scholarly journals Frequency Selectivity in the Ampullary System of an Elasmobranch Fish (Scyliorhinus Canicula)

1985 ◽  
Vol 118 (1) ◽  
pp. 99-109 ◽  
Author(s):  
R. C. PETERS ◽  
H. P. EVERS
Keyword(s):  
Low Frequency ◽  
Frequency Discrimination ◽  
Primary Afferents ◽  
Optical Recording ◽  
Phase Changes ◽  
Electrophysiological Recording ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Tuning Curves ◽  
Scyliorhinus Canicula

1. Frequency characteristics of the electroreceptive system in Scyliorhinus canicula were determined both by electrophysiological recording of the primary afferent responses and by optical recording of respiratory reflexes after electrical stimulation. 2. The frequency response of the primary afferents shows a maximum gain at about 5 Hz, with slopes of +2.3 and −3.4 dB octave−1 at the low and high frequency side respectively. The phase changes from +60° at 0.03 Hz to −120° at 15 Hz. 3. The sensitivity curve determined by recording the respiratory reflex has a plateau from 0.1 to 1 Hz, with slopes of +2.8 and -;11.4dB octave−1. The highest sensitivity for sinusoidal electrical stimuli was 40nV cm−1 peak-to-peak, in the frequency range 0.1 to 1 Hz. 4. We suggest that the difference between the two curves reflects the convergence of primary afferents on to secondary neurones. 5. We conclude that the low pass filter properties are not imposed by the time constant of the ampulla wall. 6. The low frequency slope found in the behavioural curve presumably represents the slope of the receptor-cell-synapse complex. 7. The Lorenzinian ampullae apparently act as peripheral filters with different tuning curves; these must play a part in frequency discrimination.

scholarly journals Ladder-Based Synthesis and Design of Low-Frequency Buffer-Based CMOS Filters

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2931
Author(s):  
Waldemar Jendernalik ◽  
Jacek Jakusz ◽  
Grzegorz Blakiewicz
Keyword(s):  
Dynamic Range ◽  
Low Voltage ◽  
Supply Voltage ◽  
Low Frequency ◽  
Cmos Technology ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Biomedical Sensors ◽  
Filter Synthesis ◽  
Cascade Method

Buffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more general method for buffer-based filter synthesis is developed and presented. The method uses RLC ladder prototypes to obtain filters of arbitrary orders. In addition, a set of novel circuit solutions with ultra-low voltage and power are proposed. The introduced circuits were synthesized and simulated using 180-nm CMOS technology of X-FAB. One of the designed circuits is a fourth-order, low-pass filter that features: 100-Hz passband, 0.4-V supply voltage, power consumption of less than 5 nW, and dynamic range above 60 dB. Moreover, the total capacitance of the proposed filter (31 pF) is 25% lower compared to the structure synthesized using a conventional cascade method (40 pF).

scholarly journals Prediction of Favorable Carbonate Reservoirs under Extremely Thick Salts via Poststack Facies-Controlled and Prestack Zoeppritz Equation Inversions in the Santos Basin of Brazil

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Sheng Zhang ◽  
Suoliang Chang ◽  
Handong Huang ◽  
Yinping Dong ◽  
Youyi Shen ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Large Angle ◽  
Low Frequency ◽  
Prediction Method ◽  
Approximate Equation ◽  
Carbonate Reservoirs ◽  
Linear Inversion ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Oil And Gas Exploration

Subsalt carbonate rocks in Brazil’s deepwater region have broad prospects for oil and gas exploration and development. Due to the low-frequency bandwidth of the seismic data and the poor signal quality for this kind of reservoir target, there is a demand for accurate seismic prediction methods. We employ the facies-controlled inversion using a low-pass filter matrix to ensure the accuracy of the low frequency and to improve the robustness of the inversion results. We integrated the concept of adaptive regularization constraint of the Zoeppritz equation into the generalized linear inversion theory framework, which overcomes the shortcomings of the approximate equation. Making full use of the large angle prestack seismic information, Zoeppritz equation inversion improves the accuracy of the inversion results. The application of this method in carbonate reservoirs under extremely thick salts in the Santos Basin of Brazil indicates the feasibility and practicality of the proposed integrated prediction method.

