Noise Cutoff Frequency Research Articles

Design and analysis of a wideband compact LNA-mixer in millimeter wave frequency

This paper presents the design and analysis of a millimeter-wave LNA-mixer, which adopts a low-noise single-to-differential conversion balun with low phase (gain) imbalance, using a common-source and a common-gate stage. Each stage employs a cascode transistor with inductors in the gate and source for improving noise, gain, and bandwidth performance. A new transformer-based network is proposed for broadband input matching. Also, a transformer network couples between transconductance and switching stage for independent biasing of two stages, which provides passive gain without extra power consumption and further noise reduction. To optimize the size of transistors and their current density, a new figure of merit is utilized which concurrently optimize noise performance, cut-off frequency, and transconductance efficiency. The input frequency range is 27.5–43.5 GHz with typical input signal power of – 40 dBm and a switching signal power of 0dBm, using 0.18 µm CMOS technology. The simulation result shows that typical conversion gain is 24–27 dB, DSB-NF is 5.33–9.1 dB, and third-order intercept point is − 7.83 dBm. The DC power consumption is 11.13 mW with a chip size of 0.45 mm2.

Free, forced, and random vibrations of a beam composed of highly contrasting materials

This study deals with free, forced undamped vibration and the random, damped vibration of an inhomogeneous beam composed of two materials with significantly different elastic moduli and material densities. Exact solution is obtained for natural frequencies and the mode shapes using Krylov-Duncan functions, along with the comparison with the results furnished by the Galerkin's method. Random vibrations of the bi-material beams are studied for the first time in the literature for the case of proportional damping. Novel element of this study consists in the unintuitive finding that the response of the bi-material beam may considerably exceed the responses of its homogeneous counterparts, composed of a single material. This finding appears of design significance, suggesting that the natural frequencies of the bi-material beam must be made so as to lie above the cutoff frequency of broad-band cutted white noise.

Suppressing Random Response of a Regular Structure by an Inerter-Based Dynamic Vibration Absorber

AbstractThis paper concentrates on the random vibration suppression of a regular straight beam by using an inerter-based dynamic vibration absorber. For a wideband random point-driven straight beam with an inerter-based dynamic vibration absorber, the distribution of mean-square velocity response along the axis of the straight beam as well as the mean kinetic energy of the whole beam are first analytically derived through the classical linear random vibration theory. Two optimization objectives are established to determine the optimal design parameters: (1) minimizing the maximal mean-square velocity along the axis of the straight beam, which corresponds to the maximal mean kinetic energy density along the axis and (2) minimizing the mean kinetic energy of the whole beam. Numerical search gives the optimal location and the associated optimal parameters of the inerter-based dynamic vibration absorber. Numerical results for a simply supported straight beam illustrate the better performance of an inerter-based dynamic vibration absorber than a traditional dynamic vibration absorber. Parametric sensitivity studies for the robustness analysis of the beam response to deviations from the optimal parameters are conducted. The optimal location locates on the force-excited point, while the suboptimal location locates on its symmetry position. Furthermore, the optimal and suboptimal locations remain invariable regardless of the upper cutoff frequency of band-limited noise, which is fairly important to the location optimization of the inerter-based dynamic vibration absorber.

Calculation of the impulse response and phase noise of a high-current photodetector using the drift-diffusion equations.

We describe a procedure to calculate the impulse response and phase noise of high-current photodetectors using the drift-diffusion equations while avoiding computationally expensive Monte Carlo simulations. We apply this procedure to a modified uni-traveling-carrier (MUTC) photodetector. In our approach, we first use the full drift-diffusion equations to calculate the steady-state photodetector parameters. We then perturb the generation rate as a function of time to calculate the impulse response. We next calculate the fundamental shot noise limit and cut-off frequency of the device. We find the contributions of the electron, hole, and displacement currents. We calculate the phase noise of an MUTC photodetector. We find good agreement with experimental and Monte Carlo simulation results. We show that phase noise is minimized by having an impulse response with a tail that is as small as possible. Since, our approach is much faster computationally than Monte Carlo simulations, we are able to carry out a broad parameter study to optimize the device performance. We propose a new optimized structure with less phase noise and reduced nonlinearity.

