Ceyear 4051 Series, User Manual

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4. Operating Instruction
4.2 Advanced operation guide
96
Fig. 4.12 Resolution bandwidth requirement when distinguishing small signals
2) Distinguish two signals with frequency difference of 50 kHz and amplitude difference of 60 dB
In this section, a narrow resolution bandwidth is adopted to distinguish two signals with frequency interval of
50 kHz and amplitude difference of 60 dB. Output ports of two signal generators should be connected to the
input port of the analyzer as shown in Fig. 4.7.
Step 1. set frequency of one signal generator at 300 MHz and its amplitude at -10 dBm; set frequency of
the other signal generator at 300.05 MHz and its signal output amplitude at -70 dBm. Turn on RF
output of two signal generators.
Step 2. set the Series Signal Analyzer in spectrum analysis mode and reset:
 Press
【
Mode
】
and [Spectrum].

Press 【 Preset 】 .
Step 3. set parameters of the analyzer:
 Press 【 Frequency 】 , [Center Freq] and enter 300 MHz.
 Press
【
BW
】
, [Res BW Auto
Man
] and enter 30kHz;
 Press 【 Span/X Axis 】 , [Span] and enter 500kHz.
Step 4. Set 300 MHz signal peak to reference level:
 Press
【
Peak Search
】
, [Marker→] and [Marker →
Ref Level
].
Caution
Rectangle coefficient of the resolution bandwidth filter of the analyzer is about 4.1:1. When resolution
bandwidth is 30 kHz, 60 dB bandwidth is 123 kHz and half-band width is 61.5 kHz, larger than the frequency
interval of 50 kHz. Therefore, it is impossible to distinguish two input signals as shown in Fig. 4.13.