Script Files and Function Files Implementation for Modulation, Demodulation, and SNR Calculation

In signal processing, script files and function files represent two fundamental code organization approaches. Script files are ideal for rapid prototyping and visualization tasks, while function files support modular development with better reusability and debugging capabilities. Both formats can be effectively employed in modulation-demodulation systems for signal generation, modulation, demodulation, and signal-to-noise ratio (SNR) calculations. The modulation process typically involves converting baseband signals to high-frequency signals suitable for channel transmission. Common modulation techniques include AM (Amplitude Modulation), FM (Frequency Modulation), and digital modulation schemes like QPSK (Quadrature Phase Shift Keying). In code implementation, modulation functions often accept parameters such as carrier frequency, modulation index, and input data stream, returning the modulated signal array. Demodulation performs the reverse operation, reconstructing original information from received signals using techniques like envelope detection (for AM) or phase-locked loops (for FM). SNR calculation serves as a critical performance metric for communication systems, quantitatively assessing signal quality through power ratio comparisons between desired signals and noise components. A typical SNR function implementation would calculate signal power using mean square values and noise power through variance measurements, often expressed in decibels (dB) using the formula: SNR_dB = 10*log10(Ps/Pn). To address limitations in Empirical Mode Decomposition (EMD) methods, such as mode mixing and endpoint effects, signal preprocessing can incorporate complementary techniques like wavelet transforms or adaptive filtering. Script files enable quick validation of algorithm effectiveness through visual plots and intermediate result checks, while function files can encapsulate these enhanced methods into reusable modules for integration into larger systems. For practical implementation, developers should first debug core logic (such as modulation-demodulation chain correctness) using script files with sample data and visualization commands. Subsequently, refactoring into function files with clear input/output parameters improves code maintainability. SNR calculation routines are particularly suitable for function encapsulation, allowing standardized invocation across different scenarios with configurable parameters for signal and noise segments.