NINETY-DEGREE PHASE SHIFTER CIRCUIT AND CORRESPONDING NINETY-DEGREE PHASE-SHIFTING METHOD
First Claim
1. A phase-shifter circuit, comprising:
- a continuous-time all-pass filter stage configured to receive a sinusoidal input signal and generate an output signal phase-shifted by 90°
at a phase-shift frequency that is a function of a RC time constant of said all-pass filter stage; and
a calibration stage coupled to the all-pass filter stage and configured to generate a calibration signal for said all-pass filter stage such that the phase-shift frequency is substantially equal to an input frequency of the sinusoidal input signal.
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Abstract
A phase shifter, which carries out a ninety-degree phase shift of a sinusoidal input signal having an input frequency, at the same input frequency, envisages: a continuous-time all-pass filter stage, which receives the sinusoidal input signal and generates an output signal phase-shifted by 90° at a phase-shift frequency that is a function of a RC time constant of the all-pass filter stage; and a calibration stage, which is coupled to the all-pass filter stage and generates a calibration signal for the all-pass filter stage, such that the phase-shift frequency is equal to the input frequency of the sinusoidal input signal, irrespective of variations of the value of the input frequency and/or of the RC time constant with respect to a nominal value.
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Citations
18 Claims
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1. A phase-shifter circuit, comprising:
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a continuous-time all-pass filter stage configured to receive a sinusoidal input signal and generate an output signal phase-shifted by 90°
at a phase-shift frequency that is a function of a RC time constant of said all-pass filter stage; anda calibration stage coupled to the all-pass filter stage and configured to generate a calibration signal for said all-pass filter stage such that the phase-shift frequency is substantially equal to an input frequency of the sinusoidal input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A MEMS gyroscope, comprising:
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a micromechanical sensing structure; and a reading-interface circuit coupled to the micromechanical sensing structure, said reading-interface circuit including a phase-shifter circuit, the phase-shifter circuit including; a continuous-time all-pass filter stage configured to receive a sinusoidal input signal and generate an output signal phase-shifted by 90°
at a phase-shift frequency that is a function of a RC time constant of the all-pass filter stage; anda calibration stage coupled to the all-pass filter stage and configured to generate a calibration signal for the all-pass filter stage such that the phase-shift frequency is substantially equal to an input frequency of the sinusoidal input signal. - View Dependent Claims (11, 12, 13)
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14. A phase-shifting method, comprising:
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receiving, by a continuous-time all-pass filter stage, a sinusoidal input signal; generating, by the continuous-time all-pass filter stage, an output signal, the output signal being phase-shifted with respect to the input signal by 90°
at a phase-shift frequency that is a function of a RC time constant of said all-pass filter stage; andgenerating a calibration signal for said all-pass filter stage, such that the phase-shift frequency is equal to an input frequency of the sinusoidal input signal, irrespective of variations of the value of said input frequency and/or of said RC time constant with respect to a nominal value. - View Dependent Claims (15, 16, 17, 18)
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Specification