Dual FFT Analyzer

Frequency Domain Analysis

The Dual FFT Analyzer's available frequency domain measurements include:

  • Frequency response magnitude (Mag)
  • Frequency response phase (Phase)
  • Coherence
  • Group delay
  • Phase delay

The frequency resolution can be adjusted from 10 Hz to as fine as 0.0625 Hz, which corresponds to FFT lengths of 4800 to 768000 lines (2400 to 384000 visible spectral lines) at a sample rate of 48 kHz.

  • For best results with long measurements (measurements with a fine frequency resolution), running only the SignalScope X app after a fresh reboot of the device is recommended.

Measurement selection is available within the upper and lower plot options, menus, which can be accessed from the Dual FFT Analyzer's toolbar.

Time Domain Analysis

IOScope's available time domain measurements include:

  • Impulse response (IR)
  • Squared Impulse Response
  • Cross-correlation

The measurement duration can be adjusted from 0.1 to 16 seconds. These measurement durations correspond to frequency resolutions from 10 Hz to 0.0625 Hz, which correspond to FFT lengths of 4800 to 768000 lines (2400 to 384000 visible spectral lines) at a sample rate of 48 kHz.

  • For best results with long measurements, running only the SignalScope X app after a fresh reboot of the device is recommended.

Measurement selection is available within the upper and lower plot options, menus, which can be accessed from the Dual FFT Analyzer's toolbar.

A data cursor may be placed within the upper or lower plot with a single tap. You can move the data cursor by sliding your finger to the right or left inside the respective plot. When the cursor is visible, measurement information associated with the cursor is displayed in a small info view above the spectrum display. It is possible to zoom in or out on the plot with a two-finger pinching gesture, and to pan the plot, while zoomed in, with two fingers. A double-tap resets the plot zoom and a second double tap turns off the data cursor. Cursor peak tracking can be cycled between max, min, and off with a triple tap.

A double tap inside the vertical axis label area toggles auto vertical scaling on and off.

Depending on the current auto-scaling state, the vertical scale of the plot may also be altered by a single-finger slide, or with a two-finger pinching gesture inside the vertical axis region (the region containing the vertical axis title and labels).