How can I look at the frequency spectrum of a portion of my data

Altair Forum User

Submitted by Joe on Wed, 10/26/2011 - 18:52 

 

Hi,

How can I look at the frequency spectrum of a portion of my data, say from 15 to 60- seconds rather than the full run of 0 to 60 seconds?

Thanks,

Joe

Altair Forum User

Submitted by Anders89 on Wed, 10/26/2011 - 19:11.

Good question Joe. There are a couple ways to skin this cat:

• The easiest way is to use a plot block, right click to configure, check Frequency Domain and Log Y, then select Axis tab, under Retrace Options set Start Time: to 15,End Time: to 60, and Interval: to 45.
• Another way is to use a triggered plot block: right click to configure, check Frequency Domain and Log Y and External Trigger. Then use a > block to compare a ramp to 15 and connect it to the trigger pin on the plot.
• Another way is to use a triggered buffer block and activate the trigger during the interval you want to capture. Then use the PSD (Power Spectral Density) block into a plot.