Quantization noise cancellation in a feedback loop
AssigneeAnalog Devices, Inc.
InventorsArthur J. Kalb, Yogesh Jayaraman Sharma, Marvin Liu Shu
Life of this patent
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Abstract
An analog front end (AFE) system for substantially eliminating quantization error or noise can combine an input of an integrator circuit in the AFE system with an input of the digital-to-analog converter (DAC) circuit in the feedback loop of the AFE system. By combining the input of the integrator with the input of the DAC circuit in the feedback loop, the in-band quantization noise of the filter can be substantially eliminated, thereby improving measurement accuracy.
Claims24
An analog front end (AFE) system for compensating quantization error, the AFE system comprising:
- a gain circuit including a first input configured to receive an input signal, a second input configured to receive a feedback signal using a feedback path, and an output configured to provide an amplified version of the difference between the input signal and the feedback signal;
- an analog-to-digital converter (ADC) configured to receive a gain circuit output signal and output a digital output signal;
- a digital frequency-selective filter circuit configured to receive the ADC digital output signal and output a quantized filter circuit output signal;
- a digital-to-analog converter (DAC) circuit, the DAC circuit configured to receive the filter output signal and output the feedback signal to the second input of the gain circuit;
- and
- an AFE system output circuit configured to combine the ADC output signal and the filter circuit output signal, and output a quantization error-compensated AFE output signal.
A method of analog-to-digital conversion that compensates for a quantization error component of the conversion, the method comprising:
- receiving an analog input signal for conversion into a digital output signal;
- combining the analog input signal with a feedback signal to create difference signal;
- amplifying the difference signal;
- performing an analog-to-digital conversion on the amplified signal to create a converted digital signal;
- filtering the converted digital signal to generate a filtered signal with quantization error;
- performing a digital-to-analog conversion on the filtered signal to generate the feedback signal;
- and
- combining the converted digital signal with the filtered signal to generate a system output in which the quantization error component is substantially reduced.
An electrocardiogram (ECG) measurement circuit comprising:
- an analog front end (AFE) system for compensating quantization error, the AFE system including:
- a gain circuit including a first input configured to receive an input signal and a second input configured to receive a feedback signal using a feedback path;
- an ADC circuit configured to receive a gain circuit output signal and output an ADC circuit output signal;
- a frequency-selective filter circuit configured to receive the ADC circuit output signal and output a filter circuit output signal;
- a quantizer circuit, the quantizer circuit configured to receive the filter circuit output signal and output a quantized signal;
- a digital-to-analog converter (DAC) circuit, the DAC circuit configured to receive the quantized signal and output the feedback signal to the second input of the gain circuit;
- and
- an AFE system output circuit configured to combine the ADC circuit output signal and the quantized signal and output a quantization error-compensated AFE output signal.
Dependencies are inferred from the claim text.