Ceyear 4051 Series, User Manual

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8. Specifications and test methods
8.5 Performance characteristics test
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Fig. 8.6 Schematic diagram of maximum analysis bandwidth test
2) Set the 4051 analyzer as I/Q analysis mode and the frequency domain window as current window. Set the
center frequency as 1 GHz and the analysis bandwidth as 10 MHz.
3) Set the frequency of synthesized signal generator#1 as 1 GHz and the amplitude as -10 dBm; execute
Marker Delta and turn off the output of signal generator #1. Set the frequency of synthesized signal
generator#2as 1 GHz and the amplitude as -10 dBm; adjust the output of signal generator#2 to ensure the
Marker Delta reading is closest to 0 dB.
4) Gradually reduce the frequency of signal generator #2 and execute Peak Search. If the marker amplitude
reading is less than -3 dB, note the current output frequency of the signal generator as left limit value,
otherwise record the frequency value at the left-most graticule of the 4051 analyzer screen and record the
result in the fL column in the 4051 Auxiliary Form.
5) Turn off the output of signal generator #2 and turn on the output of signal generator#1.
6) Turn on and gradually increase the frequency of signal generator #1 and execute Peak Search. If the
marker amplitude reading is less than -3 dB, note the current output frequency of the signal generator as
right limit value, otherwise record the frequency value at the right-most graticule of the 4051 analyzer
screen and record the result in the fR column in the 4051 Auxiliary Form.
7) If bandwidth option H38A or H38B is available, repeat step 2 ~ 6 based on the set value of relevant
analysis bandwidth in B7 of the 4051 Auxiliary Form.
d) Test records and data processing
8) Calculate the maximum analysis bandwidth measurement value BWMAX according to the formula (14)
and record the result in the 4051 Record Sheet. Otherwise, the record will be considered not compliant
with relevant requirements.
Where, f R refers to the right limit value (MHz);
f
L
refers to the left limit value (MHz).
8.5.1.1.12 Video bandwidth
a) Test items
The video bandwidth refers to the bandwidth of the tunable low-pass filter in the video circuit behind the
detector of the signal/spectrum analyzer. The video filter is the low-pass filter located behind the detector for
defining the bandwidth of the video amplifier. It can smooth the noise and is used to average or smooth traces.
Besides, it can easily detect weak signals in noises. Change of the video bandwidth does not affect the
frequency resolution of the 4051 analyzer, but too narrow video bandwidth may lead to increase in the sweep