SBAA051A January 1994 – April 2015 MSC1210Y2 , MSC1210Y3 , MSC1210Y4 , MSC1210Y5
4 System Throughput Accuracy
The most common method used to describe data acquisition and conversion system accuracy is to compute the root-sum squared (RSS) errors of the system components. The RSS error is a statistical value which is equivalent to the standard deviation (1σ), and represents the square root of the sum of the squares of the peak errors of each system component, including ADC quantization error:
Equation 3. 
- εMUX = analog multiplexer error
- εAMP = input amplifier error
- εSH = sample/hold error
- εADC = A/D converter error
where
The source irnpedance, data bandwidth, A/D converter resolution and system throughput rate affect these error calculations. To simplify, errors can be calculated by assuming the following:
- Aperture error is negligible - i.e., less than 1/10LSB.
- Source impedance is less than 1000 Ω.
- Signal range is ±10 volts.
- Throughput rate is equal to or less than the maximum shown in Table 3.
Table 3. System Error Contribution and RSS Error vs Resolution for Burr-Brown Model857KG Modular Data Acquisition System
| Error Source | Resolutions | |||
|---|---|---|---|---|
| 8 Bits | 10 Bits | 12 Bits | ||
| MUX Error | 0.0025% | 0.0025% | 0.0025% | |
| AMP Error | 0.01% | 0.01% | 0.01% | |
| S/H Error | 0.01% | 0.01% | 0.01% | |
| ADC Errors | Analog | 0.02% | 0.05% | 0.012% |
| Quantizing | 0.02% | 0.05% | 0.012% | |
| RSS Error | 0.283% | 0.072% | 0.022% | |