Simple programmable voltage reference for low frequency noise measurements

The paper presents a circuit design of a low-noise voltage reference based on an electric double-layer capacitor, a microcontroller and a general purpose DAC. A large capacitance value (1F and more) makes it possible to create low-pass filter with a large time constant, effectively reducing low-frequency noise beyond its bandwidth. Choosing the optimum value of the resistor in the RC filter, one can achieve the best ratio between the transient time, the deviation of the output voltage from the set point and the minimum noise cut-off frequency. As experiments have shown, the spectral density of the voltage at a frequency of 1 kHz does not exceed 1.2 nV/√Hz; the maximum deviation of the output voltage from the predetermined does not exceed 1.4 % and depends on the holding time of the previous value. Subsequently, this error is reduced to a constant value and can be compensated.

More about monaural noise edge pitch

Lowpass noise with a sharp spectral cutoff generates a monaural noise edge pitch (MNEP) that listeners match with a sine tone having a frequency somewhat below the noise cutoff frequency (negative pitch shift). If the MNEP is a proper musical pitch, listeners should be able to identify musical intervals made using only the MNEP stimulus. Open-set MNEP experiments in the edge-frequency range of 600-2400 Hz found that four out of four listeners with musical training correctly identified octaves, fifths, fourths, and major thirds, proving that the MNEP is a musical pitch. The MNEP can be heard for edge frequencies at least as low as 100 Hz, but the negative pitch shift becomes larger than a semitone, consistent with a timing model of the MNEP having a fixed integration time. If the MNEP reflects the expected quasi-periodic timing response of the auditory system to a sharp spectral edge, the pitch should become inaudible if the edge frequency becomes too high for neural synchrony—expected to be about 5000 Hz. Sine tone pitch matching experiments showed that such a limit clearly applies for most listeners, but less clearly for others. [Work supported by the USAFOSR.]

IQ quadrature demodulation algorithm used in heterodyne detection

In order to obtain better detection results of heterodyne, we used phase IQ quadrature demodulation algorithm to process the data which detected by laser heterodyne. Based on laser heterodyne interferometer, processing the data in the interferometer phase IQ quadrature demodulation algorithm from the signal to noise ratio, sampling rate, sampling rate, filter order and cutoff frequency, verify the effects of these system parameters to the phase precision, and choose the best parameters to obtain a better phase precision through experiment as: the signal to noise ratio is 25dB, the IF signal frequency is 98.3MHz, 98.5MHz, 99.1MHz, 99.5MHz and 100MHz, the sampling rate is 512–2048, the cutoff frequency and order of the filter are 0.11 and 40, respectively.

Realization of nonequilibrium thermodynamic processes using external colored noise.

We investigate the dynamics of single microparticles immersed in water that are driven out of equilibrium in the presence of an additional external colored noise. As a case study, we trap a single polystyrene particle in water with optical tweezers and apply an external electric field with flat spectrum but a finite bandwidth of the order of kHz. The intensity of the external noise controls the amplitude of the fluctuations of the position of the particle and therefore of its effective temperature. Here we show, in two different nonequilibrium experiments, that the fluctuations of the work done on the particle obey the Crooks fluctuation theorem at the equilibrium effective temperature, given that the sampling frequency and the noise cutoff frequency are properly chosen.

Effect of Several Parameters on Pitch Perception of Unresolved Harmonics

This paper studied the effect of several parameters on pitch perception of unresolved harmonics by measuring fundamental frequency difference limens. The parameters included roving fundamental frequency or not, type of background noise, and cutoff frequency of lowpass pink noise. Results found that performance was significantly worse when the fundamental frequency was roved than the constant case, lowpass pink noise had similar ability to mask combination tones as threshold equalizing noise, and that combination tones could be masked if the cutoff frequency of the lowpass pink noise was not lower than the frequency of the tenth harmonic. This paper proposed a set of appropriate parameters for experiments of pitch perception, which suggested that roving fundamental frequency, using threshold equalizing noise with the level of about 8-13 dB below the level per component of the stimuli, or using lowpass pink noise with the cutoff frequency not lower than the frequency of the tenth harmonic, can achieve effective performance for pitch perception.

