IOScope FFT Analyzer Options

Input Options

Y
Tap the Y row in the table to see a list of possible signals to choose from for the Y input. The Y signal represents the output of the system or device under test (DUT).
X
Tap the X row in the table to see a list of possible signals to choose from for the X input. The X signal represents the input to the system or device under test (DUT). It is typically referred to as the reference signal.
X Delay
The reference input can be delayed by any amount of time from zero up to the measurement duration. This allows you to time-align the X and Y inputs for the highest quality measurements. This can be particularly important for measurements involving significant acoustic delays (expect roughly an additional millisecond of delay for every foot of sound propagation through air).

Measurement Length
Up to 15 additional vertical cursors may be automatically placed at harmonics (integer multiples) of the current (fundamental) cursor frequency.
Max Frequency Res
When working with multiple channels in the FFT analyzer, this option lets you choose which channel the horizontal cursor bar will be associated with.

Averaging
Successive measurements may be averaged according to the selection of this segmented control. Available average types include: Linear (Stable) and Exponential. Linear averaging weights all measurements equally. Exponential averaging applies an exponential weighting such that more recent measurements contribute to the current average value more than older measurements. When linear averaging is selected, the analyzer will automatically stop after the specified number of averages has been reached.
Averages
The number of measurements to include in the current average is specified in the Averages text box. When linear averaging is the selected average type, the analyzer will automatically stop after the specified number of measurements have been included in the average. Exponential averaging allows the analyzer to continue running even after the specified number of measurements have been processed. The exponential average can be thought of as including only the most recent N (time-weighted) measurements, where N is the specified number of averages.