Abstract: A delta-sigma modulator is disclosed which has a filter comprising a filter input, two LC resonators (LC1-1, LC1-2), and two switches (CBT/CGT). An input of each one of the two switches is connected to the filter input and a corresponding output of each one of the two switches is connected to a corresponding one of said LC resonators. Each one of the two switches is individually controllable for selectively connecting the corresponding one of the LC resonators with the filter input. The invention also relates to a method for changing the mode of operation of a delta-sigma modulator.

Abstract: The application relates to a calibration apparatus and calibration method for a tuneable resonator of a delta-sigma modulator of the continuous time, band pass type. The calibration apparatus comprises: a resonator driver capable of causing an oscillating behavior in a resonator output signal, a reference signal source that provides a reference signal, a frequency detector that provides a frequency relation signal corresponding to the frequency relation between the resonator output signal and the reference signal, and a controller that controls the tuneable resonator in dependence from the frequency relation signal so as to reduce frequency deviation.

Abstract: A delta-sigma modulator is disclosed which has a filter comprising a filter input, two LC resonators (LC1-1, LC1-2), and two switches (CBT/CGT). An input of each one of the two switches is connected to the filter input and a corresponding output of each one of the two switches is connected to a corresponding one of said LC resonators. Each one of the two switches is individually controllable for selectively connecting the corresponding one of the LC resonators with the filter input. The invention also relates to a method for changing the mode of operation of a delta-sigma modulator.

Abstract: The application relates to a calibration apparatus and calibration method for a tuneable resonator of a delta-sigma modulator of the continuous time, band pass type. The calibration apparatus comprises: a resonator driver capable of causing an oscillating behaviour in a resonator output signal, a reference signal source that provides a reference signal, a frequency detector that provides a frequency relation signal corresponding to the frequency relation between the resonator output signal and the reference signal, and a controller that controls the tuneable resonator in dependence from the frequency relation signal so as to reduce frequency deviation.

Abstract: An amplifier (10) comprises a digitally clocked automatic gain control loop (11, 12, 13, 14). A Pseudo random clock generator (14) generates the clock signals for the loop. The application introduces a scheme which reduces sidebands caused by digital gain control loops. The effect of gain control on a system can be seen as amplitude modulation on the signal whose amplitude is controlled. This amplitude modulation causes the same sidebands that are commonly seen with AM modulation. This invention introduces a novel method that alleviates AM sidebands for a digitally controlled gain control loop.