Zero Pad

Zero padding may be used to artificially increase the number of data points included in the FFT. The default is no zero padding and using the 1024 points obtained from the data buffer. The FFT is always 1024 samples around the trigger point even if 2K, 4K or 8K buffer used.

Zero padding will allow the use of either the standard 1K buffer or zero padded 2K, 4K, 8K or 16K data sets.

Increasing the zero padding has the effect of stretching the frequency axis which will allow more accurate measurement with the cursors.


The picture below shows the FFT of a 5V 3.472KHz square wave on channel A and a 4V 1KHz sine wave with no zero padding.

   


The picture below shows the same input signal with x4 zero padding. The scroll bar at the bottom of the screen may be used to scroll back and forth through the data buffer.