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EP0040801A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Automatic equalizer

Assignee: Toshiba Corp
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Filing: 1981-05-20
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Granted: —
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Expires: 2001-05-20
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Abstract

Abstract An automatic equalizer comprises a transversal filter (2) connected to receive an input signal such as a television signal in which a predetermined periodic reference signal is present and having variable tap gains, and a correlator (8) for forming the correlation between the input and output signals of the transversal filter and correcting the tap gains of the transversal filter to cancel out distortion components such as ghost component contained in the input signal. For the purpose of preventing the slow convergence and fluctuation of tap gains of the transversal filter (2) due to nonperiodic noise components contained in the input signal, a circuit (30) is further provided to integrate a predetermined portion of the waveform of the reference signal contained in the input signal. An output signal of the waveform integrator circuit (30) is correlated with the output signal of the transversal filter (2) by the correlator (8).

Inventors

  • 👤 Shunichi Onishi
  • 👤 Masaharu Obara
  • 👤 Masaru Sakurai
  • 👤 Junzo Murakami
  • 👤 Shinichi Makino

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 19:12
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038; H04N; H04N5/00; H04N5/14; H04N5/21; H04N5/211

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 132 words
An automatic equalizer comprising a transversal filter (2) connected to receive an input signal in which a predetermined reference signal is periodically contained and having variable tap gains, a correlator (8) for obtaining the correlation between the input signal and the output signal of said transversal filter, and means (9, 10, 11, 12) responsive to the output of said correlator to correct the tap gains of said transversal filter, characterized in that a waveform integrator circuit (30) is provided to integrate the waveform of the reference signal contained in the input signal every time when the reference signal appears and that said correlator (8) responds to the outputs of said waveform integrator circuit and transversal filter to obtain the correlation between the input signal and the output signal of said transversal filter.
Claim 2
Dependent Claim 132 words
An automatic equalizer comprising a transversal filter (2) connected to receive an input signal in which a predetermined reference signal is periodically contained and having variable tap gains, a correlator (8) for obtaining the correlation between the input signal and the output signal of said transversal filter, and means (9, 10, 11, 12) responsive to the output of said correlator to correct the tap gains of said transversal filter, characterized in that a waveform integrator circuit (30) is provided to integrate the waveform of the reference signal contained in the input signal every time when the reference signal appears and that said correlator (8) responds to the outputs of said waveform integrator circuit and transversal filter to obtain the correlation between the input signal and the output signal of said transversal filter.
Claim 3
Dependent Claim 93 words
An automatic equalizer according to claim 1 wherein said waveform integrator circuit (30) includes a waveform memory (31) for digitally storing in the predetermined interval the waveform of a predetermined portion of the reference signal contained in the input signal, a digital-to-analog converter (32) connected to the output of said waveform memory (31), a level comparator '(33) connected to receive the input signal and the output signal of said digital-to-analog converter, and a means (35) responsive to the output of said level comparator to correct the digital values stored in said waveform memory.

References Cited (Backward Citations)

GB1424701A Cited
US4127874A Cited

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