
254
FFT Calculation Types
Calculation types and internal calculation formulas
Calculation type
Internal calculation formula (real: real part, imag: imaginary part, log: logarithm)
Off
Does not perform any calculation.
Linear spectrum
𝑋𝑋(𝑘𝑘) = ∑ 𝑥𝑥(𝑛𝑛)𝑊𝑊
𝑘𝑘𝑘𝑘
𝑁𝑁𝑁𝑁
𝑘𝑘𝑛𝑛
𝐹𝐹(𝑘𝑘) = 𝐶𝐶𝑋𝑋(𝑘𝑘)
𝐶𝐶
=
{1/𝑁𝑁(𝐷𝐷𝐶𝐶)
2/𝑁𝑁(𝐴𝐴𝐶𝐶)
𝑙𝑙𝑙𝑙𝑛𝑛𝑙𝑙𝑙𝑙𝑙𝑙 = |𝐹𝐹(𝑘𝑘)| 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = 𝑟𝑟{𝐹𝐹(𝑘𝑘)} 𝑙𝑙𝑖𝑖𝑙𝑙𝑖𝑖 = Im{𝐹𝐹(𝑘𝑘)}
log
=
20log|𝐹𝐹(𝑘𝑘)|
RMS spectrum
𝐹𝐹𝐹(𝑘𝑘) = 𝐶𝐶𝐹𝐹𝐹(𝑘𝑘)
𝐶𝐶𝐹
=
{
1 (𝐷𝐷𝐶𝐶)
1/√2(𝐴𝐴𝐶𝐶)
𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = |𝐹𝐹𝐹(𝑘𝑘)| 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = Re{𝐹𝐹𝐹(𝑘𝑘)} 𝑙𝑙𝑖𝑖𝑙𝑙𝑖𝑖 = Im{𝐹𝐹𝐹(𝑘𝑘)}
log
=
20log|𝐹𝐹𝐹(𝑘𝑘)|
Power spectrum
𝑃𝑃(𝑘𝑘) = 𝑎𝑎|𝐹𝐹(𝑘𝑘)|
2
𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑎𝑎𝑙𝑙 = 𝑃𝑃(𝑘𝑘)
log
=
10log|𝑃𝑃(𝑘𝑘)|
𝑎𝑎
=
{1 (𝐷𝐷𝐷𝐷)
1/2 (𝐴𝐴𝐴𝐴𝐴
Phase spectrum
𝜃𝜃(𝑘𝑘)
=
180/𝜋𝜋
×
tan
−1
(Im(𝐹𝐹
′
(𝑘𝑘))/Re(𝐹𝐹
′
(𝑘𝑘))
)
𝜃𝜃(𝑘𝑘)
=
180/𝜋𝜋
×
tan
−1
(Im(𝑆𝑆
𝑦𝑦𝑥𝑥
(𝑘𝑘))/Re(𝑆𝑆
𝑦𝑦𝑥𝑥
(𝑘𝑘))
)
Cross power spectrum
𝑆𝑆
𝑦𝑦𝑦𝑦
(𝑘𝑘) = 𝑋𝑋
∗
(𝑘𝑘)𝑌𝑌(𝑘𝑘):
𝑋𝑋
𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝
(𝑘𝑘) = 𝐴𝐴𝑆𝑆
𝑦𝑦𝑦𝑦
(𝑘𝑘)
𝐴𝐴 = 𝐴1/𝑁𝑁
2
2/𝑁𝑁
2
𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = 𝑙𝑋𝑋
𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝
(𝑘𝑘)𝑙 𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = Re{𝑋𝑋
𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝
(𝑘𝑘)}
𝑙𝑙𝑖𝑖𝑙𝑙𝑖𝑖 = Im{𝑋𝑋
𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝
(𝑘𝑘)}
log
=
10log𝑙𝑋𝑋
𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝𝑝
(𝑘𝑘)𝑙
(DC)
(AC)
Cross spectrum
Transfer function
𝐻𝐻(𝑘𝑘) = 𝑌𝑌(𝑘𝑘)/𝑋𝑋(𝑘𝑘)𝑋
𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = |𝐻𝐻(𝑘𝑘)|𝑋𝑋𝑋𝑋𝑋𝑋𝑋𝑋𝑙𝑙𝑙𝑙𝑙𝑙𝑙𝑙 = Re{𝐻𝐻(𝑘𝑘)}𝑋 𝑋𝑙𝑙𝑖𝑖𝑙𝑙𝑖𝑖 = Im{𝐻𝐻(𝑘𝑘)}𝑋 𝑋
log
=
20log|𝐻𝐻(𝑘𝑘)|
Coherence function
𝑐𝑐𝑐𝑐ℎ(𝑘𝑘) = √
𝑆𝑆
𝑦𝑦𝑦𝑦
(𝑘𝑘)𝑆𝑆
𝑦𝑦𝑦𝑦
∗
(𝑘𝑘)
𝑆𝑆
𝑦𝑦𝑦𝑦
(𝑘𝑘)𝑆𝑆
𝑦𝑦𝑦𝑦
(𝑘𝑘)
HIOKI MR6000A966-03
Содержание Memory HiCorder MR6000
Страница 2: ...HIOKI MR6000A966 03...
Страница 56: ...50 Displaying Measured Values HIOKI MR6000A966 03...
Страница 152: ...146 Triggering the Instrument Using CAN Signals CAN Trigger HIOKI MR6000A966 03...
Страница 194: ...188 Numerical Calculation Types and Descriptions HIOKI MR6000A966 03...
Страница 266: ...260 Configuring the Display Settings HIOKI MR6000A966 03...
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