US 5,748,126 A · Sigma-delta digital-to-analog conversion system and process through reconstruction and resampling

Abstract

A conversion system and method is disclosed for converting between digital and analog data signals. The conversion system comprises a signal input line for each digital data signal, a reconstructor-resampler unit for each digital data signal, a combiner, a modulator, a digital-to-analog converter, and a signal output line. Each signal line input couples to the respective reconstructor-resampler unit for the digital data signal. Each reconstructor-resampler unit then couples to a combiner which couples to a modulator. The modulator couples to the digital-to-analog converter that couples to the signal output line from which an analog output signal is produced. The reconstructor-resampler comprises a sampling member coupled to the signal line input and a polynomial interpolator member coupled to the sampling member and the modulator. Also, the modulator operates at a predetermined, or fixed, frequency regardless of the sampling frequency of the digital data signal. The steps of the conversion method include inputting a digital data signal having a sampling frequency, reconstructing and resampling the digital data signal to generate a resampled data signal, performing noise-shaping on the resampled data signal to generate a x-bit data signal from a modulator operating at a predetermined frequency regardless of the sampling frequency of any of the digital data signals, and converting the x-bit data signal to an analog data signal. In addition, an analog-to-digital conversion system and method is disclosed that comprises a signal line input, a decimator, a reconstructor-resampler a signal output line, and a modulator operating at a predetermined frequency to convert an analog data signal to a digital data signal.

Claims33

Dependent claims

In a digital-to-analog conversion system including an input of a digital data signal, having a sampling frequency, and including a digital-to-analog converter and a modulator operating at a fixed clock rate regardless of the sampling frequency, a method to convert the digital data signal to an analog data signal comprising the steps of:

receiving the digital data signal at a signal input line;
reconstructing and resampling the digital data signal to generate a resampled data signal, the reconstructing and resampling further comprising
upsampling the digital data signal to generate an upsampled digital data signal;
and
curve-fitting the upsampled digital data signal using polynominal interpolation to generate the resampled data signal;
performing noise-shaping on the resampled data signal to generate a x-bit data signal;
converting the x-bit digital data signal to the analog data signal;
and
outputting the analog data signal.

6 more elements

A digital-to-analog conversion system, for converting a digital data signal, having a sampling frequency, to an analog data signal, the system comprising:

a reconstructor-resampler, having an input and an output, for a sampling rate conversion of the digital data signal to generate a resampled data signal, the input of the reconstructor-resampler coupled to receive the digital data signal, the reconstructor-resampler including
a sampling member, having an input and an output for upsampling the digital data signal to generate an upsampled digital data signal the input of the sampling member coupled to receive the digital data signal input into the reconstructor-resampler;
and
a polynomial interpolator, having an input and an output for interpolating the upsampled digital data signal to generate the resampled data signal the input of the polynomial interpolator coupled to the output of the sampling member and the output of the polynomial interpolator coupled as the output from the reconstructor-resampler;
a modulator, having an input, an output, and a clock signal input, for performing noise-shaping on the resampled data signal to generate a x-bit data signal, the input of the modulator coupled to the output of the reconstructor-resampler to receive the resampled data signal, the clock input of the modulator coupled to receive a clock signal for operating the modulator at a predetermined clock rate;
and,
a digital-to-analog converter, having an input and an output for converting the x-bit data signal to generate an analog data signal, the input of the digital-to-analog converter coupled to the output of the modulator for receiving the x-bit data signal and the output of the digital-to-analog converter coupled to output the analog data signal.

4 more elements

A digital-to-analog conversion system for converting a first digital data signal, having a first sampling frequency, and a second digital data signal, having a second sampling frequency, to an analog data signal, the system comprising:

a first reconstructor-resampler, having an input and an output, for sampling rate conversion of the first digital data signal to generate a first resampled data signal, the input of the first reconstructor-resampler coupled to receive the first digital data signal;
a second reconstructor-resampler, having an input and an output, for a sampling rate conversion of the second digital data signal to generate a second resampled data signal, the input of the second reconstructor-resampler coupled to receive the second digital data signal;
a combiner, having a first input, a second input, and an output, for combining the first resampled data signal and the second resampled data signal to generate a combined data signal, the first input of the combiner coupled to the output of the first reconstructor-resampler for receiving the first resampled data signal and the second input of the combiner coupled to the output of second reconstructor-resampler for receiving the second resampled data signal;
a modulator, having an input, an output and a clock signal input, for performing noise-shaping on the combined data signal to generate a x-bit data signal, the input of the modulator coupled to the output of the combiner to receive the combined data signal, the clock input of the modulator coupled to a clock for operating the modulator at a predetermined frequency;
and
a digital-to-analog converter, having an input and an output, for converting the x-bit data stream to the analog data signal, the input of the digital-to-analog converter coupled to the output of the modulator for receiving the x-bit data stream and the output of the digital-to-analog converter coupled to output the analog data signal.

3 more elements

Dependencies are inferred from the claim text.

Sigma-delta digital-to-analog conversion system and process through reconstruction and resampling

Life of this patent

Sigma-delta digital-to-analog conversion system and process through reconstruction and resampling

Life of this patent

Abstract

Claims33