National Instruments NI USB-621x manual 45

Chapter 4 Analog Input

ai/SampleClock
ai/ConvertClock
			0 1 2 3		0 1 2 3
Channel Measured	0 1 2 3
		Sample #1		Sample #2		Sample #3

•Sample Clock Too Fast for Convert Clock

•Sample Clock Pulses are Gated Off

Figure 4-10.ai/SampleClock Too Fast

ai/SampleClock
ai/ConvertClock
	0 1 2 3		0 1 2 3		0 1 2 3
Channel Measured
		Sample #1		Sample #2		Sample #3

•Convert Clock Too Fast for Sample Clock

•Convert Clock Pulses are Gated Off

Figure 4-11.ai/ConvertClock Too Fast

ai/SampleClock
ai/ConvertClock
	0	1	2	3	0	1	2	3	0
Channel Measured
		Sample #1				Sample #2				Sample #3

•Improperly Matched Sample Clock and Convert Clock

•Leads to Aperiodic Sampling

Figure 4-12.ai/SampleClock and ai/ConvertClock Improperly Matched

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