National Instruments PCI-6281, User Manual

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5-1
5
Analog Output
Many M Series devices have analog output functionality. M Series devices that support analog
output have either two or four AO channels that are controlled by a single clock and are capable
of waveform generation. Refer to the specifications document for your device for information
about the capabilities of your device.
Figure 5-1 shows the analog output circuitry of M Series devices.
Figure 5-1. M Series Analog Output Circuitry
The main blocks featured in the M Series analog output circuitry are as follows:
•
DACs
—Digital-to-analog converters (DACs) convert digital codes to analog voltages.
•
AO FIFO
—The AO FIFO enables analog output waveform generation. It is a
first-in-first-out (FIFO) memory buffer between the computer and the DACs. It allows you
to download the points of a waveform to your M Series device without host computer
interaction.
•
AO Sample Clock
—The AO Sample Clock signal reads a sample from the DAC FIFO and
generates the AO voltage.
•
AO Offset and AO Reference Selection
—AO offset and AO reference selection signals
allow you to change the range of the analog outputs.
AO 2
AO 3
DAC2
DAC 3
AO D a t a AO FIFO
AO Sa mple Clock
AO Off s et S elect
AO Reference S elect
AO 0
AO 1
DAC0
DAC1