National Instruments PCI E Series Programmer's Manual

Chapter 2 Theory of Operation
PCI E Series RLPM 2-16
© National Instruments Corporation
Figure 2-12. Multirate Scanning of Two Channels with 3:1:1 Sampling Rate
Here, channel 0 is sampled three times, whereas channels 1 and 2 are
sampled once every three scans.
Figure 2-13. Multirate Scanning of Three Channels with 4:2:1 Sampling Rate
Multirate Scanning Using Ghost
If the ghost option in the configuration memory is set, that conversion
occurs but the data is not stored in the analog input FIFO. In other words,
a conversion is performed and the data is thrown away. By using this
option, multirate scanning with ratios such as x:y are possible, within the
limits imposed by the size of the configuration memory.
Figures 2-14 and 2-16 illustrate the advantages of using the ghost feature.
Figure 2-15 shows Example 3 timing, and Figure 2-16 shows the same
example using ghost.
Example 3: channel 1: channel 0 = 2:3 (without ghost).
START
STOP
Sampling Rates
Channel 0: Channel 1: Channel 2 = 3:1:1
CONVERT
0 0 01 2
START
STOP
CONVERT
0
000121
Sampling Rates
Channel 0: Channel 1: Channel 2 = 4:2:1

National Instruments PCI E Series Specifications

General

Brand	National Instruments
Model	PCI E Series
Category	I/O Systems
Language	English