Chapter 4

Analog Input

 

 

 

 

 

Analog Comparison Event

 

 

ai/SampleClock

 

 

 

 

 

 

 

20 MHz Timebase

 

 

 

 

Ctr n Internal Output

 

 

 

 

 

 

 

 

 

 

 

ai/SampleClock

SW Pulse

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Timebase

 

 

 

 

 

 

 

 

Programmable

 

 

 

 

 

 

 

 

 

Clock

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Divider

 

 

 

100 kHz Timebase

 

 

 

 

Ctr n Internal Output

 

ai/ConvertClock

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ai/ConvertClock

 

 

 

 

 

 

 

 

 

Timebase

Programmable

 

 

 

 

 

 

 

 

 

Clock

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Divider

 

 

 

Figure 4-4.Analog Input Timing Options

M Series devices use ai/SampleClock and ai/ConvertClock to perform interval sampling. As Figure 4-5shows, ai/SampleClock controls the sample period, which is determined by the following equation:

1/Sample Period = Sample Rate

Channel 0

Channel 1

Convert Period

Sample Period

Figure 4-5.Interval Sampling

ai/ConvertClock controls the Convert Period, which is determined by the following equation:

1/Convert Period = Convert Rate