Jointly nonlinear delta sigma modulators
First Claim
1. A signal processing system comprising:
- a jointly nonlinear delta sigma modulator comprising;
a noise shaping filter to process a signal and generate N state variables, wherein N is greater than or equal to two; and
a quantizer to quantize quantizer input data determined from at least a subset of the N state variables in accordance with a nonlinear quantization transfer function, wherein one or more boundaries between quantization regions for at least one quantization level are characterized at least in part by a nonlinear interrelationship between at least two of the state variables.
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Abstract
A signal processing system includes a jointly non-linear delta sigma modulator. In one embodiment, the jointly non-linear delta sigma modulator includes a non-linear quantization transfer function, and the output of the delta sigma modulator is defined, at least in part, by a non-linear interrelationship of multiple noise-shaping filter state variables. A look-ahead delta-sigma modulator can be implemented as a noise shaping filter and a function generator. State variables of the noise shaping filter provide the input data from which the function generator determines a quantizer output signal. Latter state variables are more dominant in determining the quantizer output signal. Accordingly, earlier state variables can be approximated to a greater degree than latter state variables without significant compromise in quantization accuracy.
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Citations
25 Claims
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1. A signal processing system comprising:
a jointly nonlinear delta sigma modulator comprising;
a noise shaping filter to process a signal and generate N state variables, wherein N is greater than or equal to two; and
a quantizer to quantize quantizer input data determined from at least a subset of the N state variables in accordance with a nonlinear quantization transfer function, wherein one or more boundaries between quantization regions for at least one quantization level are characterized at least in part by a nonlinear interrelationship between at least two of the state variables. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of processing a signal using a jointly nonlinear delta-sigma modulator that includes a noise shaping filter having N state variables, the method comprising:
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filtering an input signal to the jointly nonlinear delta-sigma modulator using the noise shaping filter to generate respective quantizer input data from the N state variables, wherein N is greater than or equal to two; and
quantizing the quantizer input data in accordance with a nonlinear quantization transfer function, wherein one or more boundaries between quantization regions for at least one quantization level are characterized at least in part by a nonlinear interrelationship between at least two of the state variables. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of quantizing an input signal using non-linearly related input data and a nonlinear quantization transfer function, the method comprising:
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receiving input signal samples;
filtering the input signal samples to generate digital filter state variables; and
applying a nonlinear quantization transfer function to at least a subset of the state variables to generate an output signal, wherein one or more boundaries between quantization regions for at least one quantization level are characterized at least in part by a nonlinear interrelationship between at least two of the state variables. - View Dependent Claims (24)
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25. An apparatus comprising:
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means to filter input signal samples to generate digital filter state variables representing state variables of a multi-order digital filter; and
means to quantize at least a subset of the state variables using a nonlinear quantization transfer function, wherein one or more boundaries between quantization regions for at least one quantization level are characterized at least in part by a nonlinear interrelationship between at least two of the state variables.
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Specification