A New Capacitance Multiplier Structure with High Multiplication Factor for Ultra-Low-Frequency Filter in Biomedical Applications

2019 ◽  
Vol 29 (07) ◽  
pp. 2050109
Author(s):  
Yan Li ◽  
Yong Liang Li
Keyword(s):  
Biomedical Applications ◽  
Low Frequency ◽  
Multiplication Factor ◽  
Frequency Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Physiological Signal ◽  
Wide Range ◽  
Low Pass ◽  
Capacitance Multiplier

A novel capacitance multiplier is proposed to implement an ultra-low-frequency filter for physiological signal processing in biomedical applications. With the proposed multiplier, a simple first-order low-pass filter achieves a [Formula: see text]3-dB frequency of 33.4[Formula: see text]μHz with a 1-pF capacitance and a 20[Formula: see text]k[Formula: see text] resistance. This corresponds to a multiplication factor of as large as [Formula: see text]. By changing the controlling terminal, the [Formula: see text]3-dB frequency can be tuned in a wide range of 33.4[Formula: see text]μHz–6.3[Formula: see text]kHz.

Design of the Broadband Standard Signal Generator for Laser Locating System of the Mine Hoisting Container

2013 ◽  
Vol 427-429 ◽  
pp. 2033-2036
Author(s):  
Di Fan ◽  
Yan Gao ◽  
Yue Zhao
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Frequency Standard ◽  
Analog Filters ◽  
Laser Ranging ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Disturbance ◽  
Standard Signal ◽  
Low Pass

As the key junction between the ground and underground, hoisting systems as well as mines themselves are of vital importance to coalmine production. Laser ranging method is studied as a new solution of getting the real-time position directly. Furthermore, multi-scale phase based laser ranging principles are utilized in the system. The paper is aimed to conduct research into the problems existing in standard signal generating while using laser to locating the hoisting container, and to design standard sine generator circuits with DDS technology and DDS devices AD9850 to generate multiple frequency standard signals. In view of the serious noise disturbance in high frequency output, 4-order Chebyshev low-pass filter is designed, by using the integrated analog filters LT 6600-15, to filter the sine signals from AD9850 and to effectively weaken the noise disturbance. The established practical circuits are tested, obtaining trillion level high frequency and low frequency sine signals and fulfilling the requirements for the location system of hoisting containers.

scholarly journals EXPERIMENTAL EVIDENCE FOR VIBRATIONAL RESONANCE AND ENHANCED SIGNAL TRANSMISSION IN CHUA'S CIRCUIT

2013 ◽  
Vol 23 (11) ◽  
pp. 1350189 ◽  
Author(s):  
R. JOTHIMURUGAN ◽  
K. THAMILMARAN ◽  
S. RAJASEKAR ◽  
M. A. F. SANJUÁN
Keyword(s):  
Experimental Evidence ◽  
Low Frequency ◽  
Signal Propagation ◽  
Chua’S Circuit ◽  
Vibrational Resonance ◽  
Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Chua's Circuit ◽  
Wide Range

We consider a single Chua's circuit and a system of a unidirectionally coupled n-Chua's circuits driven by a biharmonic signal with two widely different frequencies ω and Ω, where Ω ≫ ω. We show experimental evidence for vibrational resonance in the single Chua's circuit and undamped signal propagation of a low-frequency signal in the system of n-coupled Chua's circuits where only the first circuit is driven by the biharmonic signal. In the single circuit, we illustrate the mechanism of vibrational resonance and the influence of the biharmonic signal parameters on the resonance. In the n(=75)-coupled Chua's circuits enhanced propagation of low-frequency signal is found to occur for a wide range of values of the amplitude of the high-frequency input signal and coupling parameter. The response amplitude of the ith circuit increases with i and attains a saturation. Moreover, the unidirectional coupling is found to act as a low-pass filter.

scholarly journals Inductanceless high order low frequency filters for medical applications

