Ceyear 4051 Series, User Manual

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4. Operating Instruction
4.2 Advanced operation guide
107
4.2.3 Measure small signals
Noise produced inside the Series Signal Analyzer determines the ability of the analyzer to measure small
signals and the following methods can be used to change measurement settings in order to increase
measurement sensitivity of the analyzer.
4.2.3.1 Reduce RF attenuator decrement to measure small signals
The input attenuator affects input signal level. If the input signal is very close to the noise floor, reduction in
attenuator decrement may help to extract the signal from the noise.
Caution
Total power of all signals of the analyzer should be kept under +30 dBm (1 W)!
Step 1. reset the Series Signal Analyzer:

Press 【 Preset 】 .
Step 2. Set the signal generator and connect the Series Signal Analyzer:
 Set the signal generator frequency as 300 MHz and amplitude as -80 dBm; connect RF output of the
signal generator to the input port of the analyzer.
Step 3. set center frequency, frequency span and reference level of the analyzer:
 Press 【 Frequency 】 , [Center Freq] and enter 300 MHz.
 Press
【
Span/X Axis
】
, [Span] and enter 5 MHz.

Press 【 Amplitude/Y Axis 】 , [RefLevel] and enter -40 dBm.
Step 4. move the signal peak to the center frequency (300 MHz in this case):
 Press
【
Peak Search
】
and [Marker → Center Freq].
Step 5. reduce frequency span to 1 MHz and if necessary, repeat step 4 to ensure the signal peak in at
the center frequency of the analyzer:
 Press
【
Span/X Axis
】
, [Span] and enter 1 MHz.
Display as shown in Fig. 4.23.