USB-6009 analog sinewave input problem

[Joebui]

Hello,

I'm a newbie to Labview. I'm using Labview 2009 and USB-6009. i tried to use USB-6009 to display sinewave input signal from function generator. First, the sinewave look perfect at the frequency 1KHz but when i changed to frequency to 10KHz, the sinewave turned into triangle wave. When i test input signal, i set the sampling rate is 48KHz and terminal configuration is RSE. Is there any problem with USB-6009?

[Dennis_Knutson · Accepted solution]

You really need to spend some time studying sampling and the Nyquist theorem  - not LabVIEW. To accurately reproduce the sine wave shape, you would need to go to a sample rate 10 times higher than your input frequency. With the 6009, that means limiting the input to less than 5kHz.