NF FRA5087, Instruction Manual

Page: 97 / 194

4.8 Harmonics analysis
FRA5087
4-23
4.8 Harmonics analysis
The FRA5087 analyzes measured data by the use of DFT (discrete Fourier transform) to provide
measurement/analysis results. Normally, measurement/analysis is made for the oscillator output
frequency components. However, the FRA5087 can also measure and analyze those frequency
components that are integer-multiplication of the oscillator output frequency (i.e., frequency
harmonics components), if you set the order of frequency harmonics. You can measure and
evaluate DUT’s non-linear characteristics by using the harmonics analysis operation.
Use the menu [Measure][BASIC FUNCTION][HARMONICS ANALYSIS] to set the order of
harmonics. Select the order from the range of 1 to 10, which enables you to analyze up to tenth
order harmonics. If you set the order to be 1, the fundamental frequency analysis will be made
(for the oscillator output frequency). Setting the harmonics order to be between 2 and 10 will
enable harmonics analysis.
The oscillator output frequency is displayed in the frequency axis of the graph on the LCD screen.
Therefore, the graph display and the maximum measurable frequencies are limited to 10 MHz/n,
when you set the order of harmonics to be n.
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CAUTION
It is possible to set the frequency sweep range beyond 10 MHz/n even if you
have set the order of harmonics at n (  1). If you start frequency sweep
measurement with the setting of the order of harmonics of n (  1), the range of
the graph will be displayed according to your setting and also an information
message will be displayed stating that the actual plotting of data in the graph
will be limited up to 10 MHz/n.
If you try to perform a SINGLE measurement at a frequency beyond 10 MHz/n,
the measurement will not be made and the error message will be displayed.
When the order of harmonics is set at n (  1), the measurement processing will
involve n-times of integration period for removing the fundamental frequency
component. As a consequence, the time period required for measurement and
sweep will be increased to approximately n-times compared with otherwise.
The graph frequency axis scale is in relation to the fundamental frequency.