13.3 Setting FFT Analysis Conditions
219
13
Chap
ter
13 FFT
Fun
cti
on
By specifying a setting factor (rate) to be applied to the input signal, the display of data exceeding the result-
ing threshold can be emphasized. This feature is useful for viewing waveforms that may otherwise be
obscured by noise.
The reliability of phase spectrum values is poor when discrete Fourier transform values are extremely small.
For example, in the case of a pure sine wave, almost all phase values at frequencies other than the input fre-
quency result from calculation errors. By treating the maximum value of the power (or cross-power) spectrum
of the input signal,
P
max
, as a reference value, data that exceeds that value multiplied by rate
R
can be dis-
played with emphasis.
13.3.8 Emphasizing Analysis Results (phase spectra
only)
Power Spectrum
Phase Spectrum
Emphasis
Display
10log
P
max
[dB]
10log
RP
max
[dB]
Attenuation Rate and Value
Attenuation value: A [dB]
Attenuation rate: R
-A = 10log
10
R
1 x 10
-6
≤
R
≤
1
0
≤
A
≤
60
1
Enable the highlighting function.
Move the cursor to the
[Highlight(phase)]
item.
Select
2
Set the attenuation rate or attenuation value.
To set an attenuation rate
Move the cursor to the
[Attenuation rate]
item.
Enter the attenuation rate.
See:
To set an attenuation value [dB]
Move the cursor to the
[(db)]
item.
Enter the attenuation value.
See:
Off
Emphasis display disabled. (default setting)
On
Emphasis display enabled.
Procedure
To open the screen: Press the
STATUS
key
→
[Status]
sheet
1
2
3
Summary of Contents for 8847
Page 1: ...MEMORY HiCORDER Instruction Manual 8847 December 2010 Revised edition 4 8847A981 04 10 12H ...
Page 2: ......
Page 18: ...Operating Precautions 8 ...
Page 26: ...1 4 Basic Key Operations 16 ...
Page 74: ...4 4 Waveform Observation 64 ...
Page 98: ...5 5 Managing Files 88 ...
Page 110: ...6 6 Miscellaneous Printing Functions 100 ...
Page 126: ...7 8 Seeing Block Waveforms 116 ...
Page 160: ...8 10 Making Detailed Settings for Input Modules 150 ...
Page 198: ...10 6 Numerical Calculation Type and Description 188 ...
Page 296: ...15 7 Controlling the Instrument with Command Communications LAN USB 286 ...
Page 304: ...16 2 External I O 294 ...
Page 362: ...Appendix 5 FFT Definitions A28 ...
Page 368: ...Index Index 6 ...
Page 369: ......
Page 370: ......
Page 371: ......