TECHNICAL DESCRIPTION AND OPERATING MANUAL ST131 <PIRANHA II> and ST131N
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3.10 “SPECTRAL SUBTRACTION” OPTION
This option can only display those signals that were left after subtracting the current spectrum from
previously created ones.
The main purpose of creation the pattern spectrum is to use it as a legitimate signal spectrogram,
which obviously does not have STM signals within the controlled area. Thus, it provides the sharp
reduction in the amount of signals to be processed by subtracting the pattern spectrum.
Spectrum which subtracts from the current spectrum (hereinafter, the pattern) is created in three
ways:
First method is a one-time creation of a pattern. This
means that the current spectrum becomes the pattern just
by pressing the button. New signals will be displayed in
green color over the background gray pattern (Figure 35).
Activation this method provides by pressing
and selecting
.
Second way is to save pattern in the device’s memory. To do this, go to the "Memory" sub-mode by
pressing
then press
, select the name and click on the rotary knob.
Having been stored in the non-volatile memory of the main unit, this pattern can be used repeatedly.
To use the stored pattern, you need to load it from memory by pressing
and selecting the
desired image. Then press
without leaving the "Memory" sub-mode.
Third method is fundamentally different from previous ones because it does not store the displayed
spectrum but the entire spectrum with a fixed high frequency resolution in the maximum range
frequency limit will be saved.
This way is relevant and implemented to the "RADIO 30-4400 MHz" and "WIRE 30-3000 MHz"
channels. This saved spectrum we will call the detailed pattern.
To create the detailed pattern, go to the “AUTOMATIC
ANALYSIS " sub-mode by pressing
. Next, switch to the
auxiliary context buttons by pressing the rotary knob and press
. If the detailed pattern has been created before, there
will be warning message: "The pattern was created before.
Rewrite it? If YES press '1'. If NO press other key." If the
pattern has not been created previously, the screen will
immediately show an information window of the pattern being
created (Figure 36).
Time to create a detailed pattern is about half an hour.
Finally there will be the message: "Pattern created
successfully. Pattern difference option can be used".
The pattern having been stored in non-volatile memory of the
main unit can be used repeatedly like in the second method. In
addition, it is possible to transfer the detailed pattern to the PC
and save it into a file and then upload it again into the ST131
main unit later. See «ST131 Analyzer Pro. User’s Manual" to get
description of that process.
Figure 35
Figure 36
