Spectrum analyzer

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

Method of and apparatus for measuring optical frequency variations

Abstract: Herein is disclosed a method of and apparatus for measuring optical frequency variations wherein linearly-polarized incident light generated by a tunable laser or the like is delivered to a passive resonant cavity incorporating a linear polarizer such as a Brewster plate so that the reflected light acquires a frequency-dependent elliptical polarization which can be detected by a simple polarization analyzer providing a signal correlated with the frequency variation of the laser. Such signal can be utilized as a feedback error signal to stabilize the laser frequency, or to adjust the cavity resonance. If the cavity is tunable, tuning thereof will in turn provide a precision method for tuning of the laser itself.

A CMOS-Compatible Spectrum Analyzer for Cognitive Radio Exploiting Crosscorrelation to Improve Linearity and Noise Performance

Abstract: A spectrum analyzer requires a high linearity to handle strong signals, and at the same time a low NF to enable detection of much weaker signals. This is not only important for lab equipment, but also for the spectrum sensing part of cognitive radio, where low cost and integration is at a premium. Often there is a trade-off between linearity and noise: improving one degrades the other. Crosscorrelation can break this trade-off by reducing noise at the expense of measurement time. An existing RF frontend in CMOS-technology with IIP3 = +11 dBm and NF = 5.5 dB is duplicated and attenuators are put in front to increase linearity to IIP3 = +24 dBm. The attenuation degrades NF, but by using crosscorrelation of the outputs of the two frontends, the effective NF is reduced to around 5 dB. In total, this results in a spurious-free dynamic range of 88 dB in 1 MHz resolution bandwidth.

Network implementation of spectrum analysis

Abstract: Access devices may receive signals over a network and calculate a frequency spectrum of the received signals. An analyzer system may collect the frequency spectrum data from multiple access devices, and based on the collected data, detect, identify, and locate sources of anomalies in a communication network.

16-channel (1- to 16-GHz) microwave spectrum analyzer device based on a phased array of GaAs/AlGaAs electro-optic waveguide delay lines

Abstract: We demonstrate a sixteen channel, GaAs/AlGaAs staring spectrum analyzer device based on a phased-array of sixteen electro-optic waveguide delay lines. The device is effectively a high resolution version of the widely reported optical wavelength division multiplexer phased-array devices, using electro-optic waveguides to adjust the optical phases across the array. The device comprises: a 1- to-16 way multimode interference coupler; 16 electro-optic phase controllers; 16 folded waveguide delay lines, from 0 to 1 nanosecond in equal steps; and a waveguide phased array output. By making use of novel waveguide and corner designs we demonstrate the device as a spectrum analyzer, the RF signal to be analyzed was superimposed on an optical carrier using a GaAs/AlGaAs electro-optic waveguide push-pull Mach Zehnder interferometer, and the intensity modulated light was then passed through the phased-array chip. The spectrum of the RF input signal was displayed in the far field of the phased-array as diffraction lines on either side of the main diffraction lines. By biasing the modulator to extinction, the CW carrier could be removed from the far field diffraction pattern so that only the RF spectrum was displayed. In this presentation we describe the device design, fabrication and testing including measurements of the dynamic range and resolution.

Compression rate analyzer

Abstract: A system and method for monitoring the performance and condition of various cylinder components of internal combustion engines through the provision of a transducer for detecting the time-rate-of-change of pressure within the cylinder during normal operation of the engine and a circuit for processing and quantizing the transducer signal to develop a numerical indication of pressure changes within the cylinders. The system also includes a tachometer circuit and display apparatus as well as an optional memory and processor to facilitate a comparative analysis of the various cylinders at varying speeds.