Chapter 3
Adjustment
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National Instruments Corporation
3-27
•
actualData
—
&desiredFrequency
•
measuredData
—
¤tFrequency
b.
Set the VCXO with the new “best-guess” value (normal mode) by
calling the function
ni54xx_CalibrateVCXO
. Set the following
parameters:
•
sessionHandle
—The handle of the calibration session for the
device
•
type
—
NI54XX_SET_VCXO
c.
Measure the new frequency (
currentFrequency
).
If you have exited the loop, the VCXO is adjusted within the tolerance or as
close as possible.
You have completed adjusting the VCXO.
Calibrating the M-PAL Video Mode for NI 5431
To calibrate the M-PAL video mode for NI 5431 devices only, complete the
following steps:
1.
Enable the analog filter by calling the function
ni54xx_SetAnalogFilter
. Set the following parameters:
•
sessionHandle
—The handle of the calibration session for the
device
•
filterState
—
NI5XX_ENABLE
2.
Generate a full scale (10 V) sine wave at 1 MHz in M-PAL video mode
by calling
ni54xx_GenerateVideoWaveform
. Set the following
parameters:
•
sessionHandle
—The handle of the calibration session for the
device
•
waveType
—
NI54XX_SINE
•
amplitudeInVolts
—
10
•
frequencyInHz
—
1000000
•
videoMode
—
NI54XX_PAL_M
3.
Set the gain and offset by calling the function
ni54xx_SetAdjustedGainAndOffset
with 0 offset and
0 attenuation, in the unterminated case. Set the following parameters:
•
sessionHandle
—The handle of the calibration session for the
device
•
offsetInVolts
—
0