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Showing papers on "Spectrum analyzer published in 2012"


Patent
17 Apr 2012
TL;DR: In this paper, a blood analysis system functions as a non-invasive blood parameter analyzer when a monitor is coupled with an optical sensor and as an invasive blood sample analyzer if the monitor was coupled with a blood analyzer adapter.
Abstract: A blood analysis system functions as a non-invasive blood parameter analyzer when a monitor is coupled with an optical sensor and as an invasive blood sample analyzer when the monitor is coupled with a blood analysis adapter. The blood analysis adapter has a transmitting assembly and a receiving assembly in electrical communications with the adapter connector so as to receive emitter signals for driving emitters within the transmitting assembly and so as to transmit a detector signal for responding to at least one detector in the receiving assembly. A cuvette containing a blood sample is irradiated with multiple wavelength light from the emitters, the detector responds to the multiple wavelength light after attenuation by the blood sample, and the monitor analyzes the blood sample according to the detector signal.

135 citations


Journal ArticleDOI
TL;DR: A 16-channel, mixed-signal CMOS DNA analyzer that utilizes frequency response analysis (FRA) to extract the real and imaginary impedance components of the biosensor resulting in minimal area and power consumption is presented.
Abstract: We present a 16-channel, mixed-signal CMOS DNA analyzer that utilizes frequency response analysis (FRA) to extract the real and imaginary impedance components of the biosensor. Two computationally intensive operations, the multiplication and integration required by the FRA algorithm, are performed by an in-channel dual-slope multiplying ADC in the mixed-signal domain resulting in minimal area and power consumption. Multiplication of the input current by a digital coefficient is implemented by modulating the counter-controlled duration of the charging phase of the ADC. Integration is implemented by accumulating output digital bits in the ADC counter over multiple input samples. The 1.05 × 1.6 mm prototype fabricated in a 0.13 μm standard CMOS technology has been validated in prostate cancer DNA detection. Each channel occupies an area of only 0.06 mm2 and consumes 42 μW of power from a 1.2 V supply.

117 citations


Journal ArticleDOI
TL;DR: The capabilities and performance for this new state-of-the-art neutron spectrometer at the NIST Center for Neutron Research (NCNR) are discussed.
Abstract: The new thermal triple-axis spectrometer at the NIST Center for Neutron Research (NCNR) is located at the BT-7 beam port. The 165 mm diameter reactor beam is equipped with a selection of Soller collimators, beam-limiters, and a pyrolytic graphite (PG) filter to tailor the beam for the dual 20×20 cm(2) double-focusing monochromator system that provides monochromatic fluxes exceeding 10(8) n/cm(2)/s onto the sample. The two monochromators installed are PG(002) and Cu(220), which provide incident energies from 5 meV to above 500 meV. The computer controlled analyzer system offers six standard modes of operation, including a diffraction detector, a position-sensitive detector (PSD) in diffraction mode, horizontal energy focusing analyzer with detector, a Q-E mode employing a flat analyzer and PSD, a constant-E mode with the analyzer crystal system and PSD, and a conventional mode with a selection of Soller collimators and detector. Additional configurations for specific measurement needs are also available. This paper discusses the capabilities and performance for this new state-of-the-art neutron spectrometer.

90 citations


Patent
21 Feb 2012
TL;DR: In this article, a terahertz wave detector is used for real-time spectroscopy, where the timing at which a probe light is irradiated on an optical switching device in the detector is vibratingly varied by driving a movable reflector in a variable optical delay device at a predetermined vibration frequency.
Abstract: A terahertz wave detector is for detecting a terahertz wave which is emitted from a terahertz wave generator and which is transmitted through a sample. The timing, at which a probe light is irradiated on an optical switching device in the terahertz wave detector, is vibratingly varied by driving a movable reflector in a variable optical delay device at a predetermined vibration frequency. The resultant detection signal generated thereby and changing periodically and vibratingly is subjected to frequency analysis by a spectrum analyzer in a spectroscopic processor. The detection signal has the same temporal waveform as that of the terahertz wave and subjected to scale conversion. Therefore, the frequency analysis of the detection signal enables frequency measurement of a terahertz wave in real time. As a result, real-time spectroscopy is possible, and the device configuration is simplified.