Multistate intermittency and extreme pulses in a fiber laser

In our recent Letter [Phys. Rev. Lett. 107, 274101 (2011)], we demonstrated that slow random perturbations of a system parameter were responsible for the emergence of rogue waves in a fiber laser with coexisting attractors. In this paper we investigate how the probability of a particular state to appear in multistate intermittency can be controlled by low-pass noise filtering. We show that the probability of some states depends nonmonotonously on the noise amplitude and cutoff frequency. The conditions for the emergence of extreme pulses in a erbium-doped fiber laser are analyzed numerically and experimentally.

Características acústicas dos fones [s] e [∫] de adultos e crianças com desenvolvimento fonológico típico

OBJETIVO: Comparar as produções de [s] e [∫] de adultos e crianças com desenvolvimento fonológico típico, considerando os parâmetros acústicos: duração do ruído fricativo, banda de frequências de concentração do ruído, frequência de corte de ruído de fricção e transição formântica da vogal seguinte. MÉTODOS: Participaram do estudo 26 sujeitos, divididos em dois grupos: Grupo de adultos (GA) - composto por 17 adultos jovens (média de idade: 23,61±3,44 anos), sem alterações em aspectos fonológicos da língua e; Grupo de crianças com desenvolvimento fonológico típico (GDFT) - composto por nove crianças (média de idade: 7,12±0,74 anos), com desenvolvimento fonológico típico. Foi realizada uma triagem fonoaudiológica e, após, coleta de dados para análise acústica e, para isso, foram utilizadas pseudopalavras inseridas em frases-veículo. Foram analisadas 624 produções dos sujeitos e os achados foram submetidos à análise estatística. RESULTADOS: Os parâmetros de banda de frequências e transição formântica apresentaram diferenças entre os grupos GA e GDFT. Na comparação entre as posições na palavra, os parâmetros de duração, frequência de corte e transição formântica apresentaram diferença. Os parâmetros de frequência de corte, banda de frequências e transição formântica apresentaram diferença na comparação entre os pontos de articulação de [s] e [∫]. CONCLUSÃO: Para a maioria dos parâmetros acústicos estudados, as produções de GA e GDFT mostraram-se semelhantes. Para alguns parâmetros, porém, puderam-se observar diferenças entre os grupos, entre as posições na palavra e entre os pontos de articulação dos fones estudados.

Sub-Micron Area Heterojunction Backward Diode Millimeter-Wave Detectors With 0.18 ${\rm pW/Hz}^{1/2}$ Noise Equivalent Power

InAs/AlSb/AlGaSb heterojunction backward diodes are promising detectors for millimeter-wave imaging applications due to their high sensitivity, low noise, and high cutoff frequency. By using a device heterostructure with a thin (11 Å) barrier layer, δ-doped cathode, and optimized AlxGa1-xSb anode composition (x=12%), in conjunction with submicron (0.4×0.4 μm2) active area, fabricated detectors have demonstrated DC curvatures of -47 V-1 and record unmatched sensitivities of 4600 V/W at 94 GHz. Impedance-matched sensitivities of 49,700 V/W at 94 GHz are projected from on-wafer S-parameter and sensitivity measurements. These detectors have measured junction resistances of 814 Ω·μm2 and capacitances of 15 fF/μm2. A record low NEPmin of 0.18 pW/Hz1/2 has been projected under conjugate matching conditions. This study demonstrates the potential of Sb-heterostructure backward diodes as ultra-low-noise millimeter-wave direct detectors.

