Analog Output is primarily used to provide excitation sources for data acquisition systems, and it can be thought of as a signal generator. The core component of Analog Output is the Digital-to-Analog Converter (DAC), and certain technical specifications of the DAC determine the characteristics of the analog signals that can be output. When considering relevant parameters for analog output in a Data acquisition device (DAQ) system, the main focus lies on the number of channels, sampling rate, resolution, and output voltage range.
Number of Channels
The number of channels for analog output refers to the number of channels available for analog signal output.
Sampling Rate
The sampling rate determines the number of digital-to-analog conversions per second and is usually measured in Sa/s (samples per second). A higher sampling rate allows for more data to be output in the same amount of time, thereby better reproducing the signal. The following set of graphs shows the time-domain waveform of a sine wave with a frequency of 1 kHz output at different sampling rates.
5kSa/s Sampling Rate
10kSa/s Sampling Rate
20kSa/s Sampling Rate
50kSa/s Sampling Rate
Resolution
The resolution of the digital-to-analog converter refers to the number of bits used to represent the analog signal. A higher resolution means that the signal range is divided into more segments, allowing for a smaller minimum voltage change that can be output.
For example, with a 16-bit analog output and a range of ±5V, the voltage resolution would be (5 * 2) / 65536 (2^16) = 15.27 μV.
The following set of graphs shows the time-domain waveform of a sine wave in the range of 0 to 1 sampled at different resolutions.
2-bit Resolution
3-bit Resolution
4-bit Resolution
5-bit Resolution
Range
The range represents the minimum and maximum voltage values that the digital-to-analog converter can quantify.
