©
National Instruments Corporation
6-1
PCI-4451/4452/4453/4454 User Manual
6
Theory of Analog Operation
This chapter contains a functional overview and explains the operation
of each analog functional unit making up the PCI-445X.
Functional Overview
♦
PCI-4451/4452
See Figure 3-2,
PCI-4451/4452 Analog Function Block Diagram
, for a
general block diagram of the PCI-4451/4452 analog functions.
♦
PCI-4453/4454
See Figure 3-3,
PCI-4453/4454 Analog Function Block Diagram
, for a
general block diagram of the PCI-4453/4454 analog functions.
Analog Input Circuitry
♦
PCI-4451/4452
The PCI-4451 has two identical analog input channels. The PCI-4452 has
four identical analog input channels. An analog input channel is illustrated
in Figure 4-4,
Analog Input Stage of the PCI-4451/4452
.
These input channels have 16-bit resolution and are simultaneously
sampled at software-programmable rates from 5 to 204.8 kS/s in 190.7 µS/s
increments. This flexibility in sample rates makes the device well suited for
a wide variety of applications, including audio and vibration analysis.
The differential analog inputs have AC/DC coupling. You can use the
programmable gain amplifier stage on the inputs to select gains from
–20 to 60 dB in 10 dB increments. The input stage has differential
connections, allowing quiet measurement of either single-ended or
differential signals.
