Abstract:
A transceiver includes a processor and an analog-to-digital converter. The processor is adapted to in a transmit mode of the transceiver, generate a modulated signal in response to a first digital signal. In a receive mode of the transceiver, the processor is adapted to generate a demodulated signal in response to a second digital signal. The analog-to-digital converter provides the first digital signal in the transmit mode and provides the second digital signal in the receive mode.
Abstract:
A noise-shaping coder with variable or reconfigurable characteristics is disclosed. In one exemplary embodiment, an improved apparatus for signal modulation is disclosed. The apparatus (see figure 1) generally comprises a noise-shaping coder having programmable coefficients, (see figure 1, CSEL), programmable coder order (see figure 1, MSEL), programmable oversampling frequency (see figure 1, CKEN), and/or programmable dither (see figure 1, D). In a second exemplary embodiment, an improved method for implementing noise shaping coding is disclosed. The apparatus generally compromises a means for switching from one order coder to another order coder, as well as switching oversampling frequency.
Abstract:
Several delta-sigma modulator circuits and a single quantizer provide analog-to-digital conversionfor mulitple frequency bands. A wideband mode is provided by coupling an analog signal to bedigitized directly to quantizer. Narrowband modes are provided by switching the analog signalto be digitized into one of several delta-sigma modulator circuits. Noise shaping and filtering bythe delta-sigma modulator circuits result in improved signal-to-noise-and-distortion performanceand increased resoulution. Performance is further enhanced by feeding back multiple bits outputby the quantizer to the delta-sigma modulator circuits. The delta-sigma modulator circuits can beeither continuous time or discrete time delta sigma modulators.
Abstract:
A method and system are disclosed for operating two or more integrator amplifiers with different power supplies for a modulator of an analog-to-digital ("A/D") converter. A first, upstream integrator (int1) is operated with one power supply, and the other downstream integrator(s) is/are operated with at least another power supply (INT2). The modulator has amplifiers with coefficient gains having values that are determined and set so that voltage levels for the at least another integrator are maintained within operating and output limits. An integrating coefficient gain (K1) for the first integrator is set to have a sufficiently large value so that an integrating capacitor can be made small for the one integrator. Another integrating coefficient gain (K2) for a second integrator is set to have a sufficiently small value so that an output voltage from the first integrator is sufficiently attenuated to a voltage value within an operating range of the second integrator.
Abstract:
In accordance with the exemplary embodiments of the invention there is at least an apparatus to perform a method includingreceiving by an analog-to-digital converter a signal; determining whether an in-band blocker is present in the signal; andadjusting a transfer function of the analog-to-digital converter based on whether an in-band blocker is present by configuring a loop filter of the analog-to-digital converter.
Abstract:
A continuous-time sigma-delta analog-to-digital converter (CV) comprises i) a signal path (SP) comprising at least one combiner (Cl) for combining analog signals to convert with feedback analog signals, at least two integrators (Hl, H5), mounted in series, to integrate the combined analog signals, a quantizer (Q) for converting the integrated signals into digital signals, and a decimation filter (DF) for filtering digital signals, and ii) a feedback path (FP) comprising at least a digital-to-analog converter (DAC) for converting the digital signals output by the quantizer (Q) into feedback analog signals intended for the combiner (Cl). Each integrator (Hl, H5) comprises variable capacitance means arranged to be set in chosen states define by the values of a digital word, to present chosen capacitances. The converter (CV) also comprises a self-calibration control means (CCM) arranged a) to generate a digital word with a chosen first value, b) to estimate an in-band noise IBN(n) from the filtered digital signals and to compare this IBN(n) to the preceding IBN(n-l), c) to modify the digital word value to decrease the capacitance of each integrator from a chosen decrement when IBN(n) is smaller than IBN(n-l), d) to iterate steps b) and c) till IBN(n) be greater than IBN(n-l), and to choose as calibration digital word value the value corresponding to IBN(n- 1) to set the calibration state of the variable capacitance means.
Abstract:
A sigma delta modulator includes a modulator module that includes a quantizer with variable hysteresis, which receives an input signal to perform necessary modulation operations. A non-linear mapping module receives a signal associated with said input signal and tabulates the necessary hysteresis control information so as to reduce the transition rate of the modulator module.
Abstract:
A method and system are disclosed for operating two or more integrator amplifiers with different power supplies for a modulator of an analog-to-digital ("A/D) converter. A first, upstream integrator is operated with one power supply, and the other downstream integrator(s) is/are operated with at least another power supply. The modulator has amplifiers with coefficient gains having values that are determined and set so that voltage levels for the at least another integrator are maintained within operating and output limits. An integrating coefficient gain k1 for the first integrator is set to have a sufficiently large value so that an integrating capacitor can be made small for the one integrator. Another integrating coefficient gain k2 for a second integrator is set to have a sufficiently small value so that an output voltage from the first integrator is sufficiently attenuated to a voltage value within an operating range of the second integrator.
Abstract:
La présente inventive concerne un modulateur sigma-delta comprenant au moins un résonateur (110a, 110b), un convertisseur (120) pour convertir un signal analogique en provenance du résonateur en un signal numérique à information temporelle, et une boucle de rétroaction reliant une sortie du convertisseur une entrée d'excitation du résonateur. Conformément à l'invention, au moins un résonateur du modulateur est un résonateur choisi dans le groupe comprenant les résonateurs mécaniques, acoustiques, électromécaniques, électrostatiques, optiques et chimiques. Application à la conversion analogique-numérique, à la détection et à la génération de signaux.