Hioki MR8827, Инструкция по эксплуатации

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FFT Analysis Condition Settings
To average time-domain waveform values
Waveforms are acquired and averaged within the time domain. FFT calculation is performed
after averaging.
When the trigger mode is [Auto] : When the START key is pressed, data will be acquired after a
certain interval even if trigger criteria are not met. This means that if averaging is applied to an
asynchronous signal, the resulting data is meaningless.
Synchronous signals have better SNR (signal-to-noise ratio) and are more suitable for analysis.
To average spectrum values
Acquired data is first subject to FFT analysis. After analysis, averaging is performed within the
frequency range, and the result is displayed. This differs from time-domain averaging in that
averaging can be performed without trigger synchronization. However, if the characteristics of the
input waveform allow triggering, using the trigger for synchronization is recommended.
To retain peak value on spectrum (peak hold)
After performing FFT calculations on the acquired waveform, peak values are retained (held) and
displayed within the frequency range.
■ FFT Analysis Modes and Averaging

: Can be set,
—
: Cannot be set,
¡
: Can be partially set
Analysis mode
Averaging
Time-domain
waveform
averaging
Spectrum averaging
Simple Exponential Simple Exponential
Peak
hold
OFF — — — — —
Storage Waveform
 
— — —
Histogram
 
— — —
Linear Spectrum
  ¡
*2
¡
*2
¡
*2
RMS Spectrum
  ¡
*2
¡
*2
¡
*2
Power Spectrum
    
Power Spectrum Density
*1
    
LPC analysis (Power Spectrum Density)
*1
 
— — —
Transfer Function
  ¡
*2
¡
*2
¡
*2
Cross Power Spectrum
  ¡
*2
¡
*2
¡
*2
Impulse Response
    
Coherence Function — —
 
—
Phase spectrum
 
— — —
Auto-correlation Function
    
Cross-correlation Function
    
1/1 Octave Analysis
*1
    
1/3 Octave Analysis
*1
    
*1. Not available for external sampling
*2. Not available when the y axis is real (linear) or imaginary (linear), and for Nyquist plots
13
FFT
Function