TECHNICAL DESCRIPTION AND OPERATING MANUAL ST131 <PIRANHA II> and ST131N
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receiving and transmission of audio information with the use of a headset.
Emitted power devices of this standard varies from relatively high up to tens of milliwatts (data
transmit), and tens microwatts (wireless headsets of cell phones).
Additional complexity of its
detection is applicable use in this standard
the method of pseudorandom frequency
hopping (FHSS). In this case it is
recommended to use the "WATERFALL"
option of software.
LTE FDD (4G)
Signals have noise-like structure. Radiated power amounts tens of milliwatts.
4.1.4.2.2
Detection of a single RF pulse (hereinafter referred to SRFP)
In the context of the purpose of the ST131 to the sources of pulsed signals are the STM which
preliminary accumulate and subsequent transfer the information by radio (so-called "pulse
transmitters").
In all modes, a single RF pulse duration of 500 ms or more can be detected without gaps.
SRFP are hallmarks: indefinite time and rare appearances on the air (e.g., once a day), a broad
band signal (tens of MHz) and the relatively high radiated power (up to several watts).
SRFP detection involves the use of a peak-hold detector function and spectral subtraction. Detected
signal from SRFP will be presented in the form of spectral lines. Information about the time of the signal
and its duration is absent.
Localization the STM with SRFP transmission is almost impossible by using the amplitude
method because of too short lifetime signal. In this case it is recommended to use alternative
methods of searching STM: visual, non-linear locations, etc.
4.1.4.2.3
Detection of RF pulse sequence (RFPS).
In context of purpose of the ST131 to the sources of such sequences are the STM with different
variants of pulse modulation, such as pulse-width (PWM), pulse-position (PPM), pulse-code
(PCM), pulse-amplitude (PAM), as well as combinations thereof.
RFPS is detected in the frequency and time domains.
Comparison analysis of the frequency and time domains:
Advantages
Disadvantages
Spectrum
Detection across the entire
frequency
Low detectability.
Lack of information about the
duration and period of signal
Oscilloscope
High sensitivity
Detection in a band not more
than 60 MHz.
Absence of reliable information
about the frequency and level of
signal
