E. Balestrieri

A state of the art on ADC error compensation methods

Analog-to-digital converters (ADCs) are critical components of signal processing systems. ADC errors can compromise the overall accuracy and the effectiveness of the whole system. This leads the researchers to direct an increasing attention to error correction topics. In the paper, some ADC error compensation methods are briefly introduced according to a classification criterion based on the main research trends.

ADC parameters and characteristics

Today, most of the signal processing performed in electronic systems is digital, and the performance of the analog-to-digital converters (ADCs) present at the borders of the digital domain become very important. The most recent applications in telecommunication, measurement, and consumer electronics call for ever-increasing ADC resolution and speed. The uncertainty of ADC performance strongly affects overall system accuracy. Both manufacturers and system integrators are intensely concerned with ADC performance.

ADC testing - Part 7 in a series of tutorials in Instrumentation and Measurements

A nalog-to-digital converters (ADCs) are tested for several reasons. Manufacturers need to measure the ADC’s performance so that they can guarantee to their users what performance to expect of the ADC (usually via a specification sheet) and to assure the quality of the ADCs they produce. Users need to measure the ADC’s performance relative to its specification as well as for its intended use. Both static and dynamic performance parameters may be assessed. It is important for those measuring ADC performance to communicate their findings clearly. To that end, the IEEE Instrumentation and Measurement Society’s Waveform Generation, Measurement, and Analysis Committee (TC-10) developed the IEEE Standard for Terminology and Test Methods for Analog-to-Digital Converters (IEEE Std 1241-2000) [1]. This standard presents a wide range of terms and test methods to serve as a common technical language among users and manufacturers. Since it would be prohibitively expensive for both manufacturers and users to perform all possible tests, only parameters critical to an application are generally assessed. Table 1 suggests parameters critical to common applications. These suggestions are intended to provide a starting point from which to select a set of parameters for a particular application. The following sections address general test setups, common test methods, and the assessment of uncertainty in measurements. The same tests are also performed on digital waveform recorders, but the test setups are different and are described in IEEE Std 1057-1994. See “ADC Versus Waveform Recorder—What’s the Difference?” for more information.

Experimental Comparison of Different Standards for Dynamic Characterization of ADCs

This paper reports the first results of an experimental comparison of the test procedures described in the IEC and IEEE standards for the measurement of the analog-digital converter (ADC) dynamic performance in the frequency domain. The comparison has been carried out by setting up the standard test benches and applying the standard test procedures for measuring the spurious free dynamic range (SFDR), total harmonic distortion (THD), signal-to-noise-and-distortion ratio (SINAD), signal-to-noise ratio (SNR), and effective number of bits (ENOBs) of the three actual ADCs. The achieved results show a good degree of harmonization, even if the procedures and formulas are different.

DAC Time-Domain Specifications Toward Standardization

This paper analyzes a set of digital-to-analog converter (DAC) time-domain specifications, including DAC settling time, rise time, fall time, and glitch energy. Some useful comments are provided to highlight ambiguity in the mostly used definitions, and new definitions are suggested whenever necessary.

Standard calibration procedures for automated non-invasive measurement of blood pressure

This paper focuses on the need for standardised calibration procedures for automated non-invasive measurement of blood pressure. A critical overview of the existing standards and protocols dealing with the calibration of these devices is provided highlighting the need for a univocal definition of their performance and accuracy, together with objective test methods. This is an expanded version of a paper presented at the 3rd IEEE International Workshop on Medical Measurements and Applications, 9 10 May 2008, Ottawa, ON, Canada.

Automated Non-Invasive Measurement of Blood Pressure: Standardization of Calibration Procedures

In this paper the need for standardized calibration procedures for automated non-invasive measurement of blood pressure is highlighted. In particular, the IEC 60601-2-30, the EN 1060 and the ANSI/AAMISP-10 are described. A critical overview of the existing standards and protocols dealing with the calibration of these devices is provided focusing on the device specifications and the test methods, including the most used clinical protocols like the British Hypertension Society one. The analysis of the reported references put in evidence the need for a clear and unique set of definitions and objective methods for calibrating blood pressure measuring devices. The IEEE PI 721 project for a new standard on Objective Measurement of Systemic Arterial Blood Pressure in Humans started recently with such purposes.

Estimating the Uncertainty in the Frequency Domain Characterization of Digitizing Waveform Recorders

New propagation formulas for the uncertainty evaluation for the characterization of digitizing waveform recorders are proposed in this paper. The frequency domain figures of merit, as defined in IEEE Std. 1057, have been considered to present useful addenda to the standard. The proposed formulas have been validated on simulated and actual signals.

Towards accurate NIBP simulators: Manufacturers' and researchers' contributions

Hypertension, the most commonly managed problem in general practice, in its early stages can be diagnosed only by measurement of blood pressure. The prevalent automated method for this purpose is based on the oscillometric principle. The evaluation of the measurement accuracy for oscillometric automated devices involves costly and time consuming population studies, often providing contradictory results. The NIBP simulators, that regenerate oscillometric waveforms, promise an alternative to clinical trials. In the paper a comparison among the most used commercial NIBP simulators is reported, as well as the last research proposals useful to the development of IEEE P1721 project for a new Standard on Objective Measurement of Systemic Arterial Blood Pressure in Humans are analyzed.

ADC Standard Harmonization: Comparison of Test Methods

The paper describes an experimental investigation for the harmonization of the measures of the ADC dynamic performance in the frequency domain, according to the Standards in the field. The comparison results, involving spurious free dynamic range (SFDR), total harmonic distortion (THD), signal to noise and distortion ratio (SINAD), signal to noise ratio (SNR) and effective number of bits (ENOB), show a good degree of similitude among the results provided using procedures and formulas from different standards of IEEE and IEC.