Can I perform Octave analysis without SV toolset

[Alv]

I'm getting eronous data from the SVT octave vi from 10-100Hz (roll-off). I want to compare data without using the octave vi's. Can this be done?

[JFT']

Hi Alv,

Could you be more specific, i mean,
What you are trying to do, it's an analog input task using... what kind of daq hardware?, What kind of comparison do you need to do?
And the version of your SW(SVT and LV) is ...?.

JFT

[Alv]

I'm looking at analog input data (pre-recorded data from transducer). I have PXI w/NI4472 DAQ cards and displaying the data in 1/3 octave. I have LV 7.1 w/SVT. I was getting eronous data at low frequency (10-100Hz) when running calibration signal. After talking w/NI it was determined my # of samples weren't high enough to capture data in the lower 1/3 octave center band frequencies. Once I increased the # S, the accuracy of the magnatude increased. I still have one concern, when displaying the data (cal signal) the surrounding 1/3 octave bands are unusually high (like there is white noise present. I quantified this by using a CSI spectrum analyzer in para. Although when analyzing the data w/higher #S the levels are very close to pre-recorded data. So, I'm satis
fied w/my results for now. I'm still interested in doing additional octave analysis.

[JFT']

Alv,
I assume you set coupling according with your task... maybe you need a DC coupling for this specific frequency band. Also since LV 7.1, with NiDaq(>7.2) allows to use MX driver(DaqMx) with the 4472 HW. In my personal experience this driver has better performance that traditional (NiDaq), you could try using it. Normally, before using the mx driver you have to reset the device in MAX.
Hope this help,

JFT