Quantizer with sigma-delta modulator, analog-to-digital converter including the same and quantization method using the same

Patent metadata

Field	Value
Publication number	US-9054738-B2
Application number	US-201414286699-A
Country	US
Kind code	B2
Filing date	May 23, 2014
Priority date	May 24, 2013
Publication date	Jun 9, 2015
Grant date	Jun 9, 2015

Abstract

The present invention provides a quantizer with a sigma-delta modulator, an analog-to-digital converter including the same and a quantization method using the same capable of obtaining a high signal-to-noise ratio with a relatively small number of comparators. The quantizer, the analog-to-digital converter and the quantization method of the present invention reduces quantization errors and increases noise shaping order.

First claim

What is claimed is:

1. A quantizer comprising:
a signal interpolator configured to interpolate a first sample through an N th sample included in a sampled signal to generate an interpolated signal;
a sigma-delta modulator configured to subject the interpolated signal to a sigma-delta modulation to generate a sigma-delta modulated signal;
an averaging filter configured to average the sigma-delta modulated signal to generate an average signal;
a downsampler configured to downsample the average signal;
an integrator configured to integrate an output signal of the downsampler; and
a subtractor configured to input a difference between an output signal of the integrator and the sampled signal to the signal interpolator (where N is a natural number).

2. The quantizer in accordance with claim 1 , wherein the signal interpolator comprises an M-times sample repeater configured to generate (M×N) samples by repeating each of the first sample through the N th sample M times (where M is a natural number).

3. The quantizer in accordance with claim 2 , wherein the downsampler comprises an M-times downsampler configured to downsample the average signal by M times.

4. The quantizer in accordance with claim 2 , wherein the sigma-delta modulator comprises a comparator unit and a sigma-delta loop connected between an input terminal and an output terminal of the comparator unit.

5. The quantizer in accordance with claim 4 , wherein the sigma-delta modulator is configured to compare an amplitude of each of the (M×N) samples with a threshold of the comparator unit to output a first pulse signal through an N th pulse signal corresponding to differences between the threshold and the amplitude of each of the (M×N) samples as the sigma-delta modulated signal.

6. The quantizer in accordance with claim 5 , wherein the averaging filter generates the average signal obtained by averaging each of the first pulse signal through the N th pulse signal.

7. A quantization method comprising:
(a) interpolating a first sample through an N th sample included in a sampled signal to generate an interpolated signal;
(b) subjecting the interpolated signal to a sigma-delta modulation to generate a sigma-delta modulated signal;
(c) averaging the sigma-delta modulated signal to generate an average signal;
(d) downsampling the average signal generated in the step (c);
(e) integrating a signal obtained by downsampling the average signal in the step (d); and
(f) interpolating a difference between the signal in the step (e) and the sampled signal (where N is a natural number).

8. The method in accordance with claim 7 , wherein the step (a) comprises repeating each of the first sample through the N th sample M times to generate (M×N) samples (where M is a natural number).

9. The method in accordance with claim 8 , wherein the step (d) comprises downsampling the average signal by M times.

10. The method in accordance with claim 8 , wherein the step (b) comprises comparing an amplitude of each of the (M×N) samples with a threshold value to output a first pulse signal through an N th pulse signal corresponding to differences between the threshold value and the amplitude of each of the (M×N) samples.

11. The method in accordance with claim 10 , wherein the step (c) comprises generating the average signal obtained by averaging each of the first pulse signal through the N th pulse signal.

12. An analog-to-digital converter capable of converting an analog signal to a digital signal, comprising a quantizer including a signal interpolator configured to interpolate a first sample through an N th sample included in a sampled signal to generate an interpolated signal; a sigma-delta modulator configured to subject the interpolated signal to a sigma-delta modulation to generate a sigma-delta modulated signal; an averaging filter configured to average the sigma-delta modulated signal to generate an average signal; and a downsampler configured to downsample the average signal; an integrator configured to integrate an output signal of the downsampler; and a subtractor configured to input a difference between an output signal of the integrator and the sampled signal to the signal interpolator (where N is a natural number).

13. The analog-to-digital converter in accordance with claim 12 , wherein the signal interpolator comprises an M-times sample repeater configured to generate (M×N) samples by repeating each of the first sample through the N th sample M times (where M is a natural number).

14. The analog-to-digital converter in accordance with claim 13 , wherein the downsampler comprises an M-times downsampler configured to downsample the average signal.

15. The analog-to-digital converter in accordance with claim 13 , wherein the sigma-delta modulator comprises a comparator unit and a sigma-delta loop connected between an input terminal and an output terminal of the comparator unit.

16. The analog-to-digital converter in accordance with claim 15 , wherein the sigma-delta modulator is configured to compare an amplitude of each of the (M×N) samples with a threshold value of the comparator unit to output a first pulse signal through an N th pulse signal corresponding to differences between the threshold value and the amplitude of each of the (M×N) samples as the sigma-delta modulated signal.

17. The analog-to-digital converter in accordance with claim 16 , wherein the averaging filter generates the average signal obtained by averaging the first pulse signal through the N th pulse signal.

Assignees

• Snu R&Db Foundation
• Neofidelity Inc

Inventors

• Cho Junsoo
• Lee Hyunjoong
• Kim Suhwan

Classifications

• H03M3/462 Primary

  Details relating to the decimation process (decimation filters in general H03H17/0416, H03H17/0621) · CPC title

• H03M1/002

  Provisions or arrangements for saving power, e.g. by allowing a sleep mode, using lower supply voltage for downstream stages, using multiple clock domains or by selectively turning on stages when needed · CPC title

• H03M3/02

  Delta modulation, i.e. one-bit differential modulation {(H03M3/30 takes precedence)} · CPC title

• H03M1/203

  using an analogue interpolation circuit · CPC title

• H03M3/458

  Analogue/digital converters using delta-sigma modulation as an intermediate step · CPC title