Fully differential demodulator with variable gain, and method for demodulating a signal

A method for demodulation of a signal, comprising:

• receiving, by an amplifier stage, an amplitude-modulated input signal, defined by a carrier signal at a carrier frequency and a modulating signal;
• and
• generating, by a control stage, timing signals according to the carrier frequency of the carrier signal;
• amplifying, by the amplifier stage, the input signal with a gain that is varied according to the carrier frequency of the carrier signal;
• receiving, by the control stage, an output signal from the amplifier stage;
• and
• varying the output signal according to the carrier frequency of the carrier signal.

A circuit system, comprising:

• a microelectromechanical device;
• a variable gain amplifier stage adapted to receive coupled to the microelectromechanical device, the variable gain amplifier stage including circuitry which, in operation, receives an amplitude modulated signal from the microelectromechanical device, and to generate generates an output signal having a gain;
• and
• a gain control stage coupled to the variable gain amplifier stage, the gain control stage adapted to receive as input, in operation, receives a carrier signal of the amplitude modulated signal from the microelectromechanical device, the control stage including:
• a timing signal generator which, in operation, generates timing signals based on a frequency of the carrier signal, and provides the timing signals to the variable gain amplifier stage, the variable gain amplifier stage, in operation, varies the gain of the output signal based on the timing signals;
• and to generate a gain control signal to control the gain of the variable gain amplifier stage in response to a frequency of a sign-inverting circuit which, in operation, receives the output signal, and inverts the output signal at each half-period of the carrier signal and to bring the amplitude modulated signal into a baseband in the output signal;
• and
• a zero circuit which, in operation, couples and uncouples the sign-inverting circuit from the variable gain amplifier stage at each half-period of the carrier signal.

A gyroscopic An apparatus, comprising:

• a gyroscope device generating having a first moveable mass and a second movable mass, the device, in operation, generates a modulated signal, the gyroscope device comprising two microstructure movable masses and a read interface, the modulated signal comprising a discrete-time analog voltage given by a product of a modulating signal and a carrier signal having a carrier frequency, the carrier frequency comprising a mechanical resonance frequency of the two movable masses and an amplitude modulation that is proportional to an angular velocity of the gyroscope device;
• and
• a demodulator of the discrete-time analog type, the demodulator comprising that includes:
• a variable gain an amplifier stage adapted to receive an amplitude having a gain, the amplifier stage including circuitry which, in operation, receives the modulated signal and to generate generates an output signal having a the gain;
• and
• a gain control stage coupled to the variable gain amplifier stage, the gain control stage adapted to receive as input, in operation, receives a carrier signal of the amplitude modulated signal from the device, the control stage including:
• and to generate a gain a signal generator which, in operation, generates a control signal to control the gain of the variable gain amplifier stage in response to based on a frequency of the carrier signal and to bring the amplitude modulated signal into a baseband in the output signal, and provides the control signal to the amplifier stage, the amplifier stage, in operation, controls the gain based on the control signal;
• and
• a sign-inverting circuit which, in operation receives the output signal and inverts the output signal at each half-period of the carrier signal.

A device, comprising:

• means for receiving a modulated input signal that includes a carrier signal modulated by a modulating input signal;
• means for generating timing signals according to a frequency of the carrier signal;
• means for amplifying the modulated input signal with a gain using the timing signals;
• and
• means for receiving the amplified modulated input signal, and inverting the amplified modulated signal according to the frequency of the carrier signal.