88 citations


Journal ArticleDOI
TL;DR: High-resolution, wide-bandwidth optical spectrum analysis is essential to the measuring and monitoring of advanced optical, millimeter-wave, and terahertz communication systems, sensing applications and device characterization.
Abstract: High-resolution, wide-bandwidth optical spectrum analysis is essential to the measuring and monitoring of advanced optical, millimeter-wave, and terahertz communication systems, sensing applications and device characterization. One category of high-resolution spectrum analyzers reconstructs the power spectral density of a signal under test by scanning a Brillouin gain line across its spectral extent. In this work, we enhance both the resolution and the optical rejection ratio of such Brillouin-based spectrometers using a combination of two techniques. First, two Brillouin loss lines are superimposed upon a central Brillouin gain to reduce its bandwidth. Second, the vector attributes of stimulated Brillouin scattering amplification in standard, weakly birefringent fibers are used to change the signal state of polarization, and a judiciously aligned output polarizer discriminates between amplified and un-amplified spectral contents. A frequency resolution of 3 MHz, or eight orders of magnitude below the central optical frequency, is experimentally demonstrated. In addition, a weak spectral component is resolved in the presence of a strong adjacent signal, which is 30 dB stronger and detuned by only 60 MHz. The measurement method involves low-bandwidth direct detection, and does not require heterodyne beating. The measurement range of the proposed method is scalable to cover the C + L bands, depending on the tunable pump source. The accuracy of the measurements requires that the pump frequencies are well calibrated.

64 citations


Patent
17 Oct 2012
TL;DR: In this paper, the authors present a spectrum density graph that maps a range of detected densities of detected frequency signals to a corresponding range of color hues, and a waterfall spectrum graph displaying the corresponding detected density using the same color mapping of the detected range of densities.
Abstract: A computer program product stored on a non-transitory computer readable medium usable with a programmable computer, the computer program product having computer-readable code embodied therein for displaying data in a graphical format, the computer-readable code includes, but is not limited to, instructions for mapping a range of detected densities of detected frequency signals to a corresponding range of color hues, generating a spectrum density graph displaying the detected frequency signals and corresponding densities as represented by the mapped corresponding range of color hues, and generating a waterfall spectrum graph displaying the corresponding detected densities utilizing the same color mapping of the detected range of densities of detected frequency signals as utilized by the generated spectrum density graph, thereby providing a density color match between data points on the spectrum density graph and the waterfall spectrum graph

63 citations


Journal ArticleDOI
TL;DR: In this paper, a commercial retarding field analyzer is used to measure the time-averaged ion energy distributions of impacting ions at the powered electrode in a 13.56 MHz driven, capacitively coupled, parallel plate discharge operated at low pressure.
Abstract: A commercial retarding field analyzer is used to measure the time-averaged ion energy distributions of impacting ions at the powered electrode in a 13.56 MHz driven, capacitively coupled, parallel plate discharge operated at low pressure. The study is carried out in argon discharges at 10 mTorr where the sheaths are assumed to be collisionless. The analyzer is mounted flush with the powered electrode surface where the impacting ion and electron energy distributions are measured for a range of discharge powers. A circuit model of the discharge, in combination with analytical solutions for the ion energy distribution in radio-frequency sheaths, is used to calculate other important plasma parameters from the measured energy distributions. Radio-frequency compensated Langmuir probe measurements provide a comparison with the retarding field analyzer data. The time-resolved capability of the retarding field analyzer is also demonstrated in a separate pulsed dc magnetron reactor. The analyzer is mounted on the floating substrate holder and ion energy distributions of the impinging ions on a growing film, with 100 ns time resolution, are measured through a pulse period of applied magnetron power, which are crucial for the control of the microstructure and properties of the deposited films.

61 citations


Journal ArticleDOI
TL;DR: In this article, a retarding field energy analyzer is used to characterize an asymmetric, 13.56MHz driven, capacitively coupled, parallel plate discharge operated at low pressure.
Abstract: A retarding field energy analyzer is used to characterize an asymmetric, 13.56 MHz driven, capacitively coupled, parallel plate discharge operated at low pressure. The characterization is carried out in argon discharges at 10 and 20 mTorr where the sheaths are assumed to be collisionless. The analyzer is set in the powered electrode where the impacting ion and electron energy distributions are measured for a range of discharge powers. A circuit model of the discharge is used to infer important electrical parameters from the measured energy distributions, including electrode excitation voltages, plasma potential and sheath potentials. Analytical models of the ion energy distribution in a radio-frequency sheath are used to determine plasma parameters such as sheath width, ion transit time, electron temperature and ion flux. A radio-frequency compensated Langmuir probe is used for comparison with the retarding field analyzer measurements.

