Whitepaper
Spectrum and Signal Analyzer Measurements and Noise
This whitepaper details noise measurements and analysis techniques using spectrum and signal analyzers, particularly focusing on signals relevant to digital communications like CDMA and TDMA. It begins by examining the statistical characteristics of baseband and bandpassed noise—specifically Gaussian and Rayleigh distributions—and how these impact measurement accuracy when using envelope detection in linear scales (introducing a 1.05dB underestimation). The paper then explores methods for accurate power measurements, including logarithmic processing and averaging techniques like swept vs. FFT analysis and zero-span modes. Finally, it addresses compensation strategies for instrumentation noise via Noise Floor Extension (NFE) and highlights the advantages of log scales for CW signal measurements with Keysight X-Series analyzers.