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公开(公告)号：FR2835667A1
公开(公告)日：2003-08-08
申请号：FR0201516
申请日：2002-02-07
Applicant: ST MICROELECTRONICS SA
Inventor： RAVATIN JEAN , MOURET MICHEL , VAN ZANTEN FRANCOIS
Abstract: The filter is set up by firstly operating in oscillator mode, during which time the oscillator frequency is measured. The characteristics of the filter are adjusted in order to match the required cut-off frequency for the filter, as closely as possible, within a determined degree of tolerance. The filter control procedure includes a phase in which the filtering circuit (FF10) operates as an oscillator, and the frequency of operation of the oscillator is determined. The characteristics of the device are then corrected, taking account of the measured frequency of oscillation and a predetermined relationship between the frequency of oscillation and the theoretical cut-off frequency of the filter. This gives the circuit a cut-off frequency which is equal to the frequency of oscillation, within a close tolerance. After this adjustment phase, the filter moves into a working phase, in which the filter carries out its filtering function. When the filter has an order greater than three, the filter operates in oscillator mode by re-looping to itself with phase inversion. When the filter operates with order less than three, an additional series filter is provided to form the oscillator loop.
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Patent Agency Ranking
公开(公告)号：FR2821500A1
公开(公告)日：2002-08-30
申请号：FR0102587
申请日：2001-02-26
Applicant: ST MICROELECTRONICS SA
Inventor： GIRY CASSAN FLORENCE , RAVATIN JEAN
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公开(公告)号：FR2835667B1
公开(公告)日：2006-08-04
申请号：FR0201516
申请日：2002-02-07
Applicant: ST MICROELECTRONICS SA
Inventor： RAVATIN JEAN , MOURET MICHEL , VAN ZANTEN FRANCOIS
Abstract: The filter is set up by firstly operating in oscillator mode, during which time the oscillator frequency is measured. The characteristics of the filter are adjusted in order to match the required cut-off frequency for the filter, as closely as possible, within a determined degree of tolerance. The filter control procedure includes a phase in which the filtering circuit (FF10) operates as an oscillator, and the frequency of operation of the oscillator is determined. The characteristics of the device are then corrected, taking account of the measured frequency of oscillation and a predetermined relationship between the frequency of oscillation and the theoretical cut-off frequency of the filter. This gives the circuit a cut-off frequency which is equal to the frequency of oscillation, within a close tolerance. After this adjustment phase, the filter moves into a working phase, in which the filter carries out its filtering function. When the filter has an order greater than three, the filter operates in oscillator mode by re-looping to itself with phase inversion. When the filter operates with order less than three, an additional series filter is provided to form the oscillator loop.
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公开(公告)号：FR2850499A1
公开(公告)日：2004-07-30
申请号：FR0300933
申请日：2003-01-28
Applicant: ST MICROELECTRONICS SA
Inventor： RAVATIN JEAN , VAN ZANTEN FRANCOIS
Abstract: The circuit for correcting the offset of a chain (2) for amplification and low-pass filtering having a predetermined gain (G) and cut-off frequency (Fc) depending on the value of at least one capacitor, comprises a digital-analog converter (18) for the return of a correction signal (delta) dependent on the value of a programmable digital word (COM), a digital automaton (14) for finding and storing one of two consecutive values of the digital word between which the output signal changes sign so that the input signal is annulled during an adjustment phase, and tuning elements (22,24) for reducing the value of at least one capacitor with respect to its normal functioning value. The circuit with a determined cut-off frequency (Fc) dependent on several capacitors comprises means for reducing the value of each capacitance during the tuning phase. The means for reducing the value of at least one capacitance consist of means for switching at least one capacitor with another of lower capacitance, or at least one capacitor is formed of a low-value capacitance connected in parallel with a set of small capacitors each in series with a programmable switch. The method (claimed) for correcting the offset of a chain for amplification and low-pass filtering, comprises the steps of annulling the input signal, returning a correction signal dependent on the value of a digital word and modifying the value until the output signal changes sign, and storing the value of the digital word.
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公开(公告)号：FR2850499B1
公开(公告)日：2005-10-21
申请号：FR0300933
申请日：2003-01-28
Applicant: ST MICROELECTRONICS SA
Inventor： RAVATIN JEAN , VAN ZANTEN FRANCOIS
Abstract: The circuit for correcting the offset of a chain (2) for amplification and low-pass filtering having a predetermined gain (G) and cut-off frequency (Fc) depending on the value of at least one capacitor, comprises a digital-analog converter (18) for the return of a correction signal (delta) dependent on the value of a programmable digital word (COM), a digital automaton (14) for finding and storing one of two consecutive values of the digital word between which the output signal changes sign so that the input signal is annulled during an adjustment phase, and tuning elements (22,24) for reducing the value of at least one capacitor with respect to its normal functioning value. The circuit with a determined cut-off frequency (Fc) dependent on several capacitors comprises means for reducing the value of each capacitance during the tuning phase. The means for reducing the value of at least one capacitance consist of means for switching at least one capacitor with another of lower capacitance, or at least one capacitor is formed of a low-value capacitance connected in parallel with a set of small capacitors each in series with a programmable switch. The method (claimed) for correcting the offset of a chain for amplification and low-pass filtering, comprises the steps of annulling the input signal, returning a correction signal dependent on the value of a digital word and modifying the value until the output signal changes sign, and storing the value of the digital word.
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公开(公告)号：FR2821500B1
公开(公告)日：2005-05-13
申请号：FR0102587
申请日：2001-02-26
Applicant: ST MICROELECTRONICS SA
Inventor： GIRY CASSAN FLORENCE , RAVATIN JEAN
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