Spectrum Generator

Spectrum Generator creates editable one-dimensional spectrum data for analysis workflows. It supports random power spectral density (PSD) and frequency response function (FRF) generation.

Input and output

• Input: none.
• Output: one histogram/spectrum result (HISTOGRAM 1).

Spectrum type

RandPSD

Use a frequency–amplitude breakpoint table to generate a random PSD curve. Frequency values must be positive and strictly increasing; at least two rows are required, and every amplitude must be greater than zero.

• PSD Type: Acceleration, Velocity, or Displacement.
• PSD Unit: unit options change with the selected PSD type.
• Number of Bins: 100, 200, 500, 1,000, 2,000, 5,000, or 10,000.
• Interpolation Method: Log or Linear.
• Channel Name and Channel No.: output channel identification.

FRF

Use the breakpoint table to define a frequency response function. Provide at least two positive, strictly increasing frequency rows, then select one representation:

• Real and Imaginary: enter real and imaginary components.
• Magnitude and Phase: enter magnitude and phase; magnitude cannot be negative.

Input Unit and Response Unit are required. The generated FRF retains these units and can be connected to Convolution in FRF + Time Domain mode.

Usage notes

• Use RandPSD as the source for PSD to Time Series, or for spectrum display and vibration/fatigue workflows that accept PSD data.
• Use FRF together with a time-series excitation in Convolution to calculate a response time history.
• Logarithmic interpolation requires positive frequency and PSD breakpoint values; use linear interpolation when the data include values unsuitable for log interpolation.