53 citations


Journal ArticleDOI
TL;DR: The Angle Resolved Time Of Flight electron energy analyzer (ARTOF 10k) as discussed by the authors is a novel type of photoemission detector, which enables electronic band structure determination under measurement uncertainties.

50 citations


Journal ArticleDOI
TL;DR: The design and implementation of a virtual multifunction PQ analyzer based on the adaptive linear neural network is discussed and the main advantages are the simplification and integration for the harmonic/interharmonic analyzer, flickermeter, and voltage event identifier by adopting the same computational mechanism.
Abstract: Monitoring of electrical quantities is an important task for the evaluation of power quality (PQ). However, analysis methods for PQ disturbances are quite different. This circumstance would make the design of a multifunction PQ-measuring instrument difficult. In this paper, the design and implementation of a virtual multifunction PQ analyzer based on the adaptive linear neural network are discussed. The main advantages of the realized analyzer are the simplification and integration for the harmonic/interharmonic analyzer, flickermeter, and voltage event identifier by adopting the same computational mechanism. Finally, some tests are made to verify the performance of the proposed virtual multifunction analyzer.

49 citations


Patent
17 May 2012
TL;DR: In this paper, an accelerometer, magnetometer/gyroscope unit, and processor unit are mounted in a handle at the grip end of a golf club to calculate the estimated carrying distance of a ball when struck by a golf ball.
Abstract: A golf club including a swing analyzer includes an accelerometer that measures acceleration in three directions, a magnetometer/gyroscope unit, a processor unit that converts the measured acceleration and golf club movement during a non-ball-striking or ball-striking swing into an estimated carrying distance of a golf ball when struck by the golf club based on swing position and a type of the golf club, and a display that displays the estimated carrying distance as a function of swing position to the golfer. The accelerometer, magnetometer/gyroscope unit, and processor unit may be mounted in a handle at a grip end of the golf club. The estimated carrying distance calculation may be performed at a unit separate from the golf club and capable of performing this calculation for several golf clubs with which it communicates via cooperating communications unit.

Journal ArticleDOI
TL;DR: In this article, a method to determine the four Stokes parameters of each spectral component in a broadband terahertz (THz) pulse by using a continuously rotating analyzer and a standard THz-TDS instrument is presented.
Abstract: We report a method to determine the four Stokes parameters of each spectral component in a broadband terahertz (THz) pulse by using a continuously rotating analyzer and a standard THz time domain spectroscopy (THz-TDS) instrument. A complete characterization of the polarization state at each frequency is obtained through a single time-domain measurement. Our method requires no specialized THz emitters or detectors; it is, therefore, perfectly general and suitable for any existing THz-TDS apparatus.

Journal ArticleDOI
TL;DR: CooVar is an easy-to-use and lightweight variant annotation tool that considers the combined impact of GVs on protein-coding transcripts, generating biologically more accurate annotations.
Abstract: Background: Evaluating the impact of genomic variations (GV) on protein-coding transcripts is an important step in identifying variants of functional significance. Currently available programs for variant annotation depend on external databases or annotate multiple variants affecting the same transcript independently, which limits program use to organisms available in these databases or results in potentially incorrect or incomplete annotations. Findings: We have developed CooVar (Co-occurring Variant Analyzer), a database-independent program for assessing the impact of GVs on protein-coding transcripts. CooVar takes GVs, reference genome sequence, and protein-coding exons as input and provides annotated GVs and transcripts as output. Other than similar programs, CooVar considers the combined impact of all GVs affecting the same transcript, generating biologically more accurate annotations. CooVar is operated from the command-line and supports standard file formats VCF, GFF/GTF, and GVF, which makes it easy to integrate into existing computational pipelines. We have extensively tested CooVar on worm and human data sets and demonstrate that it generates correct annotations in only a short amount of time. Conclusions: CooVar is an easy-to-use and lightweight variant annotation tool that considers the combined impact of GVs on protein-coding transcripts. CooVar is freely available at http://genome.sfu.ca/projects/coovar/.

