© National Instruments Corporation 17 NI PXI-5600 Calibration Procedure
• numberOf Steps = 21
• index = current index of the loop (first iteration is 0)
The return value is the frequency of the current loop iteration.
b. Set the signal generator frequency to the frequency value returned
(in Hz) by
niTuner_CalGetStepFrequency in step 11a.
c. Wait 50 ms for the signal generator to settle.
d. Acquire channels A and B on the power meter. Send them as
inputs to
niTuner_CalAdjustExternalCalibration with
the following parameters:
• IFOutputPower = channel A power (in dBm)
• RFInputPower = channel B power (in dBm)
• calibrationProcedure =
0 (temperature correction
coefficient)
12. Repeat step 11 until the done value returned by
niTuner_CalAdjustExternalCalibration on the last iteration
is
1 (or TRUE).
13. Call
niTuner_CalCloseExternalCalibration to end the
calibration session. Set action to
0 to commit your changes, or to 1 if
you want to cancel without saving.
Adjusting the Internal Reference Frequency
Caution You must allow a warm-up time of at least 20 minutes before you begin the
remaining adjustment procedures.
To adjust the internal reference frequency accuracy on the NI PXI-5600,
write a program that includes the following steps:
1. Call
niTuner_CalInitializeExternalCalibration to open
the calibration session.
2. Call
niTuner_CalSetAttenuation with the following parameters:
• refLevel =
0
• mixLevel = –30
3. Call niTuner_CalSetClockSource and set the clock source to
internal.
4. Call
niTuner_CalAdjustInternalReferenceFrequency with
the following inputs:
• frequency =
0
• accuracy = 0
5. Lock the spectrum analyzer to the 10 MHz OUT square wave output
of the rubidium source.
