Types of Measurements Imported

Every ME’scope package can import multi-channel data from a wide variety of third party data files.  File formats used by all popular multi-channel data acquisition systems, analyzers, recorders, and data collectors are supported.  Over 45 different file formats are supported, including ASCII text spreadsheet, MATLAB, DADiSP, Microsoft WAV, and Universal File Format (UFF UFF is an acronym for Universal File Format. UFF is a disk file format used for exchanging data between different structural testing & analysis systems. Structure models, mode shapes, ODS's, and time or frequency domain measurements can be imported & exported using UFF files. Typical UFF file name extensions are .UFF, .UNV and .ASC.).  ME'scope can import most of the popular kinds of time or frequency domain measurement functions. The following types of measurement functions are recognized by ME'scope.

Time Domain Functions

• Time Waveform (vibration, sound pressure, strain gauge, temperature, etc.)

• Auto Correlation

• Cross Correlation

• Impulse Response Function (IRF)

Frequency Domain Functions

• Fourier Spectrum A Fourier spectrum is also called the Discrete Fourier Transform, or DFT. (FFT FFT is an acronym for Fast Fourier Transform. The FFT algorithm transforms a uniformly sampled time domain signal into its corresponding Digital Fourier Transform (DFT). The Inverse FFT transforms the DFT back into its original time domain signal. The FFT in ME'scope transfroms any number of samples, not just powers of 2. of a sampled Time Waveform)

• Auto Spectrum An Auto Spectrum is calculated by multiplying the Fourier spectrum of a signal by its complex conjugate. The Auto spectrum has magnitude only. Its phase is zero. An Auto spectrum can have either Linear (RMS) units or Power (MS) units. Linear or Power engineering units are chosen in the Linear Power column in the Traces spreadsheet.

• Cross Spectrum A cross-channel function that is calculated by multiplying the Fourier spectrum of a waveform by the complex conjugate of the Fourier spectrum of another waveform.

• Power Spectral Density (PSD PSD is an acronym for Power Spectral Density. A PSD is calculated by dividing an Auto spectrum by its frequency resolution (the increment between frequency lines). PSD units are typically (g^2/Hz) or (g/(Hz^1/2)))

• Frequency Response Function (FRF An FRF (Frequency Response Function) is a cross-channel frequency domain function that defines the dynamic properties of a structure between an excitation Force and the Response caused by that force. An FRF is defined as the ratio (Response DFT / Force DFT). The FRF is a special case of a Transfer Function, where the response is the numerator (Output) and the force is the denominator (Input).) (Response / Force)

• Transfer Function A Transfer function is a cross-channel frequency domain function that defines the dynamic properties between an Output from and an Input to a structure or machine. A Transfer function is defined as the ratio (Output Fourier spectrum / Input Fourier spectrum). An FRF is a special case of a Transfer Function where the Input is an excitaton force, and the Output is the response caused by the excitation force. (Output / Input)

• Transmissibility (Roving response / Reference response)

• Coherence (Ordinary, Multiple & Partial)

• ODS FRF (Roving response Auto Spectrum & phase relative to a Reference response)

• Acoustic Intensity

• Sound Pressure Level