Ceyear 4051 Series, User Manual

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4. Operating Instruction
4.2 Advanced operation guide
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Step 6. Turn off marker count function:

Press 【 Marker Func 】 , [Marker Count ▶ ] and [Marker Count On Off].
Caution
When using the frequency count function, if users find that sweep speed of the analyzer is dropping, it is
normal because it takes longer for the analyzer to execute accurate signal locating and IF counting in the
background.
Caution
When using the frequency count function, the signal generator to be measured and the analyzer should share
the same time base in order to accurately measure the frequency.
Fig. 4.30 Improve count accuracy by changing the gate time
4.2.5 Noise signal measurement
4.2.5.1 Concept of noise measurement
In communications systems, signal-to-noise ratio (SNR) is usually used to express noise amplitude. When the
nose level in the system increases, SNR decreases and it will be harder to demodulate modulated signals. SNR
measurement is also used to indicate measurement of ratio of carrier against noise in communications systems.
In the following example, the way to measure SNR and noise with marker function of 4051 Series
Signal/Spectrum Analyzer will be introduced. In the example, SNR is measured with the signal (carrier)
having only single frequency point. If the system to be measured has modulated signal, testing procedures
have to be modified to correct the level of such modulated signal.