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The electronics involved in producing an accurate analog signal from the discrete data are similar to those used for generating the digital signal. These devices are [[digital-to-analog converter]]s (DACs). They produce a [[voltage]] or [[Electric current|current]] (depending on type) that represents the value presented on their digital inputs. This output would then generally be filtered and amplified for use.
To recover the original signal from the sampled data, a ''demodulator'' can apply the procedure of modulation in reverse. After each sampling period, the demodulator reads the next value and transitions the output signal to the new value. As a result of these transitions, the signal retains a significant amount of high-frequency energy due to imaging effects. To remove these undesirable frequencies, the demodulator passes the signal through a [[reconstruction filter]] that suppresses energy outside the expected frequency range (greater than the [[Nyquist frequency]] <math>f_s / 2 </math>).<ref group=note>Some systems use [[digital filter]]ing to remove some of the aliasing, converting the signal from digital to analog at a higher sample rate such that the analog [[anti-aliasing filter]] is much simpler. In some systems, no explicit filtering is done at all; as it
==Standard sampling precision and rates==
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