Spectrum Analyzer（频谱分析仪）

Spectrum Analyzer in 1.2 and earlier

Spectrum Analyzer

This plugin visualizes the frequencies present in the signal it monitors.

Graph

• X axis: shows frequencies from 20 Hz to 20,000 Hz, divided into octaves (this makes the X axis appear nonlinear).

• Y axis: shows amplitude from 40 dB to -60 dB (displayed linearly with respect to decibels).

Buttons

• Linear Spectrum: toggles linear display of frequencies (rather than by octaves).

• Linear Y axis: toggles linear display of amplitude (rather than by decibels).

Spectrum Analyzer in 1.3 and later

Spectrum Analyzer

• Frequency Range : alters the range of displayed frequencies.

• Amplitude Range : alters the range of displayed amplitude.

• FFT Block Size : alters the frequency resolution of the display (Higher resolutions come at the cost of FPS).

• FFT Window Type : changes algorithm used to remove FFT-related noise.

  • Blackmann-Harris displays the least noise but has low frequency resolution.

  • Rectangular displays the most noise but has high frequency resolution.

Graph

• X axis: shows frequencies based on the Frequency range drop-down menu.

• Y axis: shows amplitude based on the Amplitude range drop-down menu.

Clicking in the spectrum/waterfall display adds a ruler/cursor with value readouts.

Advanced

• Envelope Res: alters the resolution of the Peak envelope ("Peak Hold").

• Spectrum Res: alters the resolution of the display curve with fill-in color.

• Falloff Factor: alters the speed at which the peak envelope ("Peak Hold") falls to zero.

• Averaging Weight: alters how the display curve reacts to new samples.

  • High value: fast reaction, low jitter reduction. enables real-time spectrogram.

  • Low value: slow reaction, high jitter reduction.

• Waterfall Height: alters the time range, or the amount of temporarily stored frames, of displayed frequencies in the Waterfall display.

• Waterfall Gamma: alters the amount of gamma correction in the Waterfall display.

• Window Overlap: alters how many times each FFT sample is processed (higher values can help improve FPS).

• Zero Padding: improves resolution when using a smaller FFT Block size, at the cost of performance.