ADLINK PXI-2022 - Manual (Page 14)

6 Introduction
Timebase System
Auto Calibration
Timebase Specifications
Model Name PXI-2020/2022
Timebase Source
(1) Internal: onboard 80MHz oscillator
(2) External from hardware IO
Sampling Rate Range
Timebase divided by 32-bit counter.
TIMEBASE(80MHz) divider to the achieve
equivalent sampling rate of DAQ. The equa-
tion is:
Sampling rate = TIMEBASE / ScanIntrv
The value of TIMEBASE depends on the
card type. Take PXI-2022 (250KS/s) as an
example, the ScanIntrv = 320 results in
250KS/s and ScanIntrv = 640 results in
125KS/s, and so on.
Internal Timebase Accuracy <±25ppm (typical)
External Timebase Clock
Sources (External from hardware IO)
(refer to section 4.3 for details)
(1) PXI_10M
(2) AFI [0..7]
(3) PXI Trigger BUS[0]
(4) PXI Star Trigger
(5) SMB_CLK
Dedicate External Clock Input From IO Connector
Clock Type Digital TTL
Input Frequency Range 1MHz ~ 20MHz
Input Coupling DC
Input Compatibility Input 3.3V or 5V TTL
Table 1-5: Timebase System
Auto Calibration Specifications
Model Name PXI-2020/2022
Onboard reference +5.000 V
Recommended warm-up time: 15 minutes
Temperature drift ±3 ppm°C (ADR02 5V Reference Chip)
Stability
50 ppm/1000hrs
(ADR02 5V Reference Chip)
Table 1-6: Auto Calibration