Ceyear 4051 Series, User Manual

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Appendix
Appendix A Terminology
713
Where:
MDR
2
: best dynamic range of two-order undistorted measurement
SHI: two-order distortion intercept point
DANL: display average noise level
MDR
3
: best dynamic range of two-order undistorted measurement
TOI: three-order distortion intercept point
Logarithm scale display
The vertical scale on the screen is displayed in logarithm mode. The amplitude units of dBm, dBmV, dBμV,
W and V can be used in logarithm mode.
Spurious response
Spurious signal unwanted on the screen of the signal/spectrum analyzer. The spurious response is divided into
spurious response and residual response, in which spurious response is the abnormal response caused on the
screen of the signal/spectrum analyzer along with the input signal and can be divided into harmonic, image
frequency, multiple and out-of-band response. The spurious response can also be divided into harmonic
response and non-harmonic response, in which non-harmonic response should be intermodulation or residual
response. Detailed description is as follows:
a) Harmonic distortion
When the input signal amplitude increases to enable the mixer to work in nonlinear state, the harmonic
component of such input signal will be produced in the mixer, which is called harmonic distortion.
b) Image and multiple response
During frequency mixing, if two signals can mix with the LO signal with the same frequency to generate IF
signals of the same frequency and if one original signal has a frequency one IF lower than the LO signal and
the other original signal has a frequency one IF higher than the LO signal, then such two original signals can
be referred to as the image of each other. The input signal of each frequency of the LO signal has an image
and the frequency of the original signal and the image differs by two times of IF.
The multiple response refers to double or multiple response caused on the screen by one input signal of single
frequency, which means the signal responds to two or more LO frequencies. The LO frequency capable of
generating the multiple response has an interval of two times of IF. The multiple response can only occur
when overlapping is selected as mixing mode and the LO sweeps a range wide enough to mix the input signal
in more than one mixing mode. Difference signal/spectrum analyzers have different principle structures and
cause the image and multiple response at different frequencies.
c) Residual response
The residual response refers to the discrete response observed on the screen when no input signal enters the
signal/spectrum analyzer.
[FFT]
short for fast fourier transform. It is used for specific mathematical analysis of time domain signals to provide
frequency domain analysis result.
Resolution
Resolution indicates the capacity of the signal/spectrum analyzer to clearly distinguish two input signals. It is
affected by IF filter bandwidth, rectangle coefficient, LO residual frequency modulation, phase noise and