An improved method of generating analog waveforms from digital data

Abstract

As normally used, the digital-to-analog converter generates a series of constant amplitude signals that, taken together, approximate the desired analog equivalent of the initial digital signal. Hence, many samples are required to generate a reasonably smooth approximation. Even so, it is usually necessary to filter the resulting approximation to remove the sharp corners of the constant amplitude signals and blend them together. This requirement is particularly troublesome in the case of generating very low frequency analog signals, e.g., a 1 Hz sine wave. In this article we propose an inexpensive improvement in the commercial digital-to-analog converter cards. This improvement results in a waveform with much better quality than that produced by the usual methods.