Sigma-delta modulation device and sigma-delta modulation method

Patent metadata

Field	Value
Publication number	US-11418211-B2
Application number	US-202117199906-A
Country	US
Kind code	B2
Filing date	Mar 12, 2021
Priority date	Aug 14, 2020
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

A sigma-delta modulation device includes a detection circuit and a sigma-delta modulator. The detection circuit is configured to detect an input signal to generate a detection signal, and compare the detection signal and a threshold to generate a control signal. The sigma-delta modulator is coupled to the detection circuit and configured to store a plurality of noise transfer functions, select one of the noise transfer functions according to the control signal, and convert the input signal into an output signal according to the noise transfer function.

First claim

What is claimed is:

1. A sigma-delta modulation device, comprising:
a detection circuit configured to detect an input signal to generate a detection signal, and compare the detection signal with a threshold to generate a control signal; and
a sigma-delta modulator coupled to the detection circuit and configured to store a plurality of noise transfer functions, select one of the noise transfer functions according to the control signal, and convert the input signal into an output signal according to the selected noise transfer function,
wherein the plurality of noise transfer functions comprises a first noise transfer function and a second first noise transfer function, and
wherein a first input upper-bound of the first noise transfer function is smaller than a second input upper-bound of the second noise transfer function, and a first total harmonic distortion plus noise of the first noise transfer function is smaller than a second total harmonic distortion plus noise of the second noise transfer function.

2. The sigma-delta modulation device of claim 1 , wherein the detection circuit comprises:
an envelope detector configured to receive the input signal and detect the amplitude variation of the input signal in order to generate the detection signal; and
a comparison circuit configured to receive the detection signal and compare the detection signal with the threshold in order to generate the control signal.

3. The sigma-delta modulation device of claim 2 , wherein the comparison circuit is configured to generate a first control signal in response to the detection signal being not larger than the threshold and generate a second control signal in response to the detection signal being larger than the threshold.

4. The sigma-delta modulation device of claim 3 , wherein the sigma-delta modulator is configured to select the first noise transfer function according to the first control signal and select the second noise transfer function according to the second control signal.

5. The sigma-delta modulation device of claim 1 , wherein the sigma-delta modulator selects the first noise transfer function in response to the detection signal being not larger than the threshold, the sigma-delta modulator selects the second noise transfer function in response to the detection signal being larger than the threshold.

6. A sigma-delta modulation method applicable to a sigma-delta modulation device comprising a sigma-delta modulator configured to store a plurality of noise transfer functions, wherein the sigma-delta modulation method comprises:
detecting an input signal of the sigma-delta modulator to generate a detection signal;
comparing the detection signal with a threshold to generate a control signal;
selecting one of the noise transfer functions according to the control signal; and
converting the input signal into an output signal according to the selected noise transfer function,
wherein the plurality of noise transfer functions comprises a first noise transfer function and a second first noise transfer function, and
wherein a first input upper-bound of the first noise transfer function is smaller than a second input upper-bound of the second noise transfer function, and a first total harmonic distortion plus noise of the first noise transfer function is smaller than a second total harmonic distortion plus noise of the second noise transfer function.

7. The sigma-delta modulation method of claim 6 , wherein generating the detection signal comprises:
detecting, by an envelope detector, an amplitude variation of the input signal to generate the detection signal.

8. The sigma-delta modulation method of claim 6 , wherein generating the detection signal comprises:
detecting, by an envelope detector, a duty cycle of the input signal to generate the detection signal.

9. The sigma-delta modulation method of claim 6 , wherein generating the detection signal comprises:
detecting, by an envelope detector, a time duration of a signal pulse of the input signal to generate the detection signal.

10. The sigma-delta modulation method of claim 6 , wherein comparing the detection signal with the threshold to generate the control signal comprises:
comparing, by a comparison circuit, the detection signal with the threshold;
generating, by the comparison circuit, a first control signal in response to the detection signal being not larger than the threshold; and
generating, by the comparison circuit, a second control signal in response to the detection signal being larger than the threshold.

11. The sigma-delta modulation method of claim 10 , further comprising:
selecting, by the sigma-delta modulator, the first noise transfer function according to the first control signal; and
selecting, by the sigma-delta modulator, the second noise transfer function according to the second control signal.

12. The sigma-delta modulation method of claim 6 , further comprising:
selecting the first noise transfer function in response to the detection signal being not larger than the threshold; and
selecting the second noise transfer function in response to the detection signal being larger than the threshold.

13. A sigma-delta modulation method applicable to a sigma-delta modulation device comprising a sigma-delta modulator configured to store a plurality of noise transfer functions, wherein the sigma-delta modulation method comprises:
detecting an amplitude variation of an input signal of the sigma-delta modulator;
comparing the amplitude variation with an amplitude threshold to generate a control signal;
selecting one of the noise transfer functions according to the control signal; and
converting the input signal into an output signal according to the selected noise transfer function,
wherein the plurality of noise transfer functions comprises a first noise transfer function and a second first noise transfer function, and
wherein a first input upper-bound of the first noise transfer function is smaller than a second input upper-bound of the second noise transfer function, and a first total harmonic distortion plus noise of the first noise transfer function is smaller than a second total harmonic distortion plus noise of the second noise transfer function.

14. The sigma-delta modulation method of claim 13 , wherein comparing the amplitude variation with an amplitude threshold to generate the control signal comprises:
comparing, by a comparison circuit, the detection signal with the threshold;
generating, by a comparison circuit, a first control signal in response to the amplitude variation being not larger than the amplitude threshold; and
generating, by a comparison circuit, a second control signal in response to the amplitude variation being larger than the amplitude threshold.

15. The sigma-delta modulation method of claim 14 , further comprising:
selecting, by the sigma-delta modulator, the first noise transfer function according to the first control signal; and
selecting, by the sigma-delta modulator, the second noise transfer function according to the second control signal.

Assignees

• Realtek Semiconductor Corp

Inventors

• Liao Chen-Fong

Classifications

• H03M3/358 Primary

  of non-linear distortion, e.g. instability (avoiding instability by structural design H03M3/44) · CPC title

• H03M3/458

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

• H03M3/392

  Arrangements for selecting among plural operation modes, e.g. for multi-standard operation · CPC title

• H03M3/396 Primary

  among different frequency bands · CPC title