Using LabView to collect Voltage vs. Frequency with DAQ

[benfitzgerald]

Hello I'm currently working on a project that involves measuring the output of a bandpass filter versus frequency.  I have the filter circuit (just a HPF and LPF) connected to the DAQ and into LabView.  The input to the circuit is a frequency sweep driven by the output of a computer soundcard from 60Hz-10kHz.  Our cutoff frequencies are around 400Hz and 1600Hz. 

Basically I am trying to have LabView collect voltage and frequency information simultaneously so that I can make a log plot on excel.  I've tried using the waveform graph but it only shows voltage vs. time and analyzing this data in excel is  nightmare.  Anything would help, thanks.

[Stefo]

Hello benfitzgerald,

if you need to plot amplitude vs frequence to display characteristic of the filter, you will have to use XY Graph. Regular graph or chart, as you have noticed will allow you to plot data on Y axis with equal distances on x axes.

Please see Types of Graphs and Charts. In LabVIEW, try to search for examples (Help -> Find Examples) for XY graph. As datatype, it uses cluster of 2 elements (1D arrays) - X and Y data.

regards,

stefo