DA converters (D/A), digital-to-analog converters or digital-to-analog converters (DAU) are electronic circuits for converting a digitally coded quantity into an analog current or voltage waveform. The ideal DA converter generates the analog output voltage from the binary
input code, with a linear relationship between the two quantities.
The structure of digital-to-analog convertersThe entire conversion of a digital word into an analog signal takes place in several stages. First, the digital word is converted into individual analog voltage values in the actual DA converter. R-2R converters, pulse width modulation (PWM) converters or others are used for this conversion. The voltage at the output has a staircase shape. In the following stage, the stair-stepped signal is smoothed. This can be done by a sample and hold (S/H) circuit or with filtersharmonics
, as well as the frequencies that are present around thesampling rate
Important parameters of DA convertersparameters of
D/A converters include accuracy, which depends on the data word length of the digital input signal, conversion speed
andconversion time, and noise
marginand distortion. As with the AD converter, the signal-to-noise ratio of the D/A converter depends on the word length of the digital word, while the distortion factor depends on the converter linearity. The resolution of DA converters on the market is between 8 bits and 24 bits, in some cases
even 32 bits can be achieved. DA converters are used in audio and video technology.
For example, in CD and DVD drives, in MP3 players, mobile phones, telephones and smartphones.