PCIe-24DSI32
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General Standards Corporation Ph:(256)880-8787 FAX:(256)880-8788 Email: [email protected]
4-1
SECTION 4.0
PRINCIPLES OF OPERATION
4.1 General Description
The PCIe-24DSI32 board contains sixteen dual delta-sigma 24-Bit A/D converters and all
supporting functions necessary for adding analog I/O capability to a PCIe expansion system. A
PCIe interface adapter (Figure 4.1) provides the interface between the controlling PCIe bus and
an internal local controller through a 32-bit local bus. The local controller performs all internal
configuration and data manipulation functions, including autocalibration.
PCI
Conn
I/O
Conn
Analog
Inputs
(32 Diff)
Input
Configuration
Switches
PCI Interface Adapter
Voltage
Reference
V-Test
Out
Sample-Rate
Generator(s)
Local
Controller
Input
Data
24-Bit ADC
Input
Control
Image
Filters
Diff Amp
Range
Control
Power
Conditioning
+5VDC
(One of 32 Identical Channels)
32-Bit Local Bus
Figure 4.1. Functional Block Diagram
Input configuration switches allow the controller to select any of several signal sources as
inputs to the ADC's. This feature is used to establish the internal connections necessary during
autocalibration, and also permits verification from the PCIe bus of the integrity of all analog
input channels. All channels are calibrated against a single precision voltage reference. The
offset and gain calibration of each input channel is adjusted with correction values that are
determined during autocalibration.
