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EP0330282A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Receiver of a system for transmitting data symbols at a given baud-rate

Assignee: AT&T Network Systems International BV
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Filing: 1989-02-20
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Granted: —
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Expires: 2009-02-20
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Abstract

Abstract A receiver of a system for transmitting data symbols at a given baud-rate comprises a symbol detector (7) operating at the baud-­rate 1/T and means (6) for optimally conditioning received data symbols for this symbol detection. From the received conditioned data signal [s(k)] a phase error signal [e(k-1).ĉ(k)] is derived that is representative of a phase difference between a locally generated baud-­rate clock signal and a baud-rate clock signal inherent to the received data symbols, and the receiver comprises means (11, 12) for the reduction of this phase difference step-by-step in response to the phase error signal [e(k - 1).ĉ(k)]. This receiver further includes an accumulator (44) for determining the mean value [u(k)] of the phase error signal over a predetermined number (M) of symbol intervals and a detector (45) for establishing whether this mean value [u(k)] is situated in a zone whose boundaries [±V r (k)/N] are determined by a given fraction (1/N, N > 1) of the level [V r (k)] of the conditioned signal [s(k)]. If the mean value [u(k)] of the phase error signal is situated in this zone, the process of shifting the phase of the local clock signal step-by-step is stopped.

Inventors

  • 👤 Simon Johannes Maria Tol
  • 👤 Kornelis Jan Wouda

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-10 01:25
CPC Classifications
H; H04; H04L; H04L7/00; H04L7/0054; H04L7/0062

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 185 words
A receiver of a system for transmitting data symbols at a given baud-rate 1/T, this receiver comprising a symbol detector operating at the baud-rate 1/T; means for optimally conditioning the received data sybols for symbol detection; means for deriving from the conditioned signal an error signal which is representative of a phase difference between a baud-rate clock signal associated with the received data symbols and a locally generated baud-rate clock signal for the symbol detector; and phase control means for reducing this phase difference in a step-by-step fashion in response to the error signal, characterized in that the receiver comprises means for establishing whether the mean error signal value, over a predetermined number of symbol intervals, is situated in a zone whose boundaries are determined by a first given fraction of the level of the conditioned signal at the symbol detection instant, and means for blocking the phase control means in the said mean error signal value is situated in the said zone, and also for unblocking the phase control means if the mean error signal value in the blocked state meets a predetermined criterion.
Claim 2
Dependent Claim 185 words
A receiver of a system for transmitting data symbols at a given baud-rate 1/T, this receiver comprising a symbol detector operating at the baud-rate 1/T; means for optimally conditioning the received data sybols for symbol detection; means for deriving from the conditioned signal an error signal which is representative of a phase difference between a baud-rate clock signal associated with the received data symbols and a locally generated baud-rate clock signal for the symbol detector; and phase control means for reducing this phase difference in a step-by-step fashion in response to the error signal, characterized in that the receiver comprises means for establishing whether the mean error signal value, over a predetermined number of symbol intervals, is situated in a zone whose boundaries are determined by a first given fraction of the level of the conditioned signal at the symbol detection instant, and means for blocking the phase control means in the said mean error signal value is situated in the said zone, and also for unblocking the phase control means if the mean error signal value in the blocked state meets a predetermined criterion.
Claim 3
Dependent Claim 32 words
A receiver as claimed in Claim 1, characterized in that means are provided for averaging the error signal over a larger number of symbol intervals when the phase control means are blocked.
Claim 4
Dependent Claim 67 words
A receiver as claimed in Claim 1 or 2, characterized in that means are provided for determining, when the phase control means are blocked, the boundaries of the said zone in accordance with a second given fraction of the level of the conditioned signal at the symbol detection instant, this second fraction exceeding said first fraction, whereby enlarged zone for permissible mean error signal values is attained.
Claim 5
Dependent Claim 35 words
A receiver as claimed in one of the Claims 1-3, characterized in that counting means are provided for counting how many times the average error signal is situated in said zone or said enlarged zone.
Claim 6
Dependent Claim 31 words
A receiver as claimed in Claim 4, characterized in that the counting means are reset as soon as the mean error signal is for once not situated in said enlarged zone.
Claim 7
Dependent Claim 35 words
A receiver as claimed in Claim 5, characterized in that the boundaries of the said zone are transferred to the boundaries of said enlarged zone when the counting means have reached a predetermined counting value.
Claim 8
Dependent Claim 26 words
A receiver as claimed in Claim 1, characterized in that the mean error signal meets the predetermined criterion when this signal is situated outside said zone.
Claim 9
Dependent Claim 27 words
A receiver as claimed in Claim 3, characterized in that the mean error signal meets the predetermined criterion when this signal is situated outside the enlarged zone.
Claim 10
Dependent Claim 25 words
A receiver as claimed in one of the Claims 1-3, characterized in that means are provided for limiting the peak values of the error signal.

References Cited (Backward Citations)

US3777272A Cited
US4494242A Cited

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