HIGH-SPEED DEVICE FOR ANALOG-DIGITAL CONVERSION OF SIGNALS WITH DIGITAL CORRECTION OF TIME UNCERTAINTY ERRORS

Abstract

The paper proposes a method of increasing the resolution of a high-speed analog-to-digital signal conversion device based on digital error correction of the time uncertainty of the output signal. To increase the speed of such devices, the principle of structural parallelization of analog-to-digital signal conversion channels with subsequent expansion in time is used. This approach involves the use of the multiphase sampling mode of analog-to-digital converters of the reading type (ADC) connected in parallel.

In the analog-to-digital conversion device built on the basis of read-type ADC connected in parallel, the discretization of the input signal is accompanied by the deviation of the actual moments of the formation of the output digital codes from their nominal location in the time domain. At the same time, there is a temporal uncertainty of the output digital codes of the ADC. Errors in the time uncertainty of the output signal of the ADC lead to a decrease in the resolution of the analog-to-digital conversion device.

It is proved that the temporal uncertainty of the output signal of the converter manifests itself in the form of parasitic components in the spectrum of the output signal. Compensation of time uncertainty errors is performed using digital filtering of the output signals of analog-to-digital converters of the reading type, on the basis of which a high-speed analog-to-digital conversion device is built.

An analysis of the effectiveness of the proposed method of error correction in a high-speed analog-to-digital signal conversion device was performed. One of the most  general parameters of an ADC is the effective number of bits. This parameter defines the resolution of the transducer in the specified dynamic mode. The analysis of the effectiveness of the proposed method confirmed that thanks to the developed method, it is possible to increase the resolution of a 12-bit high-speed analog-digital conversion device by 5-7 bits in the studied frequency band.