Métodos de testes de conversores analógico para informação baseados no padrão IEEE 1241.

Abstract

Integrated circuits testing is an important stage in the manufacture and fundamental in the commercialization of these components, because in this stage are evaluated which circuits have defects and which are able to be commercialized. In mixed integrated circuits, such as analog-digital converters (ADC) that interface analog and digital parts of electronic systems, the test is performed by measuring parameters such as linearity, noise, among others. For ADC testing, there is the IEEE 1241 standard that establishes test methods and their procedures for evaluating static and dynamic parameters of ADC. One such method is the sine wave fit method. However, there is a new type of converter, Analog-to-Information Converter (AIC), which does not yet have a defined test pattern. The AIC implements the Compressive Sampling Theory in practical terms and provides a digitized and compressed output (y) corresponding directly to the analog input signal (x). A reconstruction algorithm is needed to obtain a reconstructed signal xˆ that computes x from y. This algorithm is generally not part of the AIC itself and may even be distant from the AIC interconnected by a communication channel to it. In scientific papers focusing on AIC testing, in general, the reconstructed signal xˆ is evaluated to test the AIC itself and as a consequence, the performance of the reconstruction algorithm may affect the result of the AIC test. The reconstruction algorithms implement the solution of an optimization problem and are quite sensitive to the input parameters, so it is not interesting that the test result depends on these algorithms. Few papers propose test methods that consider only the direct output of the AIC (y). However, they take into account a single test signal (the sine), which is a reference signal as described in the IEEE 1241 standard for ADC testing. In this thesis, two new test methods for AIC are proposed, in which only the AIC outputs, that is, the compressed outputs y, are taken into account. In the first one, multi-tones (multi-sines) are applied and, in the second, an adaptation of the sine wave fit method of four parameters, also recommended by the IEEE Standard 1241, was developed. Experimental and simulation results were obtained for two architectures of different AICs (Random Demodulator - RD and Random Modulation Pre-Integrator - RMPI) and the Signal to Noise and Distortion Ratio (SINAD) of both were measured directly from the AIC output confirming the functionality of the proposed AIC test methods.