Sigma-delta modulator and method for operating such modulator

A method for operating a sigma-delta modulation system comprising the steps of:

• feeding an input signal and a test signal into different inputs of a sigma-delta modulator, such modulator providing a common filter for a composite signal comprising the test signal and quantization noise generated in the modulator, such modulator producing an output signal comprising a quantized input signal and the commonly filtered composite signal;
• feeding the modulator output signal to an adaptive quantization noise canceler, such canceler combining the modulator output signal with a quantization noise nulling signal to produce a quantization noise compensated output signal.

A method for operating a sigma-delta modulation system, comprising the steps of:

• concurrently feeding an input signal and a test signal to the sigma-delta modulator to produce a modulator output signal, the modulator providing a common filter for a composite signal comprising the test signal and quantization noise generated in the modulator, the modulator output signal produced therefore includes as components thereof the quantized input signal and the filtered composite signal;
• combining the modulator output signal and the pre-filtered composite signal in an adaptive quantization noise canceler producing a quantization noise nulling signal.

A sigma-delta modulation system, comprising:

• a sigma-delta modulator adapted for having concurrently fed thereto an input signal and a test signal, such modulator providing a common filter for the test signal and quantization noise generated in the modulator in quantizing the input signal, such modulator producing an output signal comprising the quantized input signal and the commonly filtered quantization noise and test signal;
• and
• an adaptive quantization noise canceler for combining the quantization noise and test signal prior to filtering by the common filter with the modulator output signal to produce a quantization noise compensated output signal, such canceler combines the quantization noise and test signal prior to filtering by the common filter and the modulator output signal as a function of the power of the test signal in the quantization noise compensated output signal.

A method for operating a sigma-delta modulator comprising the steps of:

• concurrently feeding an input signal and a test signal to the modulator to produce an output signal, such modulator providing a common filter for the test signal and quantization noise generated in the modulator, such output signal comprising the quantized input signal and the commonly filtered quantization noise and test signal;
• combining the quantization noise and test signal prior to filtering by the common filter with the output signal to produce a corrected output signal, the quantization noise and test signal, prior to filtering by the common filter, and the output signal being combined as a function of the power of the test signal in the corrected output signal.

A sigma-delta modulation system, comprising:

• a sigma-delta modulator concurrently fed by an input signal and a test signal to produce an output signal, such modulator providing a common filter for the test signal and quantization noise generated in the modulator in quantizing the input signal, such output signal comprising the quantized input signal and the commonly filtered quantization noise and test signal;
• a combiner for combining the quantization noise and test signal prior to filtering by the common filter with the output signal to produce an corrected output signal, the quantization noise and test signal prior to filtering by the common filter and the output signal being combined as a function of the power of the test signal in the corrected output signal.

A method for operating a sigma-delta modulator comprising the steps of:

• concurrently feeding an input signal and a test signal to the modulator to produce an output signal;
• correlating the output signal with the injected test signal to produce an error correction signal;
• modifying the output signal in accordance with the produced error correction signal.