EP0428129B1
Expired / Lapsed
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Method and apparatus of decision feedback equalization for multipath digital communication
Assignee: Toshiba Corp
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Filing: 1990-11-13
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Granted: 1996-01-10
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Expires: 2010-11-13
Abstract
No abstract record available.
Inventors
- 👤 Mutsuma Serizawa
- 👤 Koji Ogura
- 👤 Katsumi Sakakibara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 18:35
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03057
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
134 words
An apparatus for decision feedback equalization of a digital transmission signal read in a normal time direction or a reversed time direction, comprising: - a number of feedforward taps for providing a forward part (37, 47) ; - a number of feedback taps for providing a feedback part (36, 46); - an adder (38, 48) for adding the forward part and the feedback part; and - a decision device (41, 51) for reconstructing the digital transmission signal according to an output of the adder characterized by - means (33, 34, 35) for controlling the number of feedforward taps and the number of feedback taps according to whether the transmission signal is to be read in normal time direction or in reversed time direction, wherein the numbers of feedforward taps and feedback taps are variable.
Claim 2
Dependent Claim
75 words
The apparatus of claim 1, wherein by said means for controlling the number of feedforward taps and the number of feedback taps, the number of feedback taps is made greater than the number of feedforward taps when the transmission signal is to be read in normal time direction, and the number of feedforward taps is made greater than the number of feedback taps when the transmission signal is to be read in reversed time direction.
Claim 3
Dependent Claim
89 words
The apparatus of claim 1, wherein by said means for controlling the number of feedforward taps and the number of feedback taps, the number of feedforward taps is made greater for a case of reading the tranmission signal in reversed time direction than for a case of reading the transmission signal in normal time direction, and the number of feedback taps is made greater for a case of reading the transmission signal in normal time direction than for a case of reading the transmission signal in reversed time direction.
Claim 4
Independent Claim
27 words
The apparatus according to any one of claims 1 to 3, wherein the total number of the feedforward taps and the feedback taps is a constant number.
Claim 5
Independent Claim
91 words
The apparatus according to any one of claims 1 to 4 wherein the number of the feedforward taps is varied by switching between a first set of the feedforward taps and a second set of the feedforward taps which has a greater number of the feedforward taps than the first set, and the number of the feedback taps is varied by switching between a first set of the feedback taps and a second set of the feedback taps which has a greater number of the feedback taps than the first set.
Claim 6
Independent Claim
74 words
The apparatus according to any one of claims 1 to 4, wherein the number of the feedforward taps is made variable by making each feedforward tap freely disconnectable, and the number of the feedback taps is made variable by making each feedback tap freely disconnectable, and wherein said means for controlling the number of the feedforward taps and feedback taps change the number of disconnected feedforward taps and the number of disconnected feedback taps.
Claim 7
Independent Claim
46 words
The apparatus according to any one of claims 1 to 6, further comprising means for adjusting tap coefficients of the feedforward taps and the feedback taps according to a difference between the output of the adder and the digital transmission signal reconstructed by the decision device.
Claim 8
Independent Claim
119 words
A method of decision feedback equalization of a digital transmission signal read in a normal time direction or a reversed time direction, comprising the steps of: - supplying the digital transmission signal to a feedforward part provided by feedforward taps; - supplying the digital transmission signal to a feedback part provided by feedback taps; - adding the forward part and the feedback part; and - reconstructing the digital transmission signal according to the result of the adding step; characterized by - controlling the number of feedforward taps and feedback taps according to whether the transmission signal is to be read in normal time direction or reversed time direction, wherein the numbers of feedforward taps and feedback taps are variable.
Claim 9
Dependent Claim
78 words
The method of claim 8, wherein at the controlling step, the number of feedforward taps and the number of feedback taps are controlled such that the number of feedback taps is made greater than a number of feedforward taps when the transmission signal is to be read in normal time direction, and the number of feedforward taps is made greater than a number of feedback taps when the transmission signal is to be read in reversed time direction.
Claim 10
Dependent Claim
92 words
The method of claim 8, wherein at the controlling step, the number of feedforward taps and the number of feedback taps are controlled such that the number of feedforward taps is made greater for a case of reading the transmission signal in reversed time direction than for a case of reading the transmission signal in normal time direction, and the number of feedback taps is made greater for a case of reading the transmission signal in normal time direction than for a case of reading the transmission signal in reversed time direction.
Claim 11
Independent Claim
27 words
The method according to any one of claims 8 to 10, wherein the total number of the feedforward taps and the feedback taps is a constant number.
Claim 12
Independent Claim
91 words
The method according to any one of claims 8 to 11, wherein the number of the feedforward taps is varied by switching between a first set of the feedforward taps and a second set of the feedforward taps which has a greater number of the feedforward taps than the first set, and the number of the feedback taps is varied by switching between a first set of the feedback taps and a second set of the feedback taps which has a greater number of the feedback taps than the first set.
Claim 13
Independent Claim
83 words
The method according to any one of claims 8 to 11, wherein the number of the feedforward taps is made variable by making each feedforward tap freely disconnectable, and the number of the feedback taps is made variable by making each feedback tap freely disconnectable, and wherein at the controlling step the number of the feedforward taps is controlled by changing a number of disconnected feedforward taps and the number of feedback taps is controlled by changing a number of disconnected feedback taps.
Claim 14
Independent Claim
48 words
The method according to any one of claims 8 to 13, further comprising the step of adjusting tap coefficients of the feedforward taps and the feedback taps according to a difference between the result of the adding step and the digital transmission signal reconstructed at the reconstructing step.
References Cited (Backward Citations)
No citation records indexed.
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