Assessment of Measurement Error when Using the Laser Spectrum Analyzers

• Main Authors: A. A. Titov, V. K. Garipov, M. A. Kostromin
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Nauka i Obrazovanie
• Subjects: error; measurement; laser spectrum analyzers; radio signals; interferometers
• Online Access: http://technomag.edu.ru/jour/article/view/85
• ISSN: 1994-0408

The article dwells on assessment of measurement errors when using the laser spectrum analyzers. It presents the analysis results to show that it is possible to carry out a spectral analysis of both amplitudes and phases of frequency components of signals and to analyze a changing phase of frequency components of radio signals using interferential methods of measurements. It is found that the interferometers with Mach-Zehnder arrangement are most widely used for measurement of signal phase. A possibility to increase resolution when using the combined method as compared to the other considered methods is shown since with its application spatial integration is performed over one coordinate while time integration is done over the other coordinate that is reached by the orthogonal arrangement of modulators relative each other. The article defines a drawback of this method. It is complicatedness and low-speed because of integrator that disables measurement of spectral components of a radio pulse if its width is less than a temporary aperture. There is a proposal to create an advanced option of the spectrum analyzer in which phase is determined through the signal processing. The article presents resolution when using such a spectrum analyzer. It also reviews the possible options for creating devices to measure the phase components of a spectrum depending on the methods applied to measure a phase. The analysis has shown that for phase measurement a time-pulse method is the most perspective. It is found that the known circuits of digital phase-meters using this method cannot be directly used in spectrum analyzers as they are designed for measurement of the phase only of one signal frequency. In this regard a number of circuits were developed to measure the amplitude and phase of frequency components of the radio signal. It is shown that the perspective option of creating a spectrum analyzer is device in which the phase is determined through the signal processing. The article presents a function diagram of such spectrum analyzer and a time diagram of its operation.