Noise shaper variable quantizer
AssigneeSTMicroelectron S.r.l.
InventorFrancesco Stilgenbauer
Life of this patent
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Abstract
A signal processing circuit includes a filter generating a quantizer input signal from a noise shaping input signal and a quantizer output signal. A quantizer divides the quantizer input signal by a scaling factor to produce a noise shaping output signal and multiplies the noise shaping output signal by the scaling factor to produce the quantizer output signal. Receiver circuitry scales the quantizer output signal by a second scaling factor. A dynamic range optimization circuit compares a current value of the noise shaping input signal to a threshold value, lowers or raises the scaling factor in response to the comparison, and proportionally lowers or raises the scaling factor such that a ratio between the scaling factor and second scaling factor remains substantially constant.
Claims20
A signal processing circuit, comprising:
- a transmitter section including a noise shaper, the noise shaper comprising:
- a filter receiving a noise shaping input signal and a quantizer output signal, the filter configured to generate a quantizer input signal based at least upon the noise shaping input signal and the quantizer output signal;
- and
- a quantizer receiving the quantizer input signal and configured to divide the quantizer input signal by a first scaling factor to produce a noise shaping output signal, and to multiply the noise shaping output signal by the first scaling factor to produce the quantizer output signal;
- a receiver section including:
- receiver circuitry receiving the noise shaping output signal, the receiver circuitry configured to scale the quantizer output signal by a second scaling factor;
- and
- a dynamic range optimization circuit configured to:
- determine whether an absolute value of the noise shaping input signal is less than a threshold value;
- lower the first scaling factor in response to the absolute value of the noise shaping input signal being less than the threshold value;
- and
- decrease the second scaling factor in response to the absolute value of the noise shaping input signal being less than the threshold value, proportionally to the lowering of the first scaling factor, such that a ratio between the first scaling factor and the second scaling factor remains substantially constant.
A signal processing method, comprising:
- generating a quantizer input signal based at least upon a noise shaping input signal and a quantizer output signal;
- dividing the quantizer input signal by a first scaling factor to produce a noise shaping output signal, and multiplying the noise shaping output signal by the first scaling factor to produce the quantizer output signal;
- scaling the quantizer output signal by a second scaling factor;
- determining whether an absolute value of the noise shaping input signal is less than a threshold value;
- lowering the first scaling factor in response to the absolute value of the noise shaping input signal being less than the threshold value;
- and
- decreasing the second scaling factor in response to the absolute value of the noise shaping input signal being less than the threshold value, proportionally to the lowering of the first scaling factor such that a ratio between the first scaling factor and the second scaling factor remains substantially constant.
Dependencies are inferred from the claim text.