F-15
Applications
1. Fast Fourier Transform (FFT)
Digital oscilloscopes normally display the signal under observation as waveform data in
the time axis domain. By performing an FFT of this digital data, the signal under
observation can be displayed in the frequency axis domain, similar to a spectrum analyzer.
(change energy to power in graph below)
With this product’s FFT, the power spectrum can be displayed.
A power spectrum displays the signal energy (in dBm) of each frequency component of
the waveform that is targeted for computation. 0dBm corresponds to 1mW and the
equivalent voltage (0.316V peak) at a 50
Ω
load.
The power spectrum is expressed in units of dBV (0dBV=1Vrms). To convert this unit,
use the following formula.
dBV=dBm-13.01
2. Aliasing
With a digital oscilloscope, signals having frequencies up to 1/2 of the sampling
frequency (Nyquist frequency) can be observed. If higher frequency components are
observed, they will appear as a waveform of lower-than-actual frequency components
(aliasing).
←
Observed signal
←
Aliased waveform
Sampling clock
Sampling point
↓
Summary of Contents for DS-8814
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Page 19: ...Operation Manual...
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Page 100: ...81 Section 3 Daily Care...
Page 106: ...87 Section 4 Specifications...
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Page 114: ...F 1 Section 5 FFT Computation...
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