Spectrum analyzer

About: Spectrum analyzer is a research topic. Over the lifetime, 12217 publications have been published within this topic receiving 101851 citations.

Frequency modulation-polarization spectroscopy method and device for detecting spectral features

Abstract: A method and device for detecting dichroic and/or birefringent narrow spectral features in a sample is described The method includes the steps of providing a beam of light having an optical frequency bandwidth which is narrow compared to the width of the narrow spectral feature and having a center frequency ωc which lies near the narrow spectral feature, polarization phase modulating a beam of light with a single RF frequency to provide a pure FM spectrum having upper and lower sidebands in which either the carrier and sidebands have been polarized with respect to one another, exposing the sample containing the narrow spectral feature to the polarized modulated light so that the FM sidebands probe the narrow spectral feature, polarization analyzing and then photodetecting the light emerging from the sample to detect a RF beat at the specific RF frequency used for the polarization phase modulation, and electronically monitoring the amplitude of the RF beat signal to indicate the strength of the narrow spectral feature The device includes a polarization phase modulator and a polarization analyzer positioned on opposite sides of the sample In a preferred embodiment the polarization phase modulator produces a frequency modulated optical spectrum with the sidebands polarized precisely orthogonal to the carrier

A Waveform Analyzer Applied to the Human EEG

Abstract: This paper presents an approach to signal waveform analysis in the frequency range of 1 to 50 Hz. The technique is applicable to any waveform which is a single-valued function of time with continuous derivatives. The main application of this system has been on the human EEG. The analyzer, to be described, performs its analysis in the time domain and abstracts wave shape information from the original wave and from the successive mathematical derivatives of that wave. The output from this analyzer consists of six analog descriptors of the input EEG wave. These descriptors are basic amplitude and basic frequency of the original input wave, amplitude and frequency of the first derivative of the input wave, and amplitude and frequency of the second derivative of the input wave.

Single‐Channel Analyzer

Abstract: A single‐channel analyzer has been built for measuring the pulse spectrum from proportional and scintillation counters; it counts the number of pulses whose heights lie between E and E+ΔE. The interval ΔE or ``window width'' is constant within ±1.2 percent for all values of E between zero and ninety volts. Curves are presented which show that the analyzer performs satisfactorily on the random distribution of pulse amplitudes obtained from counters.

Spectrum analyzers today and tomorrow: part 1 towards filterbanks-enabled real-time spectrum analysis

Abstract: This is Part 1 of a two-part article on spectrum analyzer technology and the future capabilities enabled by introducing filterbanks. A spectrum analyzer (SA) is the primary tool for studying the spectral composition of many electrical, acoustic or optical waveforms. It displays a power spectrum over a given frequency range, changing the display as the properties of the signal change. Today, it is an essential element of the engineer's toolbox. In this part, we will start by reviewing SA architectures in an historical perspective. The architectures and working principles of swept based and Fast Fourier Transform (FFT)-based SAs are discussed. Then, we zoom in on the so-called Real-Time Spectrum Analyzers (RTSA) and discuss the more significant performance criteria as a function of the measurement problem at hand. In the last section, we discuss several applications made possible by RTSA. The extension of RTSA with filterbanks is the main topic of Part 2 of this article which will appear in the December 2013 issue of the IEEE Instrumentation and Measurement Magazine.

Phase-noise measurement with compensation for phase noise contributed by spectrum analyzer

Abstract: A method and apparatus compensates for phase noise added by a spectrum analyzer from phase noise measurements of a signal under test (SUT) taken by the spectrum analyzer. The method comprises the steps of measuring the phase noise of the SUT, determining the added phase noise of the spectrum analyzer, and applying a mathematical correction to the measured phase noise. A spectrum analyzer apparatus that compensates for added phase noise comprises a controller portion, a memory portion, a signal conversion and detection portion, and a compensation algorithm stored in the memory portion. A system that compensates for added phase noise comprises a controller having a control algorithm and a spectrum analyzer. The compensation and control algorithms are computer programs that implement the method of the present invention.