National Instruments AT-MIO-16X Analog Data Acquisition Rates

Appendix A Specifications

AT-MIO-16X User Manual A-4

National Instruments Corporation

Relative accuracy is a measure of the (non)linearity of an analog

system. It indicates the maximum deviation of the averaged

analog-input-to-digital-output transfer curve from an endpoint-fit

straight line. If the analog circuitry has been calibrated perfectly, then

the endpoint-fit straight line is the ideal transfer function, and the

relative accuracy specification indicates the farthest deviation from the

ideal that the system permits.

Differential nonlineari ty (DNL) is a measure of deviation of code

widths from their theoretical value of 1 LSB. The width of a given code

is the size of the range of analog values that can be input to produce that

code, ideally 1 LSB. A specification of ±1 LSB differential nonlinearity

ensures that no code has a width of 0 LSBs (that is, no missing codes)

and that no code width exceeds 2 LSBs. DNL is measured using

histograms.

System noise is the amount of noise (in LSB rms) in the ADC data when

there is no signal present at the input of the board. This figure includes

the quantization noise of the ADC.

Analog Data Acquisition Rates

The maximum single-channel data acquisition rate of the AT-MIO-16X

is 100 ksamples/sec (10-µsec sample period). The AT-MIO-16X m ay

run as fast as 111 ksamples/sec (9-µsec sample period), but with

unspecified accuracy.

Table A-2. Equivalent Gain Errors in 16-Bit Systems

Range

Error at Full-Scale Gain Error

LSB % of FSR % of Gain PPM of Gain

0 to 10 V 1 0.001526% 0.001526% 15.26 ppm

–10 to 10 V 1 0.001526% 0.003052% 30.52 ppm