go2signals go2signal-analyzer

The analysis offers a range of tools specialized in the analysis of PSK-modulated signals.

• Determine modulation parameters like PSK modulation type, symbol-rate, version, etc.
• Multiple squared signal spectra display with automatic frequency correction
• N’th power spectrum of phase center offset frequency measurement
• A3 Spectrum symbol rate measurement
• Absolut I/Q display with PLL and differential I/Q display
• Differential phase histogram

The analysis offers a range of tools specialized in the analysis of Offset-QPSK (OQPSK) modulated signals.

OQPSK is a special case of QPSK (aka PSK-4A), where the Q-branch is shifted (offset) by half a symbol duration relative to the I-branch - before transmission. The offset reduces the variation of the envelope - compared to a usual QPSK waveform.

• Determine modulation parameters like OQPSK modulation type, symbol-rate, etc.
• Two squared signal spectra display with automatic frequency correction
• 4’th power spectrum of phase center offset frequency measurement
• A3 Spectrum symbol rate measurement
• Absolut I/Q display with PLL and differential I/Q display
• Absolut I/Q display with PLL of even and odd symbols
• Differential phase histogram

The analysis offers a range of tools specialized in the analysis of multicarrier PSK/QAM modulated signals.

• Determine modulation parameters like multicarrier PSK and QAM modulation type, symbol-rate, channel count, channel distance, etc.
• Autocorrelation channel/carrier count and distance measurement
• Average spectrum with channel position markers, numbers and selection
• A3 Spectrum symbol rate measurement of selected channel/carrier
• Differential I/Q display of selected channel/carrier

The automatic estimation of parameters uses statistical properties of the signal. The analysis performs best on strong (high SNR), undistorted signal. Idle or repeating symbol sequences may lead to confusing analysis results.

The analysis offers a range of tools specialized in the analysis of QAM modulated signals.

• Determine modulation parameters like PSK and QAM modulation type, symbol-rate, etc.
• High performance blind equalizer supporting many different PSK and QAM modulation types from PSK2,4,8,16,32 up to QAM4,8,16,32,64,128
• Spectrum symbol rate measurement with selectable clock metric
• Raw and equalized I/Q display
• Equalizer error based symbol quality analysis

This module provides a tool for manual analysis of emissions using frequency shift keying (FSK) with multiple tones (>= 4). Various metrics are calculated and displayed as plots, enabling the user to determine the parameters of the modulation.

• Determine modulation parameters like MFSK modulation type, tone count, tone duration, tone distance, etc.
• Spectrogram with automatic tone marking
• Histogram over tone frequencies for tone distance measurement
• Tone number histogram
• F3 spectrum symbol rate measurement

In contrast to the FSK analysis, more than 4 tones can be determined and measured.

The analysis offers a range of tools specialized in the analysis and demodulation of OFDM modulated signals.
OFDM signals are a special case of multi-carrier modulated PSK/QAM signals.

The analysis performs an automatic estimation of the basic modulation parameters. These parameters can be checked by the user and modified if necessary. .

The following parameters can be measured using the analysis results:

• Carrier scatter plots for differential phase, absolute phase and magnitude
• Time behavior scatter plots for differential phase, absolute phase and magnitude
• Multicarrier absolute and differential I/Q display
• Decision directed PLL absolute and differential demodulation for PSK2, PSK4, PSK8, PSK16, QAM4 and QAM16 modulation
• Multicarrier absolute and differential soft decisions symbols I/Q display
• Bit display for demodulation result
• Special multicarrier PSK/QAM mode with phase and pulse form correction
• Analysis result export to go2monitor and go2modem-studio as modem description or demodulator parameter file

The following assumptions and restrictions apply:

• The analyzed signal is an OFDM or a multi-carrier PSK/QAM signal
• Optimal results can be expected only for OFDM signals employing a cyclic prefix (CP-OFDM)
• There is enough signal available for processing, at least a few hundred symbols are recommended:
• The analysis performs best on strong (high SNR) and undistorted signals.
• Repeating symbol sequences (e.g. idle sequences and pilots) may lead to confusing analysis results.

The entries in the “Preprocessing” menu are used to process an input signal before the actual analysis. Some modulation methods require analog pre-processing before go2studio-analyze modules can be used successfully.

• AM is used to remove analog AM modulations
• FM is used to remove analog FM modulations
• Crop is used to reduce the file size so that go2studio-analyze can work faster
• DeChirp is used to remove a linear chirp up or down modulation

This module offers simple audio playback to give you immediate feedback on the sound. The adjustable frequency range used is displayed in a separate sonogram. An additional horizontal line shows the current playback position.
The following demodulators are available:

• DIG/CW
• USB
• LSB
• AM
• FM

The classification analysis module runs an automatic signal classification of a selected part of a signal. All relevant signal parameters are displayed in a table if the classification was successful, otherwise only
generic parameters are displayed.

• Automatic modulation classification of a signal contained within selection
• Includes modem classification
• See "Technical Data" for supported modulation and modem types

The Time Analysis module provides various time domain diagrams for manual analysis of basic emission characteristics, e.g. the modulation type of an emission.
The Time Analysis shows three diagrams that can contain:

• Amplitude
• Phase
• Frequency
• Amplitude (I+Q)
• Real (in phase)
• Imaginary (quadrature)
• Power (squared magnitude, lin.)
• Level (log. power)
• Initial configured for time behavior of instantaneous magnitude, phase and frequency comparison (AM, PM and FM demodulation)
• Additional instantaneous signals (amplitude, in-phase, quadrature, power and level) selectable
• Each plot with additional histogram