another MODEMs (201, 211, 221) in said local stations through said telephone line; sending a signal having a training signal, containing a carrier, a timing signal and at least two impulses and data, from said polled MODEM (201, 211, 221) to said MODEM (101) through said telephone line, a time between said impulses defining a characteric of said telephone line between said polled MODEM (201, 211, 221) and said MODEM - (101); receiving and demodulating said training signal in said MODEM (101); detecting said carrier and said timing signal in said MODEM (101) to adjust a gain and to pull-in synchronization to said polled MODEM (201, 211, 221 and recoverying said impulses and performing an equalization and carrier phase control in response to said time of said recovered impulses.
Claim 16
Dependent Claim
36 words
A method for training a MODEM according to claim 13, wherein said training training signal sent from said polled MODEM (201, 211, 221) contains said carrier, said timing signal and said impulses superimposed on each other.
Claim 17
Dependent Claim
27 words
A method for training a MODEM according to claim 14, wherein said training signal further contains a forward impulse prior to said impulses, for guarding said impulses.
Claim 18
Dependent Claim
29 words
A method for training a MODEM according to claim 14 or 15, wherein said training signal further contains a scramble signal having a random pattern data after said impulses.
Claim 19
Independent Claim
31 words
A method for training a MODEM according to any of claims 14, 15 or 16, wherein said training signal further contains a reverse impulse between said impulses and said scramble signal.
Claim 20
Dependent Claim
26 words
A method for training a MODEM according to claim 16 or 17, further comprising discriminating said scramble signal and adjusting said equalization and carrier phase control.
Claim 21
Dependent Claim
33 words
A method for training a MODEM according to claim 13, wherein said training signal sent from said polled MODEM (201, 211, 221) contains said carrier, said timing signal and said impulses in series.
Claim 22
Dependent Claim
31 words
A method for training a MODEM according to claim 19, wherein said training signal further contains a forward impulse between said timing signal and said first impulse, for guarding said impulses.
Claim 23
Dependent Claim
29 words
A method for training a MODEM according to claim 19 or 20, wherein said training signal further contains a scramble signal having a random pattern data after said impulses.
Claim 24
Independent Claim
32 words
A method for training a MODEM according to any of claims 19, 20 or 21, wherein said training signal further contains a reverse impulse between said last impulse and said scramble signal.
Claim 25
Independent Claim
28 words
A method for training a MODEM according to any of claims 19 to 22, further comprising discriminating said scramble signal and adjusting said equalization and carrier phase control.
Claim 26
Dependent Claim
22 words
A MODEM communication system according to claim 13, wherein said signal sent from said polled MODEM (201, 211, 221) is guadrature- amplitude-modified.
References Cited (Backward Citations)
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