Pulse modulator and pulse modulation method
AssigneeLITEF GmbH
InventorGuenter Spahlinger
Life of this patent
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Abstract
A pulse modulator has a subtraction stage that produces a control error signal from the difference between a complex input signal and a feedback signal. A signal conversion stage converts the control error signal to a control signal. The control signal is multiplied by a complex mixing signal at the frequency ω0 in a first multiplication stage. At least one of the real and imaginary parts of the up-mixed control signal is then quantized by a quantization stage to produce a real pulsed signal. The pulsed signal is then employed to produce the feedback signal for the subtraction stage in a feedback unit. The pulse modulator according to the invention allows the range of reduced quantization noise to be shifted toward a desired operating frequency ω0.
Claims61
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A drive circuit for a micromechanical resonator, which has at least one pulse modulator for conversion of a complex input signal to a pulsed signal, and which has:
- a subtraction stage which produces a control error signal from the difference between the complex input signal and a feedback signal;
- a single conversion stage, which converts the control error signal to a control signal;
- a first multiplication stage, which multiplies the control signal by a complex mixing signal oscillating at the frequency ω0, and thus produces at least one of a real part and an imaginary part of a control signal which has been up-mixed by ω0,
- a quantization stage, which quantizes at least one of the real part and imaginary part of the control signal which has been up-mixed by ω0 and thus produces the pulsed signal, with the pulsed signal which is produced by the at least one pulse modulator being used for electrostatic oscillation stimulation of a resonator, and with the pulse modulator being operated at a sampling frequency ωA which is 2 to 1000 times higher than the mixing frequency ω0,
- a feedback unit, which uses the pulsed signal to produce the feedback signal for the subtraction stage.
A frequency generator for synthesis of a pulsed signal at a predetermined frequency and with a predetermined phase, which has at least one pulse modulator for conversion of a complex input signal to a pulsed signal and which has:
- a subtraction stage which produces a control error signal from the difference between the complex input signal and a feedback signal,
- a single conversion stage, which converts the control error signal to a control signal;
- a first multiplication stage, which multiplies the control signal by a complex mixing signal oscillating at the frequency ω0, and thus produces at least one of a real part and an imaginary part of a control signal which has been up-mixed by ω0, with the pulse modulator being operated at a sampling frequency ωA which is 2 to 1000 times higher than the mixing frequency ω0;
- a quantization stage, which quantizes at least one of the real part and imaginary part of the control signal which has been up-mixed by ω0 and thus produces the pulsed signal;
- a feedback unit, which uses the pulsed signal to produce the feedback signal for the subtraction stage.
The frequency generator as claimed in claimed 47, characterized in that the feedback unit has a second multiplication stage, which multiplies the pulsed signal by a complex-conjugate mixing signal oscillating at the frequency ω0, and thus produces the feedback signal down-mixed by ω0, for the subtractor.
A method for pulse modulation of a complex input signal, characterized by the following steps:
- production of a control error signal from the difference between the complex input signal and a feedback signal;
- conversion of the control error signal to a control signal;
- multiplication of the control signal by a complex mixing signal oscillating at the frequency ω0, with at least one of the real part and imaginary part of a control signal, up-mixed by ω0, being produced;
- quantization of at least one of the real part and imaginary part of the control signal, up-mixed by ω0, in order to produce a pulsed signal, with the pulsed signal being used for electrostatic oscillation stimulation of a micromechanical resonator, and with the pulse modulation being carried out at a sampling frequency ωA which is 2 to 1000 times higher than the mixing frequency ω0;
- production of the feedback signal from the pulsed signal.
Dependencies are inferred from the claim text.