4 Operation Guide
4.1 Function operation guide
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4 Operation Guide
In this chapter, operating methods of different measurement functions of the 3943B monitoring receiver
are introduced and measurement procedures are explained in detail.
Function operation guide
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4.1 Function operation guide
This section respectively introduces operation methods of basic scan functions of the 3943B monitoring
receiver, including fixed frequency receiving, panoramic scan, frequency scan and list scan. The settings
and operation steps are illustrated with examples.
Fixed frequency receiving
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P a n o r a m i c s c a n
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F r e q u e n c y s c a n
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L i s t s c a n
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4.1.1 Fixed frequency receiving
Fixed-frequency receiving refers to the scan mode in which the receiving frequency is fixed and the data
is continuously collected and measured at this frequency. In fixed frequency measurement and analysis,
the local oscillator of the instrument runs in point frequency mode, which completes the receiving of fixed
frequency, completes a seamless acquisition according to sampling parameters, and saves it in memory,
thus realizing one-time acquisition and omni-directional analysis. Level measurement is carried out on
fixed frequency points, and the signal strength information is obtained by level measurement (field
strength measurement can be carried out after the antenna is installed), so as to monitor the signal. In
order to judge the signal more visually, it is usually necessary to use demodulation processing function to
directly demodulate the audio signal and monitor the sound. At the same time, FFT operation is
performed on the current frequency point to obtain the frequency spectrum within the intermediate
frequency bandwidth, and the task of monitoring signals is assisted by the frequency spectrum diagram.
In the fixed frequency receiving mode, there are three signal processing channels: intermediate
frequency spectrum processing channel, level measurement channel and demodulation channel, and
the parameters of the three processing channels (such as intermediate frequency bandwidth,
demodulation mode, demodulation bandwidth, etc.) can be set independently. This processing scheme
has two obvious advantages. First, users can access the ultra-wide intermediate frequency spectrum
and benefit from the best demodulation bandwidth (the demodulation bandwidth can be very small) at
the same time. Secondly, the level measurement is mainly carried out in the level measurement channel
instead of the intermediate frequency spectrum processing channel, thus ensuring that the signal level
can be accurately measured even for ultrashort pulses.
4.1.1.1 Start of fixed frequency receiving
Step 1.
Set the operating mode. Select [System Menu] to pop up the menu, select [Scan] icon and
[Fixed Frequency Receiving] to enter the fixed frequency receiving mode, as shown in Fig. 4.1.
Содержание 3943B
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