Chapter 4
Programming
NI PXIe-5450 User Manual
4-24
ni.com
Configuring an External Sample Clock
Some NI signal generators can accept an external clock to directly drive the
Sample clock. When using an external Sample clock, the frequency
stability and accuracy of the Sample clock is determined by the external
Sample clock provided.
LabVIEW Example
1.
Call the niFgen Configure Sample Clock Source VI with the
Source
set to an external location.
Perform the following step if your application is configured for Arbitrary
Waveform, Arbitrary Sequence, or Script output mode:
2.
Call the niFgen Set Sample Rate VI with the
Sample Rate
set to the
frequency of the external device you are using as a clock source.
C Example
1.
Call the
niFgen_ConfigureSampleClockSource
function with
the
sampleClockSource
parameter set to an external location.
Perform the following step if your application is configured for Arbitrary
Waveform, Arbitrary Sequence, or Script output mode:
2.
Call the
niFgen_ConfigureSampleRate
function with the
sampleRate
parameter set to the frequency of the external device you
are using as a clock source.
Configuring a Reference Clock
You can specify the source for the Reference clock that will be used in a
phase-locked loop to tune the Sample clock timebase to the frequency
stability of the Reference clock.
LabVIEW Example
Call the niFgen Configure Reference Clock VI with
Source
set to the
Reference clock source. For example, set
Source
to “ClkIn” to obtain the
Reference clock signal from the Clk In front panel connector. Set
Reference Clock Frequency
to the frequency of the Reference clock.