Proceedings ArticleDOI
01 Oct 2012
TL;DR: Results suggest enough energy is available to support a low duty cycle wireless sensor node system, and an average RF power of 11nW is observed 10m away from a typical Wi-Fi access point in an office environment, suggesting the possibility of low Duty cycle, wirelessly powered sensing and communication using a Bluetooth Low Energy (BLE) or another ultra low power uplink.
Abstract: We present a new system for measuring ambient RF energy in the 2.4GHz ISM band. This apparatus is intended to establish the feasibility of harvesting ambient RF energy to power emerging ultra-low-power sensors and microcontrollers. We simultaneously acquire RF measurements from a spatial and polarization diversity antenna system, with both a spectrum analyzer (frequency-selective but slow), and a log amp (wideband but fast), explain key tradeoffs in the measurement configuration, and present a post-processing algorithm which provides a reliable characterization of the RF energy available in the 2.4GHz ISM band. Preliminary results suggest enough energy is available to support a low duty cycle wireless sensor node system. An average RF power of 11nW is observed 10m away from a typical Wi-Fi access point in an office environment, suggesting the possibility of low duty cycle, wirelessly powered sensing and communication using a Bluetooth Low Energy (BLE) or another ultra low power uplink.

Journal ArticleDOI
TL;DR: In this article, two methods were described to estimate interference in the measurements of infrared photoacoustic multi-gas analyzer (PAMGA), one is IR spectroscopic analysis (IRSA) and the other is mathematical simulation.
Abstract: Two methods were described to estimate interference in the measurements of infrared (IR) photoacoustic multi-gas analyzer (PAMGA). One is IR spectroscopic analysis (IRSA) and the other is mathematical simulation. An Innova 1412 analyzer (AirTech Instruments, Ballerup, Denmark) with two different filter configurations was used to provide examples that demonstrate the two methods. The filter configuration in Example #1 consists of methane (CH4), methanol (MeOH), ethanol (EtOH), nitrous oxide (N2O), carbon dioxide (CO2), and water vapor (H2O), and in Example #2 of ammonia (NH3), MeOH, EtOH, N2O, CO2, and H2O. The interferences of NH3 as a non-target gas in Example #1 were measured to validate the two methods. The interferences of H2O and NH3 as target gases in Example #2 were also measured to evaluate the analyzer's internal cross compensation algorithm. Both simulation and experimental results showed that the interference between the target gases could be eliminated by the internal cross compensation algorithm. But the interferences of non-target gases on target gases could not be addressed by the internal cross compensation, while they could be assessed by the IRSA and mathematical simulation methods. If the IR spectrum of a non-target gas overlaps with that of target gas A at filter A, it could affect not only gas A (primary interference), but

Patent
31 Oct 2012
TL;DR: In this article, a COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time domain analyzer which comprises a narrow-linewidth laser, two couplings, a microwave signal source, an electro-optic modulator, an isolator, a long distance sensing optical fiber, an optical circulator, a 3 db coupling, a pulse modulator.
Abstract: The invention discloses a COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer which comprises a narrow-linewidth laser, two couplings, a microwave signal source, an electro-optic modulator, an isolator, a long-distance sensing optical fiber, an optical circulator, a 3 db coupling, a pulse modulator, an Er-doped fiber amplifier, a scrambler, a pulse signal generator, a balancing photoelectric detector, an electrical frequency spectrum analyzer, a data processing module and an acousto-optic modulator According to the invention, the signal-to-noise ratio of BOTDA (brilouin optical time domain analysis) is improved by using a coherent detection method, a non-local effect of a BOTDA system is reduced in a double-sideband detection mode, and the sensing distance is more than 70 km under the condition of no light amplification such as raman; and according to the invention, the COTDR is fused to a coherent detection based BOTDA system, and the system can run in a breakpoint testing mode, so that the defect that the traditional BOTDA can not run when a sensing fiber has breakpoints and can not carry out positioning on breakpoints is effectively overcome, thereby enhancing the adaptability and practicability of the sensing system

Patent
24 Sep 2012
TL;DR: In this article, a method for determining a distance to a source of passive intermodulation (PIM) in a radio frequency (RF) transmit/receive system comprises a two-step process.
Abstract: An embodiment of a method in accordance with the present invention for determining a distance to a source of passive intermodulation (PIM) in a radio frequency (RF) transmit/receive system comprises a two step process. As a first step, a first and second signal with frequencies in a transmit band are generated at a first power and a third order harmonic signal generated by a source of PIM within the system is obtained in the receive band. If the magnitude of the PIM exceeds a noise threshold, a second step is performed. The second step includes generating a third and fourth signal at a second power higher than the first power to obtain a higher order harmonic signal generated by the source of PIM. The PIM magnitude and a distance to the source of the PIM are calculated using the higher order harmonic signal.

