Patent EP0510756A2 successfully refreshed from Google Patents.
EP0510756A2
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Sample tuning recovery for receivers using Viterbi processing
Assignee: Koninklijke Philips NV
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Filing: 1992-04-15
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Granted: —
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Expires: 2012-04-15
Abstract
Abstract Data receiver in which a received signal is sampled and converted to a digital signal by an analog-to-digital converter (1), the signal samples being detected by means of a Viterbi detector (3). In order to have the sampling effected at the correct instants, these sampling instants are derived from the received symbol values and an error signal which is a metric for a difference between an expected and a recent signal sample. This is effected by means of a multiplier 4, a low-pass filter 5 and a control signal for a controllable clock oscillator (6). For utilizing the energy in a precursor of the received signal, an error signal e(k-1) is used which is obtained at a later instant than the instant at which a provisional decision about the relevant data symbol a/< ANd >(k-2) is made. <IMAGE>
Inventors
- 👤 Johannes Wilhelmus Maria Bergmans
- 👤 Ho Wai Wong
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 00:48
CPC Classifications
H; H04; H04L; H04L13/00; H04L7/00; H04L7/0054; H04L7/0062; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03178; H04L25/03248
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
237 words
Data receiver comprising deriving means for deriving a detection signal from an input signal, the output of the deriving means being coupled to the input of detection means which determine a most probable sequence of data symbols on the basis of the detection signal, the symbols occurring in the detection signal with a symbol interval T, by recursively updating candidate sequences (survivors) with associated path metrics derived from branch metrics, the branch metrics being an even function of a difference value e k present at a sampling instant kT of the detection signal and of the detection signal expected for the relevant candidate survivor, while k is an integer, characterized in that the receiver comprises timing means for delaying the sampling instants if - the sign of the difference value e k-n at a sampling instant (k-n)T, where n is a fixed positive number and where the difference value is associated to the most probable candidate survivor at the sampling instant kT, and the sign of an estimate f (k-n-m)T ( a ˆ k-n-m ) of the contribution of a symbol a ˆ k-n-m (m = 1,2,3,...) estimated at a sampling instant (k-n-m)T to the detection signal at an instant (k-n-m)T are equal, the symbol a ˆ k-n-m being taken from the candidate survivor which is the most probable at the sampling instant kT; and for advancing the sampling instants - if the two signs are different.
Claim 2
Dependent Claim
223 words
Receiver as claimed in Claim 1, characterized in that m is equal to 1, in that in the detection means the input of the detection means is coupled to a first Viterbi detector via first correction means, in that in the detection means the input of the detection means is coupled to a second Viterbi detector via second correction means, the first correction means subtracting a first correction signal from the input signal of the first correction means and the second correction means subtracting a second correction signal from the input signal of the second correction means, the first and second correction signals being equal to: whilst for the first correction signal, â k-2i-1 is taken from the candidate survivor in the second Viterbi detector most probable at an even sampling instant kT, and for the second correction signal, â k-2i-1 is taken from the candidate survivor in the second Viterbi detector most probable at an odd sampling instant kT, where g t (â k-2i-1 ) at instants (k+p)T with p being an integer greater than or equal to 0 equals f t ( a ˆ k-2i+1 ) ; where N is the length in numbers of symbol intervals of the estimate response f t , where N' equals (N-3)/2 if N is odd and where N' equals (N-2)/2 if N is even.
Claim 3
Dependent Claim
85 words
Receiver as claimed in one of the Claims 1 or 2, characterized in that N' is equal to 1, in that the number of possible symbol values is equal to 2 and in that a path metric difference is updated that is a measure for the difference between a first sum of even function values of the consecutive branch metrics associated to a first candidate survivor and a second sum of even function values of the consecutive branch metrics associated to a second candidate survivor.
Claim 4
Dependent Claim
89 words
Receiver as claimed in one of the preceding Claims, characterized in that the receiver comprises adapting means for adapting f t to the recent response of the medium to a data symbol on the basis of the branch metrics e and the estimated data symbols â, characterized in that the adapting means adapt f t at an instant kT on the basis of the branch metric e k-n present at an instant (k-n)T , which branch metric is associated to the candidate survivor most probable at the instant kT.
References Cited (Backward Citations)
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