무선 간섭 제거 중계기에서 적응형 위상 잡음 보상기 연구

In this paper, we study a novel wireless interference cancellation system(ICS) repeater based on OFDM system with phase noise analysis and performance evaluation. Recently, there were many researches about wireless repeater. The previous study is just considering the feedback channel cancellation algorithm. But, in wireless repeater system, the phase noise effect can exist at up and down converter of wireless repeater. In wireless repeater system, if there are phase noise effects, the performance of system will get worse. So, the phase noise compensator is needed in wireless repeater. Therefore, we propose adaptive phase noise compensator based on OFDM system in order to effectively cancel phase noise. In order to cancel interference, we adapt adaptive phase noise compensator in wireless repeater system. The adaptive phase noise compensator compensates phase noise effect. Therefore, in this paper, we analyze phase noise of wireless repeater based on OFDM system. In this paper, when phase noise power is -15 dBc and phase noise cutoff frequency is 100 kHz at 4QAM, the BER performance of propose algorithm is better about 4 dB than with adaptive equalizer and without phase noise compensator at .

Noise Effects on Threshold of Electrohydrodynamic Convection in Nematic Liquid Crystals

New experimental aspects of multiplicative noise effects on the onset of ac-driven electroconvection in nematic liquid crystals are presented. In the superposition of a stochastic field with a deterministic one, the variation in the threshold voltage V c (of the deterministic one) was investigated as a function of the intensity ( V N ), cutoff frequency ( f c ), and correlation time (τ N ) of the stochastic noise. In particular, it is observed that the noise effects vanish for certain stochastic and deterministic conditions.

Information gain in an optical bistable system by stochastic resonance

We have shown an experimental demonstration of information gain due to the stochastic resonance in an optical bistable system, that is, information hidden in the input wave form appears in the output of a nonlinear system when the input noise amplitude is adequate. The optical bistable system is a hybrid type comprising a LiNbO3 crystal with an electric feedback loop, and the input of the system is the sum of a binary bit series and a Gaussian colored noise. The information gain is proved to be prominent when the noise cutoff frequency is larger than the bit rate.

Spectral contributions to the benefit from spatial separation of speech and noise.

Speech recognition in noise improves when speech and noise sources are separated in space. This benefit has two components whose effects are strongest in different frequency regions: (1) interaural level differences (e.g., head shadow), which are largest at higher frequencies, and (2) interaural time differences, which have their greatest contribution at lower frequencies. Binaural interactions enhance the separation of signals from noise through the use of these interaural differences. Here, the benefit attributable to spatial separation was measured as a function of the low- and high-pass cutoff frequency of speech and noise. Listeners were younger adults with normal hearing, older adults with normal hearing, and older adults with hearing loss. Binaural thresholds for narrowband noises were measured in quiet and in a speech-shaped masker as a function of masker low-pass cutoff frequency. Speech levels corresponding to 50% correct recognition of sentences from the Hearing in Noise Test (HINT) were measured in a 65-dB SPL speech-shaped noise. Thresholds for narrowband noises and for speech were measured with two loudspeaker configurations: (1) signals and speech-shaped noise at 0 degrees azimuth (in front of the listener) and (2) signals at 0 degrees azimuth and speech-shaped noise at 90 degrees azimuth (at the listener's side). The criterion measure was spatial separation benefit, or the difference in thresholds for the two conditions. Benefit of spatial separation for unfiltered speech averaged 6.1 dB for younger listeners with normal hearing, 4.9 dB for older listeners with normal hearing, and 2.7 dB for older listeners with hearing loss. Benefit was differentially affected by low-pass and high-pass filtering, suggesting a trade-off of the contributions of higher frequency interaural level differences and lower frequency interaural timing cues. As expected, older listeners with hearing loss benefited little from the improved signal-to-noise ratios in the higher frequencies resulting from head shadow, but showed some benefit from lower frequency cues. Spatial benefit for older listeners with normal hearing was reduced relative to benefit for younger listeners. This result may be related to older listeners' elevated thresholds at frequencies above 6.0 kHz.

