Vector Signal Analyzer Implemented as a Synthetic Instrument

Abstract

Synthetic instruments (SIs) use the substantial signal processing assets of a field-programmable gate array (FPGA) to perform the multiple tasks of targeted digital signal processing (DSP)-based instruments. The topic of this paper is vector signal analysis from which time-dependent amplitude and phase is extracted from the input time signal. With access to the time-varying amplitude-phase profiles of the input signal, the vector signal analyzer can present many of the quality measures of a modulation process. These include estimates of undesired attributes such as modulator distortion, phase noise, clock jitter, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> imbalance, intersymbol interference, and others. This is where the SI is asked to become a smart software-defined radio (SDR), performing all the tasks of a DSP radio receiver and reporting small variations between the observed modulated signal parameters and those of an ideal modulated signal. Various quality measures (e.g., the size of errors) have value in quantifying and probing performance boundaries of communication systems.