Analyzing the linearity of ramp waveforms generated by means of AWG

Highly linear ramp waveforms are important in a variety of industrial processes, control systems, and test and measurement applications. The generation of ramp waveforms can be accomplished in several ways by means of both dedicated circuits and arbitrary waveform generators; the latter ones also grant the widest configurability of the output waveform both in terms of time and amplitude parameters. But, the waveforms generated by means of arbitrary waveform generators are characterized by piecewise time domain evolution. The underneath piecewise frame always implies a reduced conformity of the generated waveform to the intended one, even if the waveform is smoothed by means of a low-pass filter integrated in the generation chain. Conformity analyses can be carried out both in time and frequency domain, and their results expressed either by means of an error waveform or by pointing out the undesired spectral contributions. Typically, the insights allowed by the spectral analysis greatly help in both understanding the causes of poor conformity, and docum enting the precision of the output waveform. Hereinafter, first a general explanation of the mechanisms that originate the distortion contributions and reduce the conformity of a piecewise waveform to the intended one is given. Then, the attention is focused on ramp waveforms generated by means of arbitrary waveform generators and a thorough analysis of their conformity to an ideal ramp is carried out.