Structure and method for carrying out A/D converter with multiple sampling rates and high accuracy

Abstract

The structure is composed of the decimation filter and the FIR filter. In the decimation filter, the input high-speed data stream is processed with frequency degression procedure and is converted into low speed data stream, after being filtered off the input signal, it is rectified into the quantified noise of high frequency. The FIR filter processes the result of the decimation filter with frequency compensation of passing band to reach the better accuracy. On the other hand, the transition band is steeper, thus makes the greater attenuation of the frequency.

Description

Technical field [0001] The present invention relates to an architecture and implementation method for a multi-sampling rate high-precision analog-to-digital converter (ADC). Background technique [0002] Currently, in most analog-to-digital converter (ADC) applications, the digital circuit only uses a down-frequency filter (Decimation filter), and its sampling rate is fixed. At the same time, the transfer function through the frequency reduction filter (Decimation filter) is not flat in the passband, the attenuation is large, the gain is gradually decreasing in the frequency domain, and the same gain cannot be maintained in the required passband. The application environment is suitable; the finite impulse response filter (FIRflter) can just make up for the defect of the former transfer function in the spectrum, so that the transfer function changes very little in the passband, such as controlling ±0.1dB, which is very important in precision measurement (Metering) and high-l...

AI Technical Summary

Problems solved by technology

At the same time, the transfer function of the Decimation filter is not flat in the passband, the attenuation is large, and the gain gradually decreases in the frequency domain, and the same gain cannot be maintained in the required passband, which is not suitable for higher requirements. The application environment; the finite impulse response filter (FIRflter) can just make up for the defects of the former transfer function in the spectrum, so that the transfer function changes very little in the passband, such as controlled at ±0.1dB, which is in the precision measurement (Metering) and advanced audio (HIFI-audio) applications are required

However, the structure of the finite impulse response filter (FIR filter) is complex, and it is impossible to use the finite impulse response filter (FIR filter) alone to reduce the frequency of the high-frequency input signal multiple times.

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