SignalScope Pro FFT Analyzer Options

FFT Options

Frequency Resolution
SignalScope Pro simplifies FFT configuration by allowing you to choose a frequency resolution for narrowband spectral analysis. SignalScope Pro then automatically calculates the FFT length required for that frequency resolution at the audio input hardware's current sample rate. It should be noted that in this case, frequency resolution refers to the distance between adjacent spectral lines (or frequency bins) in the spectrum. The smallest frequency difference over which two independent sinusoids can be resolved will also remain a function of the FFT analyzer's data window type.
Data Window
SignalScope Pro provides a selection of different data windows that may be applied to the time domain data before the application of the FFT. The data windows offer different trade-offs between spectral resolution and spectral leakage.
The available data windows include:
- Uniform (rectangular)
- Bartlett
- Blackman
- Flat Top
- Hamming
- Hann (Hanning)
- Rife-Vincent 2
Averaging
Successive spectra for each signal may be averaged according to the selection of this segmented control. Available average types include: Linear (Stable), Exponential, and Peak Hold. Linear averaging weights all spectra equally. Exponential averaging applies an exponential weighting such that more recent spectra contribute to the current average value more than older spectra. Peak Hold keeps the maximum value in each frequency bin over all the spectra included in the measurement (it is not a true average). When either linear of peak hold averaging is selected, the FFT analyzer will automatically stop after the specified number of averages has been reached.
Averages
The number of spectra to include in the current average is specified in the Averages text box. When linear or peak hold averaging is the selected average type, the FFT Analyzer will automatically stop after the specified number of spectra have been included in the average. Exponential averaging allows the analyzer to continue running even after the specified number of spectra have been processed. The exponential average can be thought of as including only the most recent N (time-weighted) spectra, where N is the specified number of averages.

Cursor Options

Harmonic Cursors
Up to 15 additional vertical cursors may be automatically placed at harmonics (integer multiples) of the current (fundamental) cursor frequency.
Horizontal Bar
When working with multiple channels in the FFT analyzer, this option lets you choose which channel the horizontal cursor bar will be associated with.
Peak Track
The cursor may be configured to automatically move to the frequency of the peak value within the current spectrum. The switch turns the peak track function on or off.
Peak Track Channel
When working with multiple channels in the FFT analyzer, this option lets you choose which channel the peak track function will apply to (the channel whose spectral peak will be tracked by the cursor).

Axis Scales

Vertical Axis
Three vertical scale types are available for viewing spectra: Linear, Logarithmic, and dB. The desired scale type is determined by the selection of this control.
Horizontal Axis
Two horizontal scale types are available for viewing spectra: Linear and Logarithmic. The desired scale type is determined by the selection of this control.
Frequency Units
This segmented control lets you choose whether to display frequencies in Hz or cpm (cycles per minute).

FFT Analyzer Options

FFT Options

Cursor Options

Axis Scales

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