Spektrumanalysator-Software (Spectrum Analyzer Software)

Initialization

• Purpose: Starting the application.
• Logic:
  • Loads the spectrum_analyzer.fxml file to define the UI layout.
  • Applies the style.css stylesheet for visual styling (black background, yellow text, etc.).
  • Creates a window (Stage) titled "Spectrum Analyzer" with a resolution of 1200x800 pixels.
  • Starts the application using launch(args) in the main method.

User Interface and Control

• Purpose: Manages the UI components and user interactions, coordinating updates to the visualization and signal processing.
• Key UI Elements:
  • Sliders: Adjust max frequency (20 Hz to 50 GHz), dynamic range (100–200 dB), and sweep speed (0.1–10).
  • ComboBoxes: Select display mode (Spectrum/Persistence), analysis mode (FFT/Swept-Tuned), window function (Hanning, Blackman-Harris, etc.), and demodulation type (None, AM, FM, etc.).
  • TextFields: Set channel bandwidth and number of channels (1–5).
  • ToggleButton: Enable/disable logarithmic frequency scale.
  • Button: Export power report to a CSV file.
  • Labels: Display metrics like channel power, ACPR (Adjacent Channel Power Ratio), signal type, and window function info.
  • Canvas Containers: Host the spectrum and demodulation visualizations.
• Initialization Logic:
  • Creates a SignalProcessor to handle signal data generation.
  • Initializes SpectrumCanvas (1160x400) and DemodCanvas (1160x150) for visualizations.
  • Sets up listeners for UI controls to update SignalProcessor and SpectrumCanvas parameters (e.g., frequency range, dynamic range, sweep speed).
  • Configures an AnimationTimer to continuously update the canvases and metrics.
• Key Functions:
  • updateMetrics(): Updates labels for channel power, ACPR, and signal type based on SpectrumCanvas calculations and SignalProcessor classification.
  • updateWindowInfo(): Displays window function characteristics (e.g., sidelobe levels, resolution) based on the selected window.
  • exportPowerReport(): Writes channel power and ACPR to a CSV file (power_report.csv).

Signal Processing

• Purpose: Generates simulated signal data, applies window functions, demodulation, and analysis modes.
• Key Parameters:
  • FFT size: 16,384 points.
  • Frequency range: Min (default 20 Hz) to max (default 1 kHz, adjustable).
  • Analysis mode: FFT or Swept-Tuned.
  • Window function: Hanning, Blackman-Harris, Kaiser, Flat-Top, or Gaussian.
  • Demodulation type: None, AM, FM, PM, QAM, PSK, or OFDM.
  • Sweep speed: Affects amplitude attenuation in Swept-Tuned mode.
• Logic:
  • Data Generation:
    • Uses an ExecutorService to run data generation asynchronously.
    • Generates a noise floor based on the max frequency (-160 - 20 * log10(maxFreq / 1000) dB).
    • Simulates signals for specific frequency bands:
      • Wi-Fi (100–200 Hz, +100 dB Gaussian peak at 150 Hz).
      • Bluetooth (2400–2480 MHz, +80 dB peak at 2440 MHz).
      • LTE (700–2700 MHz, +90 dB peak at 1800 MHz).
      • 5G NR (3500–3700 MHz, +85 dB peak at 3600 MHz).
      • Zigbee (2400–2450 MHz, +75 dB peak at 2425 MHz).
    • Adds Gaussian noise (±10 dB) to the noise floor.
    • Generates random phases (0 to 2π) for each frequency bin.
  • Window Application:
    • Applies the selected window function to the amplitude data to reduce spectral leakage.
    • Supports Hanning, Blackman-Harris, Kaiser, Flat-Top, and Gaussian windows, each with specific coefficients or parameters (e.g., Kaiser uses a Bessel function with β=8.6).
  • Demodulation:
    • If a demodulation type is selected, applies the Demodulator to modify amplitudes based on phases (see Demodulator section).
  • Analysis Mode:
    • In Swept-Tuned mode, attenuates amplitudes based on sweep speed (0.8 / sweepSpeed).
  • Data Storage:
    • Updates a SpectrumData object with amplitudes, phases, and frequency range.

