National Instruments PXIe-5622, Процедура калибровки

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© National Instruments Corporation 45 NI 5622 Calibration Procedure
10. This step varies depending on the programming language used.
(LabVIEW) Compute the averaged power spectral density in V
rms
2
/Hz using
the FFT Power Spectral Density for 1 Chan VI.
(C/C++) Calculate the power spectral density on the array of data from
step 9.
11. Repeat steps 8 through 10 ten times to obtain an averaged power
spectral density.
12. Compute the average noise density from the averaged power spectral
density data using the following formula:
where
df = frequency resolution of the spectrum, in Hz
x = average power spectral density data, in V
rms
2
/Hz
Compare the result to the Published Specifications for the current
iteration listed in Table 8. If the result is within the selected test limit,
the device has passed this portion of the verification.
13. Repeat steps 4 through 12 for each iteration in Table 8.
LabVIEW VI Input Parameters
Set the following parameters:
restart averaging (F) : TRUE for iteration 1;
FALSE for iterations 2 through 10
window : Rectangle
dB On (F) : FALSE
averaging parameters»averaging mode :
RMS averaging
averaging parameters»weighting mode :
Linear
averaging parameters»number of
averages
:
10
average noise density 10 log
10
×
x
k
df
×
k 1
=
n

n
------------------------------
 
 
 
 
 
 
2
20 ×
df
--------------------------------------------------
 
 
 
 
 
 
 
 
 
=