Sigma-delta modulation device and sigma-delta modulation method
AssigneeRealtek Semiconductor Corp.
InventorChen-Fong Liao
Life of this patent
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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.
Claims15
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.
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.
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.
Dependencies are inferred from the claim text.