Spectrum Visualization

• Purpose: Renders the signal spectrum or persistence display on a canvas.
• Key Features:
  • Display modes: Spectrum (real-time plot) or Persistence (intensity-based history).
  • Adjustable dynamic range (default 160 dB).
  • Logarithmic or linear frequency scale.
  • Channel markers for bandwidth and count.
  • Grid and labels for frequency and amplitude.
• Logic:
  • Spectrum Mode:
    • Clears the canvas with a black background.
    • Plots amplitudes as a yellow line, scaled to canvas dimensions.
    • Supports logarithmic frequency scaling if enabled.
    • Draws red markers for channel boundaries based on center frequency, bandwidth, and channel count.
    • Adds a grid (10x10) with frequency (Hz) and amplitude (dBm) labels.
  • Persistence Mode:
    • Maintains a 400-frame buffer of amplitude histories.
    • Fades older data (0.95 decay) and updates with new amplitudes.
    • Colors pixels green based on intensity (0–255).
  • Metrics:
    • getChannelPower(): Calculates average power (dBm) within the channel bandwidth around the center frequency.
    • getACPR(): Computes the power ratio (dB) between the main channel and adjacent channels (up to 3x bandwidth).

Demodulation Graphics

• Purpose: Displays the demodulated signal waveform.
• Logic:
  • Clears the canvas with a black background.
  • Retrieves amplitude data from SignalProcessor (post-demodulation).
  • Plots the waveform as a yellow line, centered vertically, with amplitude scaled to ±400 units.
  • Draws a dark gray centerline for reference.
  • Updates in sync with the AnimationTimer.

Demodulation

• Purpose: Applies demodulation to the signal based on the selected type.
• Supported Types:
  • AM: Multiplies amplitude by cos(phase).
  • FM: Computes phase differences ((phase[i] - phase[i-1]) / 2π).
  • PM: Normalizes phases (phase / 2π).
  • QAM: Combines in-phase (I = amplitude * cos(phase)) and quadrature (Q = amplitude * sin(phase)) components as sqrt(I² + Q²).
  • PSK: Quantizes phases to nearest multiples of π/4.
  • OFDM: Applies AM with a random phase offset (±π/8).
• Logic:
  • Copies input amplitudes to a result array.
  • Modifies the result based on the demodulation type using amplitude and phase data.
  • Returns the demodulated amplitudes.

Signal Classification

• Purpose: Identifies the signal type based on spectral characteristics.
• Logic:
  • Analyzes the SpectrumData amplitudes to find the peak amplitude and corresponding frequency.
  • Counts peaks with the same amplitude to adjust confidence (fewer peaks → 90%, more → 70%).
  • Classifies based on frequency and amplitude thresholds:
    • Bluetooth: 2400–2480 MHz, >-100 dBm.
    • Wi-Fi: 100–200 Hz, >-80 dBm.
    • LTE: 700–2700 MHz, >-90 dBm.
    • 5G NR: 3500–3700 MHz, >-95 dBm.
    • Zigbee: 2400–2450 MHz, >-105 dBm.
    • Unknown: Default, 50% confidence.
  • Returns a string with the signal type and confidence percentage.

Data Storage

• Purpose: Stores and provides access to spectral data.
• Logic:
  • Holds arrays for amplitudes and phases (size 16,384).
  • Stores min and max frequencies.
  • Provides getters for data access and an update method to refresh data

UI Layout

• Purpose: Defines the UI structure using JavaFX components.
• Structure:
  • A BorderPane with a top Label ("Spectrum Analyzer").
  • A center SplitPane containing:
    • Left Panel: Control panel with sliders, ComboBoxes, TextFields, ToggleButton, and export Button, organized in TitledPane sections (Frequency, Analysis Mode, etc.).
    • Right Panel: Canvas containers for spectrum and demodulation visualizations, plus metric labels (channel power, ACPR, signal type, window info).
  • Styled via style.css for a dark theme with yellow accents.

Styling

• Purpose: Defines the visual appearance of the UI.
• Key Styles:
  • Black background for most components.
  • Yellow text and accents for labels, buttons, and sliders.
  • Dark gray for tracks, borders, and backgrounds of interactive elements.
  • Courier New font, 12px size.
  • Custom styling for sliders, ComboBoxes, ToggleButtons, and scrollbars.

---

---