Patent
08 Aug 2012
TL;DR: In this article, an optical-fiber Bragg grating is used as a reflector of the resonant cavity, an active optical fiber capable of generating sufficient gains is added, and a double-wavelength/multiple-wvelength optical fiber grating device is formed under the action of a pump light source.
Abstract: The invention relates to a sensing method with an optical-fiber Bragg grating laser device. An optical-fiber Bragg grating is used as a reflector of the resonant cavity, an active optical fiber capable of generating sufficient gains is added, and a double wavelength/multiple wavelength optical-fiber Bragg grating laser device is formed under the action of a pump light source and used as a sensor.When the outside strain, temperature and other physical quantities act on the sensing system, the beat signal frequency among the double wavelength or multiple wavelength laser can shift, and counterstress, temperature and other physical parameters can be measured precisely by detecting the beat signal frequency information. The invention has the advantages of simple manufacture, stable and reliable operation, stable measurement result and high precision, and is free from the interference of light intensity, polarization and other optical information quantities. The multipoint distribution sensing measurement can be realized in a frequency-division multiplexing mode. An electrooptical modulator is added before the spectrum analyzer starts detection so as to randomly adjust the beat signal frequency, thereby greatly reducing the spectral range of the spectrum analyzer and reducing the detection cost.

Journal ArticleDOI
TL;DR: Following the mid-infrared spectrometer approach, ground state combination differences of molecular ions can be predicted in order to identify them in astronomical objects.
Abstract: A mid-infrared spectrometer consisting of a high power optical parametric oscillator, a frequency comb, and a cold ion trap is described and characterized. The idler frequency at 3 μm is measured accurately by analyzing the pump and signal beat frequencies with the comb. This is done via two spectrum analyzers, allowing for a wide and continuous scanning ideal for spectroscopy of cold molecules with unknown spectra. The potential of this approach is demonstrated by measuring a ro-vibrational line of CH 5+ in a 22-pole ion trap via action spectroscopy of only several thousand cold ions. The current setup limits the precision of the line center frequency determination to some 100 kHz with ample room for future improvements. Following this approach, ground state combination differences of molecular ions can be predicted in order to identify them in astronomical objects.

Journal ArticleDOI
TL;DR: A microwave frequency comb with up to 200th harmonic of a laser repetition rate is generated by nonlinear intermodal mixing of 15 fs laser pulses in the junction of a scanning tunneling microscope as mentioned in this paper.
Abstract: A microwave frequency comb with up to 200th harmonic of a laser repetition rate is generated by nonlinear intermodal mixing of 15 fs laser pulses in the junction of a scanning tunneling microscope. The highest harmonic has an output power of −146 dBm at 14.85 GHz with a signal/noise ratio of 20 dB and a measured linewidth of 1.2 Hz, which is still larger than the actual linewidth due to phase noise of the spectrum analyzer. Theory suggests that the harmonics have comparable magnitude up to terahertz frequencies, while the observed roll-off is caused by a shunting capacitance in detection circuitry.

Patent
26 Sep 2012
TL;DR: In this paper, a fully distributed optical fiber strain and vibration sensor comprising a laser (1), a first coupler (2), a pulse modulation module (3), an optical amplifier (4), a circulator (5), a sensing optical fiber (6), a fiber bragg grating (7), a polarization scrambler, a second coupler, a balance photoelectric detector, an analyzer, a photoelectric detectors (12), and a signal processing unit (13) is presented.
Abstract: The invention discloses a fully distributed optical fiber strain and vibration sensor comprising a laser (1), a first coupler (2), a pulse modulation module (3), an optical amplifier (4), a circulator (5), a sensing optical fiber (6), a fiber bragg grating (7), a polarization scrambler, a second coupler, a balance photoelectric detector, an analyzer, a photoelectric detector (12) and a signal processing unit. Continuous light output by the laser (1) is split into two paths through the first coupler (2), wherein one path is used as reference light and is accessed to a first input end of the second coupler (9) through the polarization scrambler (8); and the second path is processed by the pulse modulation module (3) and the optical amplifier (4) and then used as detection pulse light to be injected into a first port of the circulator (5). In the invention, Brillouin optical time domain reflectometry (BOTDR) and polarization optical time domain reflectometry (POTDR) are simultaneously utilized for respectively and correspondingly carrying out fully distributed measurement on strain and vibration on a signal optical fiber, the defects of a system with single BOTDR or POTDR are overcome, and the false alarm rate or missed report rate of the system is decreased.

