Non-linear error correcting method for multiple position quantizer used in sigma Delta A/D and D/A converter

Abstract

Characters of the method are that using random action of switch to turn on/off the switching capacitors in DAC with multiple bits so as to introduce random noise to smooth nonlinear distortion caused by mismatch of capacitive component; next, introduced random noise raises background noise in signal bandwidth; then, carrying out noise shaping based on the raised background noise to push noise inside signal bandwidth to outside signal bandwidth so as to raise SNR of system effectively. The invention disclosed whole digit method is in use for correcting non-linear error caused by mismatch of capacitive in order to raise stability of modulator and SNR of converter, which use Sigma-Delta A/D and D/A converters in quantification mode with multiple bits.

Description

technical field [0001] The present invention relates to Sigma-Delta A / D and D / A converter, be specifically related to a kind of when adopting multi-bit quantizer in Sigma-Delta A / D and D / A converter because of the non-linear error produced by capacitance mismatch full digital correction method. Background technique [0002] Since Sigma-Delta A / D and D / A converters have the characteristics of more digital circuits and less analog circuits, under the current trend of increasing integration of integrated circuit manufacturing processes, Sigma-Delta A / D and D / A Converters are developing toward high precision and high conversion rates, and are widely used in consumer, industrial control, communication and other fields. [0003] The structures of Sigma-Delta A / D and D / A converters are shown in Figure 1 and Figure 2 respectively. In order to improve the stability of the modulator and the signal-to-noise ratio (SNR) of the converter, multi-bit quantization is often used. However, ...

AI Technical Summary

Problems solved by technology

However, when using a multi-bit quantizer, it is necessary to use a multi-bit DAC (Digital-Analog Converter, digital-analog converter, referred to as a digital-to-analog converter). For a multi-bit DAC composed of switched capacitors, as shown in Figure 3, the quantization The output of the device is coded to control the opening and closing of the switched capacitor. Due to the manufacturing process, it is difficult to make each unit capacitor exactly the same size, which will cause nonlinear errors and a large amplitude within the signal bandwidth. Harmonics, thereby reducing the signal-to-noise ratio of the entire A / D, D / A converter

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