ADLINK PCIe-9529 - Manual (Page 29)

Operations 19
PCIe-9529
3.2.2 Input Range and Data Format
When using an A/D converter, properties of the signal to be mea-
sured should be considered prior to selecting channel and signal
connection to the module. A/D acquisition is initiated by a trigger
source, which must be predetermined. Data acquisition com-
mences once the trigger condition is established. Following com-
pletion of A/D conversion, A/D data is buffered in a Data FIFO,
and can then be transferred to PC memory for further processing.
Transfer characteristics of the two input ranges of the PCIe-9529
are as follows. Data format of the PCIe-9529 is 2’s complement.
.
Table 3-1: Input Range and Data Format
Table 3-2: Input Range Midscale Values
3.2.3 ADC and Analog Input Filter
ADC (Analog-to-Digital Converter)
The PCIe-9529 provides sigma-delta analog-to-digital converters,
suitable for vibration, audio, and acoustic measurement. Analog
side of the sigma-delta ADC is 1-bit, and the digital side performs
oversampling, noise shaping and digital filtering. For example, if a
desired sampling rate is 108kS/s, each ADC samples input signals
Description
Full-scale
range
Least
significant
bit
FSR-1LSB -FSR
Bipolar Analog
Input
±10 V 1.19 μV 9.99999881 V -10 V
±1V 0.119 μV 0.999999881V -1 V
Digital Code N/A N/A 7FFFFF 800000
Description Midscale +1LSB Midscale Midscale –1LSB
Bipolar Analog
Input 1.19 μV 0 V -1.19 μV
0.119 μV 0 V -0.119 μV
Digital Code 000001 000000 -FFFFFF