General Electric Company

Other

David Henry Hoe

David Byrd Ribner

Juha Mikko Hakkarainen

A delta sigma modulator that has a low power dissipation without sacrificing modulator resolution includes, in one embodiment, a current mode digital to analog converter (DAC) in shunt with a conventional op amp in the first stage of the delta sigma modulator. By adding the current mode DAC in shunt with the first (or only) stage op amp of the delta sigma modulator, the slewing current needed during transients is provided by the combination of the op amp and DAC output signals. Since the DAC provides the slewing current required for the output signal change, the op amp need not apply the slewing current and therefore need only operate at low quiescent power.

Low power delta sigma converter

A delta sigma modulator which enables each cascaded integrator to settle independently within a full clock period and uses binomial coefficients in the feedback paths to obtain the required sinusoidal shaping of quantizer error, achieves an increase in both the sampling rate and the order to improve resolution. Using a multi-bit quantizer also improves modulator resolution. In one embodiment, the modulator includes a plurality of cascaded unit-delay integrators and utilizes binomial coefficient scaling in the feedback loop. A multi-bit analog-to-digital converter is coupled to receive the output signal of the cascaded unit-delay integrators. The feedback loop includes a multi-bit digital-to-analog converter coupled to the output of the multi-bit analog-to-digital converter. The output of the digital-to-analog converter is coupled to the inputs of at least the first and second differential summing junctions.

High-order delta sigma analog-to-digital converter with unit-delay

A delta-sigma modulator includes, in one embodiment, cascaded unit-delay integrators, the number of which is selected depending upon the order desired. The modulator further includes an n-bit (or multi-bit) A/D converter coupled to the output of the last cascaded integrator, and an n-bit (or multi-bit) D/A converter coupled to the output of the A/D converter. A truncator also is coupled to the output of the A/D converter. Truncation error correction is performed digitally by a truncation corrector. A one-bit D/A converter provides feedback from the output of the truncator to differential summing junctions interposed at the input of each unit-delay integrator. The multi-bit D/A converter output signal is fed back to differential summing junctions at the input of the third order and higher unit-delay integrators. The multi-bit D/A converter requires no digital correction of its linearity and only unit-delay integrators are used so that N-1 delay free integrators do not all have to settle within one clock period. The modulator therefore utilizes multiple quantizer bits to provide increased converter resolution and is stable at high orders.

High-order delta sigma modulator

An architecture for oversampled delta-sigma (.DELTA.--.SIGMA.) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage .DELTA.--.SIGMA. modulators that incorporate band-reject noise shaping centered at an arbitrary center frequency F.sub.bp. These modulators cascaded with a bandpass digital filter centered at the arbitrary center frequency F.sub.bp perform A/D conversion for high-frequency, narrow-band signals having the same arbitrary frequency. The bandpass modulators are implemented by use of resonators which provide a substantially large gain at the arbitrary frequency.

Analog-to-digital converters using multistage bandpass delta sigma

An architecture for oversampled delta-sigma (.DELTA.-.SIGMA.) analog-to-digital (A/D) conversion of high-frequency, narrow-band signals includes multistage .DELTA.-.SIGMA. modulators that incorporate band-reject noise shaping centered at one fourth the clock frequency Fs. These modulators cascaded with a bandpass digital filter also centered at a frequency of Fs/4 perform A/D conversion for high-frequency, narrow-band signals centered at the same frequency. The bandpass modulators are implemented by use of resonators in existing low-pass multistage modulators.

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Schenectady, NY, United States of America

David Henry Hoe