Noise-enhanced transmission of information in a bistable system

Stochastic resonance (SR) in a bistable system with a binary input signal is studied by numerical simulation. The mutual information (MI) is used as a measure of information. We show that MI shows the resonance peculiar to SR and that the output MI of the bistable system can exceed the input one, that is, MI can have gain. The dependence of the resonance signal and the gain of MI on the noise cutoff frequency is studied and it is shown that the noise with large cutoff frequency is favorable for SR and for the gain of MI. To show the characteristics and the benefits of this type of SR and the gain of MI, the behavior of SR in the bistable system for image data is simulated. The simulation results show that this system can improve the visibility of images.

Noise-Color Dependence of Stochastic Resonance Signals in a Hybrid Optical Bistable System

An experiment of stochastic resonance (SR) using well-characterized colored noise was performed in an optical bistable system. The resonance signal peculiar to SR was observed, and the dependence of the resonance signal on the noise cutoff frequency was studied. The SR experiment was well reproduced by a numerical simulation using a model system.

Effect of stimulus rise time and high-pass masking on early auditory evoked potentials

Problems of frequency-specific objective assessment of hearing threshold by means of auditory brainstem response (ABR) have been discussed recently. While a number of workers have recommended methods of selective masking to improve the frequency specificity, others believe that frequency-specific potentials can also be obtained without masking. In this context, the effects of rise-decay time and high-pass masking on ABRs were investigated. ABRs were recorded in normal-hearing subjects and patients with high and low frequency hearing loss by means of surface electrodes between the vertex and the ipsilateral mastoid. The frequency of the stimulus was 1 kHz, and the rise-decay time 1 ms (1-0-1) or 2 ms (2-0-2). High-pass filtered noise (cutoff frequency 1.5 kHz; filter slope 250 dB/octave) was employed for masking. Particular attention was paid to the problem of efficient masking. In normal-hearing subjects under the influence of high-pass masking compared to non-masked ABRs, longer mean latencies and diminished means of the amplitudes of wave V were found, with differences in the near-threshold domain being less pronounced. Similar results were observed in patients with high frequency hearing loss. In patients with low frequency hearing loss, the influence of high-pass masking was especially marked distinctly near to threshold. Furthermore, latency and amplitude differences of wave V of the 1-0-1 and the 2-0-2 stimuli were determined from the ABRs obtained with and without high-pass masking. The differences between the latency differences of both stimuli in the suprathreshold range (70 dB nHL) only were statistically significant. The results are suggestive of an inadequate frequency specificity of unmasked stimuli in the suprathreshold range. Evaluation of the latencies revealed for both rise-decay times a similar frequency specificity near the threshold and a higher frequency specificity of the longer stimulus in the suprathreshold range.

Kilohertz Quasi-periodic Oscillation and Atoll Source States in 4U 0614+09

We report three RXTE/PCA observations of the low-mass X-ray binary 4U 0614+09. They show strong ( ~30% rms) band-limited noise with a cutoff frequency varying between 0.7 and 15 Hz in correlation with the X-ray flux, fX. We observe two nonsimultaneous 11%-15% (rms) kHz peaks near 728 and 629 Hz in the power spectra of two of our observations when fX ~ 10-9 ergs cm-2 s-1 (2-10 keV) but find no quasi-periodic oscillations (QPOs; <6% rms) when fX is half that. We suggest that count rate may not be a good measure for dot M even in sources as intrinsically weak as 4U 0614+09 and that QPO frequency and noise cutoff frequency track dot M more closely than count rate. The QPO increases in rms amplitude from 11% ± 1.3% at 3 keV to 37% ± 12% at 23 keV; the fractional amplitude of the band-limited noise is energy independent. This suggests different sites of origin for these two phenomena. The spectrum of the oscillating flux roughly corresponds to a black body with temperature 1.56 ± 0.2 keV and radius 500 ± 200 m (other models fit as well), which might indicate that the oscillations originate at a small region on the neutron star surface.