Journal ArticleDOI
TL;DR: By using crosscorrelation of the outputs of the two frontends, the effective NF is reduced to around 5 dB, which results in a spurious-free dynamic range of 88 dB in 1 MHz resolution bandwidth.
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.

Journal ArticleDOI
TL;DR: Fast reconstruction of the whole BrillouIn gain spectrum is experimentally demonstrated using sweep-free Brillouin optical time-domain analysis (SF-BOTDA), achieving strain sensitivity of 1 microstrain per root Hz at a sampling rate of 5.5 kHz and spatial resolution of 4m.
Abstract: Fast reconstruction of the whole Brillouin gain spectrum is experimentally demonstrated using sweep-free Brillouin optical time-domain analysis (SF-BOTDA) Strain variations with the frequencies up to 400Hz are spectrally analyzed, achieving strain sensitivity of 1 microstrain per root Hz at a sampling rate of 55kHz and a spatial resolution of 4m The results favorably compare with fiber Bragg grating sensing

Journal ArticleDOI
TL;DR: In this paper, a mathematical model is developed to relate the observed multipath to the internal signal reflection, and the capability to suppress the signal reflection with receiver multipath mitigation methods is demonstrated.
Abstract: A characterization of the signal anomaly of SVN49 is presented. A mathematical model is developed to relate the observed multipath to the internal signal reflection. The analyses provided are based on measurements, which have been collected during a dedicated tracking campaign with a 30-m dish antenna. Data on the L1 and L2 frequency have been collected with four different receivers. In addition, IQ samples have been recorded directly with a spectrum analyzer. The multipath combination of the receiver measurements on L1 and L2 is analyzed to demonstrate the effect of the signal reflections on different correlator spacing. The capability to suppress the signal reflection with receiver multipath mitigation methods is demonstrated. Finally, preliminary estimates of the attenuation, delay, and phase shift over elevation are obtained from an IQ sample analysis.

Patent
26 Jan 2012
TL;DR: In this article, a pickup system includes a wind detector and a wind suppressor, with a ratio calculator configured to generate a ratio of the first and second input signals, and a mixer configured to select one or second input signal and apply to the selected input signal one of first or second panning coefficients based on the wind level indication signal and on the ratio.
Abstract: In one embodiment, a pickup system includes a wind detector and a wind suppressor. The wind detector has a plurality of analyzers each configured to analyze first and second input signals, and a combiner configured to combine outputs of the plurality of analyzers and issue, based on the combined outputs, a wind level indication signal indicative of wind activity. The analyzers can be selected from a group of analyzers including a spectral slope analyzer, a ratio analyzer, a coherence analyzer, a phase variance analyzer and the like. The wind suppressor has a ratio calculator configured to generate a ratio of the first and second input signals, and a mixer configured to select one of the first or second input signals and to apply to the selected input signal one of first or second panning coefficients based on the wind level indication signal and on the ratio.

Proceedings ArticleDOI
01 Dec 2012
TL;DR: This cyclostationary analysis based RF signal analyzer is capable of sensing the existence of primary users and estimating the carrier frequency and symbol rate accurately and the performance in realistic wireless communication channels is validated.
Abstract: Cyclostationary analysis such as spectral correlation function (SCF) and spectral coherence function (SOF) has been accepted as an important tool in signal detection and radio frequency (RF) parameter estimation in cognitive radios. However, cyclostationary analysis requires extremely high resolution to fully observe the cyclic frequency features, leading to very high computational complexity and difficulty in real time implementation, especially on software defined radios where computational capability is limited. In this paper, we implement and demonstrate a real time SCF/SOF RF signal analyzer by adopting previously proposed two-stage dynamic resolution SCF/SOF estimation method using software defined radios. Specifically, high resolution SCF/SOF calculation is only performed near the expected cyclic feature locations obtained through a low complexity coarse estimation employing spectral analysis. This cyclostationary analysis based RF signal analyzer is capable of sensing the existence of primary users and estimating the carrier frequency and symbol rate accurately. Using Universal Software Radio Peripheral (USRP) software defined radio platform and GNU radio software, we implement and demonstrate such a cyclostationary analysis based RF signal analyzer in real time and validate the performance in realistic wireless communication channels.

