The classifier user interface consists of a settings screen and two windows:
Ø An FFT window
Ø A list of classified signals
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Press the Classifier button to launch the classifier or select it in one of the analysis menus or selectors. |
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Press the Start/Stop Classifier button to restart the classification. |
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When the Classifier is launched a label positioned in the left-hand side of the upper status line indicates the selected frequency range and the acquisition mode. |
FFT Window
The upper FFT window is shown with five signals classified in manual mode.
Classifier Settings
Settings are accessed through the Options | Classifier Settings menu.
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Modulation |
Check any number of modulation types or voice using the appropriate check boxes to narrow down the range of recognized signals. |
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Continuous Mode |
If continuous classification is desired check this box. Continuous mode can be halted and restarted pressing the Start/Stop Classifier button. If the Continuous Mode check box is left unchecked, each classification must be started manually by pressing the Start/Stop Classifier button. The classifier allows only one classification attempt at a time. During classification attempts the Start/Stop Classifier button is grayed out. |
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Refresh List
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If the Refresh List check box is checked, the list of results will be cleared after each classification attempt. This feature is only available when continuous mode is selected. |
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Cycle Mode |
This parameter sets the interval between classification attempts if no signals were classified. Enter a restart cycle length ranging from 4 s to 3600 s. Samples are available from two sources: Samples taken before the classifier was started (select Previous Samples). Samples taken after the classifier was started (select New Samples). |
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Sample Time
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Choose a sample time of 1.6 or 3.2 s. The probability of correct classification of low symbol rate signals increases when the higher sample time is selected. |
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OFDM Mode
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If Full Analysis is selected the modulation format of the OFDM subcarriers is also analyzed. If Partial Analysis is selected, the modulation format of the subcarriers is not analyzed. |
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30 Bd CW-Morse Protection |
Checking this box will introduce a feature to prevent the classifier from confusing CW and FSK signals at the edges of the sampled input bandwidth. |
Use Demodulator | Center… or double-click in the Center in the lower status bar for selecting an appropriate center frequency.
To select the classification bandwidth, double-click in the Bandwidth field in the lower status bar or open a menu list by right-clicking in the FFT window. The Average Factor, Window Type, Period and Peak Hold options in the menu list are identical to the same real-time FFT options.
Classification Results List
The list is ordered in self-explanatory columns.
Each signal in the list is labeled and numbered as Signal n, and in manual mode this corresponds to the Sn signal marker in the FFT window – the marker is a box surrounding the signal envelope.
Certain signals listed below can be further studied in an additional graphical view by double-clicking on the desired signal in the results list. This function is not available in continuous mode.
If no panes are available this message is displayed:
Three panes are available:
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CW
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Amplitude transitions are displayed along a time axis.
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FSK
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Frequency transitions are displayed along a time axis. The values of two frequencies of the FSK signal are displayed on the vertical axis.
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MFSK |
Frequency transitions are displayed along a time axis. The values of the frequencies of the MFSK signal are displayed on the vertical axis.
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PSK
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Phase transitions are displayed along a time axis – the red graph shows the value of the real component of the signal (the I component) and the green graph shows the value of the imaginary component of the signal (the Q component).
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Baudrate Spectrum
This pane displays a probability spectrum of the instantaneous baud rates contained in the analyzed signal. The value of the highest probable rate is marked by a vertical, dotted marker and numerically displayed in a Baudrate box below the pane.
Moving the mouse cursor across this pane changes the cursor into a crosshair, which can be used to determine the baud rate for individual spectral components. The baud rate value pointed to by the crosshair is displayed in a Cursor position box below the pane.
Differential Symbols
Phase plane display showing the differential phase constellation of the signal. This pane is only available for PSK signals.
