Alternative method of A/D conversion quality verification

Well known methods for testing ADC dynamic quality (FFT Test, best sinusoidal curve fit method, histogram test) require a low-distortion generator and it can be a problem testing high-resolution and middle-resolution high-speed ADCs. The paper describes a new alternative method-spectrum correction test. It is based on the FFT test, but the distortion of a testing signal is corrected. The basic idea is the fact that the Fourier transform is a linear operation. Therefore it is possible to recognise spectral lines, which belong to the generator used and the lines of the ADC. The spectrum measured on the ADC's output can be corrected for the known spectrum of the generator. A PC simulation was executed to investigate if this method could be used. Then the system for evaluation of the test was designed and realised. The first experience and achieved results are also published in this paper.