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Chapter 3
Theory of Operation
© National Instruments Corporation
3-3
SCXI-1100 User Manual
The major components of the SCXI-1100 are as follows:
•
The SCXIbus connector
•
The digital interface
•
The digital control circuitry
•
The timing and analog circuitry
The SCXI-1100 consists of eight CMOS four-to-one dual multiplexers for a total of 32
differential channels and a PGIA with gains of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1,000, and
2,000. The SCXI-1100 also has a digital section for automatic control of channel scanning, gain
selection, amplifier output selection, MUXCOUNTER clock selection, calibration, and auto-
zeroing.
The theory of operation for each of these components is explained in the remainder of this
chapter.
SCXIbus Connector
Figure 3-3 shows the pinout of the SCXIbus connector.