Spectrum analyzer

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

Characteristics of External Loop Sensor Located Near Bushing on Partial Discharge Induced Electromagnetic Wave Measurement

Abstract: For transmitting a huge electrical energy, high voltage transmission systems are commonly operated. Due to high reliability and less space required, gas insulated substation (GIS) are widely used. In a defect experienced GIS, partial discharge (PD) usually takes place. Partial discharge (PD) monitoring technique using UHF method becomes more popular because of its higher signal to noise (S/N) ratio. Amongst novel sensors, loop sensor could be a candidate for PD detector to measure UHF signal emitted from PD source. This paper presents the experiment results on characteristics of loop sensors. The characteristics of three loop sensors with varying diameter were examined using a spectrum analyzer and a network analyzer to obtain frequency characteristic and optimum operating frequency (S11) parameter, respectively. Then, PD experiment was conducted on 66kV GIS model having floating electrode and free metallic particles as its PD source. The loop sensors were placed far external to GIS bushing to measure leaked PD signal from it. The influences of the sensor diameter and the sensor distance from GIS bushing on PD detection sensitivity were also examined. Based on IEC-60270 standard measurement, the highest sensitivity of 30 pC was obtained from this investigation. The result suggests that higher sensitivity could be achieved with proper shielding and suitable filter design against external noise.

Power Measurement in Digital Wireless Communication Systems Through

Abstract: Power measurement in digital wireless communica- tion systems often suffers from poor repeatability, usually ac- companied by a low accuracy. To face the problem, the use of parametric spectral estimators is investigated in this paper. In par- ticular, a new method is proposed, which first estimates the power spectral density (PSD) of the analyzed signal through Burg's so- lution, and then evaluates the power by applying straightforward measurement algorithms to the estimated PSD. The results of a number of experiments, carried out on both laboratory and actual signals peculiar to digital wireless communication systems, assess the efficacy and reliability of the method. Moreover, a comparison of the achieved performance to that offered by an alternative measurement solution, already proposed by the authors and based on nonparametric PSD estimation, shows that the method allows for a significant reduction of measurement time, while exhibiting the same repeatability. Index Terms—Channel power measurement, digital video broadcasting-satellite (DVB-S), occupied bandwidth measure- ment, performance spectrum analyzers, power-spectral-density (PSD) estimation, spread-spectrum systems, universal mobile tele- communication system (UMTS), vector signal analyzers (VSAs).

High-Resolution Dielectric Sensor Based on Injection-Locked Oscillators

Abstract: The structure of a high-resolution microwave material sensor is presented based on the injection locking phenomenon. For a sample under test, the variation of center frequency and lock range of the oscillator with respect to a reference sample are measured to indicate the resonance frequency and quality factor of the resonator. A low power level and low phase noise injection locking can significantly reduce the lock range of the oscillator. Therefore, even small variations in the loop filter of the oscillator change the response and can be determined with a high sensitivity. The unknown sample is characterized based on the measured center frequency and quality factor of the resonator. An output power control (OPC) system increases the dynamic range of the sensor with respect to the dielectric constant of samples. Moreover, a method of material detection in the microwave frequency is proposed based on data from the OPC to eliminate the frequency analyzer from the system for Internet of Things (IoT) applications. As an example for validation, a 1-GHz sensor is fabricated and the measurement results are presented.

Non-invasive blood constituent measuring instrument and measuring method

Abstract: A non-invasive blood constituents measuring instrument measures blood constituent values including blood glucose concentration in a living body non-invasively. The instrument is composed of a light source 11 to irradiate a light containing plural wavelengths to a living body 13 , a light receiver 14 to detect the light transmitted through a living body or reflected and scattered thereon, a spectrum analyzer 15 to analyze the light transmitted through the living body or reflected thereon at different times, a subtraction processor 18 to generate spectrum subtraction from the spectrum of the light at the different times measured by the spectrum analyzer 15 , and a blood glucose concentration predictor 21 into which the output data of the subtraction processor 18 are input and which outputs a blood constituent value.

Device and method for frequency interpolation and recording medium

Abstract: PROBLEM TO BE SOLVED: To provide a frequency interpolation device, etc., which restores a modulated wave obtained by using a band-limited signal of a source signal to a signal close to the source signal or restores an audio signal with high sound quality. SOLUTION: An analyzer 1 converts a PCM signal into the spectrum of the PCM signal. A frequency interpolation processing part 2 specifies the combination having the highest correlation of a spectrum distribution among combinations of a reference band including the band of the highest frequency among bands obtained by equally dividing the spectrum into several and other bands when one is standardized. An interpolation band addition part 3 estimates the envelope of the PCM signal, scales the spectrum of the same distribution as the spectrum distribution in the reference band included in the combination specified by the frequency interpolation processing part 2 along the function of the envelope, and adds the result to a frequency side higher than the reference band. A synthesizer 4 generates a signal giving the spectrum after the interpolation band addition part 3 performs the addition. COPYRIGHT: (C)2001,JPO