Measurement Computing Data Translation DT9857, User Manual

Page: 142 / 192

Appendix A
142
Analog Input Specifications
Table 24 lists the specifications for the analog input subsystem on the DT9857 and DT9857E
modules. Unless otherwise noted, specifications are typical at 25
°
C
.
Table 24: Analog Input Subsystem Specifications
Feature DT9857 Specifications DT9857E Specifications
Number of analog input channels
DT9857-08:
DT9857-16: 8, single-ended
16, single-ended 8, single-ended
16, single-ended
Resolution 24 bits 24 bits
Ranges and gains
Gain of 1:
Gain of 10: ±10 V
±1 V ±10 V
±1 V
A/D type Delta Sigma Delta Sigma
Data encoding Offset binary Offset binary
Maximum sample rate 105.469 kS/s 105.469 kS/s
Minimum sample rate 195.3125 S/s 195.3125 S/s
ADC master clock range
Sampling frequency
< 52.734 kHz:
52.734 kHz to 105.469 kHz:
100 kHz to 27 MHz
512 x sample frequency
256 x sample frequency
100 kHz to 27 MHz
512 x sample frequency
256 x sample frequency
Group delay 39/sample rate, in seconds 39/sample rate, in seconds
ADC Delta Sigma filter
a
Passband, –3 dB:
Passband ripple, ±0.005 dB:
Stopband, –100 dB: 0.49 x sample frequency, Hz
0.453 x sample frequency, Hz
0.547 x sample frequency, Hz 0.49 x sample frequency, Hz
0.453 x sample frequency, Hz
0.547 x sample frequency, Hz
Analog filter
a
Low pass cutoff, –3 dB:
High pass cutoff, –3 dB (AC coupling): 400 kHz
0.5 Hz 400 kHz
0.5 Hz
Channel-to-channel crosstalk
b
Input Signal =10 kHz:
> –110 dB with 50
Ω
termination
> –105 dB with 1 k
Ω
termination
> – 110 dB with 50
Ω
termination
> –105 dB with 1 k
Ω
termination
Input impedance 1 M
Ω
|| 20 pF
c
1 M
Ω
|| 20 pF
c
Coupling AC/DC (software-selectable per
channel) AC/DC (software-selectable per
channel)
IEPE current source 4 mA ±0.5% 4 mA ±0.5%
IEPE compliance voltage 24 V 24 V
IEPE current source noise
DC to 1 kHz 5 nARMS 5 nARMS