Journal ArticleDOI
TL;DR: In this paper, a single-shot real-time optical vector spectrum analyzer (VSA) was proposed to enhance the phase reconstruction accuracy and dynamic range for ultrashort optical signals.
Abstract: We introduce and demonstrate a single-shot real-time optical vector spectrum analyzer (VSA). This simple and powerful instrument combines amplified dispersive Fourier transform with stereopsis reconstruction algorithm and is inspired by binocular vision in biological eyes. Moreover, a dynamic time-stretch concept is employed to dramatically enhance the phase reconstruction accuracy and dynamic range for ultrashort optical signals (>; 30 times). We show that, using a noniterative analytical expression, the phase profile of the input signal can be reconstructed using intensity-only measurements. The proposed method is experimentally proved by fully characterizing the time-varying amplitude and phase of single-shot THz-bandwidth optical signals, with durations ranging from sub-ps to 35 000 ps, with ultrasmall to ultralarge temporal phase variations and at 25-MHz update rate. We have also used this instrument to characterize the amplitude and phase of a prechirped 40-Gbps DQPSK optical signal using a 1.5-GHz digitizer and without using a reference signal.

Patent
31 Aug 2012
TL;DR: Disclosed as discussed by the authors is a portable handheld characteristic analyzer used to analyze chemical compositions in or near real-time, and it can be used to determine a characteristic of a sample.
Abstract: Disclosed is a portable handheld characteristic analyzer used to analyze chemical compositions in or near real-time. One method of using the analyzer to determine a characteristic of a sample includes directing the handheld characteristic analyzer at the sample, the handheld characteristic analyzer having at least one integrated computational element arranged therein, activating the handheld characteristic analyzer, thereby optically interacting the at least one integrated computational element with the sample and generating optically interacted light, receiving the optically interacted light with at least one detector arranged within the handheld characteristic analyzer, generating an output signal corresponding to the characteristic of the sample with the at least one detector, receiving the output signal with a signal processor communicably coupled to the at least one detector, and determining the characteristic of the sample with the signal processor.

Patent
24 Oct 2012
TL;DR: In this paper, a self-adaption scanning device with electromagnetic compatibility for a near-field test, which consists of a hardware system and a scanning control software system, was presented.
Abstract: The invention relates to a self-adaption scanning device with electromagnetic compatibility for a near-field test, which consists of a hardware system and a scanning control software system. The hardware system comprises a computer, a spectrum analyzer, a GPIB card for communication between the computer and the spectrum analyzer, a set of near-field probe and pre-amplifier, a control circuit witha single-chip computer as the core, a USB serial cable for connection of the computer and the control circuit, two sets of stepper motor and matching transmission devices and also a three-dimensionalmechanical scanning platform; the scanning control software system comprises a communication program between the computer and the spectrum analyzer, a serial communication program between the computer and the single-chip computer, a driving program for the single-chip computer to control the stepper motor, a program for analysis and display of data and a user-oriented human-computer interaction interface program. The invention has the advantages of scientific concept and novel structure, improves the scanning efficiency and the data accuracy, and has high practical value and broad applicationprospects in the field of testing of the near field with electromagnetic compatibility.

Journal ArticleDOI
TL;DR: In this article, a collinear acousto-optic diffraction of an arbitrarily polarized optical radiation was studied theoretically and experimentally, and it was shown that in the general case the diffracted light spectrum at the acoustoeoptic cell output consists of four components with different frequencies and polarizations, and beatings of these components lead to intensity modulation of the light passed through an output analyzer.
Abstract: Collinear acousto-optic diffraction of an arbitrarily polarized optical radiation is studied theoretically and experimentally. It is shown that in the general case the diffracted light spectrum at the acousto-optic cell output consists of four components with different frequencies and polarizations. Beatings of these components lead to intensity modulation of the light passed through an output analyzer. Dependences of output intensity components on ultrasound frequency and acoustic power are examined for different orientations of the polarizer and the analyzer. Experimental investigations are carried out with a collinear acousto-optic cell fabricated with calcium molybdate single crystal.