Abstract:
A control system for the characteristic parameters of an active filter includes: a system for the determination of the technological distribution of the components that provides the information related to said technological distribution of the components; an elaboration system for said information related to said technological distribution of the components; an active filter including at least two programmable passive circuital elements receiving said information related to said technological distribution of the components; said elaboration system, being aware of the topology for said active filter, comprises means for determining the value for said at least two programmable passive circuital elements; means for correcting the value for said at least two programmable passive circuital elements according to the value of the information related to said technological distribution of the components; means for determining the programming values for said at least two programmable passive circuital elements.
Abstract:
A sigma-delta-type converter comprises: a sigma-delta modulator having a digital output having a first prefixed bit number; a randomizer including a circular memory; an analogical reconstruction filter comprising a branch number equal to said first default number including sampling capacitors and a low-pass filter; characterized in that said circular memory comprises a number of elements equal to said first default number of bits less one and receives in input said first default number of bits less one, and in that a bit of said first default number of bits is applied to one of said branches of said reconstruction filter.
Abstract:
A method for digital-to-analog conversion of a digital input code into a first output analog signal and a second output analog signal to be supplied to a first terminal and a second terminal, respectively, of an audio load, the conversion being performed by means of a DAC with N-level balanced output, the conversion method includes using N/2 positive generator elements supplying respective positive elementary contributions which are nominally equal to one another, and N/2 negative generator elements supplying respective negative elementary contributions which are nominally equal to one another and, in absolute value, equal to the positive elementary contributions; attributing the same progressive addresses to the positive generator elements and to the negative generator elements; defining a first index for the positive input codes and a second index for the negative input codes; and, in the presence of an input code at the input of the DAC, selecting between the first index and the second index, the index corresponding to the sign of the input code; activating a first set of positive generator elements and a second set of negative generator elements, the number of the positive generator elements activated and the number of the negative generator elements activated being equal to one another and proportional to the input code, and the addresses of the positive generator elements activated and of the negative generator elements activated being a function of the selected index; generating the first output analog signal by summing the positive elementary contributions supplied by the positive generator elements activated, and generating the second output analog signal by summing the negative elementary contributions supplied by the negative generator elements activated; and updating the selected index according to the input code.
Abstract:
A method of self-calibrating a modulator includes at least one integrator likely to incur a phase error may include reading a pulse response of the modulator, calculating a phase error parameter of the at least one integrator, and calibrating the phase error parameter. In addition, the calibration may provide a count of pulse response samples above suitable threshold values, as well as a change in the value of a capacitor associated with the integrator based upon the sample count.
Abstract:
A continuous-time filter comprising at least one amplifier and at least one passive element. The amplifier comprises at least one input terminal and at least one output terminal and the passive element is positioned between the terminals. In addition the amplifier is provided with a transconductance gain. The filter comprises circuit means suitable for correlating the transconductance gain of the amplifier with the passive element.