Ceyear 4041 Series, User Manual

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Chapter IV Spectrum Analyzer Mode
51
pulse repetition interval (PRI), and its reciprocal is the pulse repetition frequency (PRF).
Fig 4-24 Measurement of pulse repetition frequency
4) Measurement of peak pulse power
As so far, we have known the main lobe amplitude and pulse width, and it is easy to know the resolution
bandwidth of the spectrum analyzer. We can obtain the peak pulse power according to these parameters.
When the spectrum analyzer is under the wide band measurement mode:
Peak pulse power = (main lobe amplitude) - (20 log T
eff
×BW
i
)
Where:
T
eff
——
Pulse width, unit: s
BW
i
——
Impact bandwidth, unit: Hz (1.5

resolution bandwidth used to measure the pulse width)
When the spectrum analyzer is under the narrow band measurement mode:
Peak pulse power = (main lobe amplitude) - (20 log T
eff
×T)
Where:
T
eff
——
Pulse width, unit: s
T
——
Pulse repetition frequency
It is called the pulse desensitization when the peak pulse power does not equal the main lobe amplitude. The pulse
signal does not reduce the sensitiveness of spectrum analyzer. To be exact, the desensitization is due to that the
power of continuous wave (CW) carrier of pulse modulation is distributed to numerous spectrum components (i.e.,
carrier and sideband). Therefore, each spectrum component only contains a part of the total power.