Fast Fourier Transform (FFT) II (ID=7017)

This Windaq add-on is the second generation of Windaq Add-on FFT based on a more powerful commercial FFT module. It provides real-time FFT power spectrum for DATAQ's WinDaq  acquisition software, with multiple FFT sizes and higher resolution (see below)

 

    

Features

1. Multiple FFT sizes: 1024, 2048, 4096,  8192, 16384 and 32768
   • Due to Windaq's memory allocation approach, the following rule should be observed if you wish to use this add-on. Please make sure you upgrade to the latest DATAQ ActiveX. WinDaq Activex had a glitch that affects certain configuration of the add-ons and it was fixed recently.
     • For FFT size of 1024, up to 58 channels can be enabled in Windaq
     • For FFT size of 2048, up to 29 channels can be enabled in Windaq
     • For FFT size of 4096, up to 15 channels can be enabled in Windaq
     • For FFT size of 8192, up to 7 channels can be enabled in Windaq
     • For FFT size of 16384, up to 3 channels can be enabled in Windaq
     • For FFT size of 32768, only 1 channel can be enabled in Windaq (This is for registered user only)
2. True full ADC resolution (see side-by-side comparison below) No more need for the Dynamic Amplifier option available in the first generation of FFT
3. The display of FFT II is sizable  
4. Channel number is a 0-based index to Windaq's scanlist. For example, if Windaq has channel 3,4,6,7 enabled, one can enter 0 for channel 3, 1 for channel 4, 2 for channel 6 and 3 for channel 7. Must read: The mystery of channel index!

5. Three scaling options for the frequency axis:

   • Standard Frequency Scaling, each pixel line represents one frequency component and you may use the horizontal scroll bar to scroll the interested frequency range into view.

   • Logarithmic Frequency Scaling,  to fit the full frequency range to the charting area with a logarithmic scale. This is perfect to generate a frequency response like what you see in an audio engineering chart. If Chart persist is checked, you may run a sweeping signal through the whole frequency range and see a frequency response chart of your sensor.
     
     

   • Full-fit Frequency Scaling,  to fit the full frequency range to the charting area with a linear scale

6. While acquiring spectrum, you may
   1. use the left mouse button to drag the waveform up and down
   2. double-click the left of right mouse buttons to change the scaling of the waveform. 
   3. adjust the Analog oscilloscope-like persistence control to study the trend of the spectrum (Refer to the above screen shot for visual effect)
   4. push down the right mouse button to enable a vertical cursor to exam to the waveform.
   5. click on AutoSet button to bring a weak signal into sight immediately
7. Once you stop the live frequency display, you may 
   1. push down the left mouse button on the chart to enable a vertical cursor and drag it around to study the spectrum
   2. push down the right mouse button on the chart to enable a cross hair and drag it around to study the spectrum
8. Intelligent Channel Select: Highlight/Select a channel in Windaq and fire up this Windaq add-on, and it will use the selected channel as its default channel

Side-by-side comparison of FFT II and FFT (the signal is totally buried in the noise under the orginal version of FFT)