2022 ◽  
Vol 12 (2) ◽  
pp. 1299
Author(s):  
Noor Thamer Almalah ◽  
Faris Hasan Aldabbagh
Keyword(s):  
Integrated Circuit ◽  
Low Frequency ◽  
Negative Resistance ◽  
Acceptable Result ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Transconductance Amplifier ◽  
Low Pass ◽  
Minimum Number ◽  
Order Butterworth Filter

<p>In this paper, a designed circuit used for low-frequency filters is implemented and realized the filter is based on frequency-dependent negative resistance (FDNR) as an inductor simulator to substitute the traditional inductance, which is heavy and high cost due to the coil material manufacturing and size area. The simulator is based on an active operation amplifier or operation transconductance amplifier (OTA) that is easy to build in an integrated circuit with a minimum number of components. The third and higher-order Butterworth filter is simulated at low frequency for low pass filter to use in medical instruments and low-frequency applications. The designed circuit is compared with the traditional proportional integral controller enhanced (PIE) and T section ordinary filter. The results with magnitude and phase response were compared and an acceptable result is obtained. The filter can be used for general applications such as medical and other low-frequency filters needed.</p>

TECHNIQUE OF APPLICATION FOR PROCESSING OF LOW PASS FILTER LF SIGNALS

10.12737/7905 ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 35-38
Author(s):  
Табаков ◽  
Yu. Tabakov ◽  
Лавлинский ◽  
V. Lavlinskiy
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
Low Frequency ◽  
Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Mathematical Model ◽  
40 Hz

The article includes a block diagram and the mathematical model for low pass filter designed for processing low frequency signal with a frequency of 10-40 Hz in order of eliminate various noises and interference.

The influence of the planted geophone on seismic land data

Geophysics ◽  
1980 ◽  
Vol 45 (8) ◽  
pp. 1239-1253 ◽  
Author(s):  
G. M. Hoover ◽  
J. T. O’Brien
Keyword(s):  
Seismic Data ◽  
High Frequency ◽  
Mineral Exploration ◽  
Low Frequency ◽  
Soil Consolidation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Strong Damping ◽  
Local Soil ◽  
Oscillatory Coupling

Characteristics of the seismic data acquisition system that previously have been ignored become important as more sophisticated interpretive methods based on broader frequency bandwidths are developed to extract stratigraphic information from land data in hydrocarbon and mineral exploration. Theoretical and experimental results indicate that the geophone plant can be approximated by a damped oscillatory coupling, properties dependent upon the geophone mass, dimension of earth contact, and local soil consolidation. A massive geophone with minimal earth contact exhibits a low‐frequency plant resonance with weak damping and acts as a low‐pass filter to eliminate the high‐frequency components of a recorded signal. A lightweight geophone with large earth contact exhibits a high‐frequency plant resonance with strong damping and, consequently, filtering effects are minimal if the plant resonance is well above the signal bandwidth. Although signal filtering influences are weak for strong damping, phase delays can introduce errors of several milliseconds which resemble static errors. Additional complications arise since these time shifts are frequency dependent and, consequently, not identical for all reflection events in a seismic trace. The resonant frequency of the geophone plant increases with increased soil consolidation; however, damping demonstrates only a weak dependence upon consolidation. All of these factors can limit the effectiveness of common‐depth‐point (CDP) stacking methods if the proper technique is not practiced in the acquisition of broad‐bandwidth seismic data.

Acoustic Perturbation Effects on the Fluid Dynamics and Swirling Flame Response in a Non-Premixed Co-Flow Burner

2010 ◽  
Author(s):  
Uyi Idahosa ◽  
Abhishek Saha ◽  
Navid Khatami ◽  
Chengying Xu ◽  
Saptarshi Basu
Keyword(s):  
Heat Release ◽  
Low Frequency ◽  
Ccd Camera ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Fuel Flow ◽  
Flame Dynamics ◽  
Flame Response ◽  
Low Pass ◽  
Swirling Flame

An investigation into the response of non-premixed swirling flames to acoustic perturbations at various frequencies (fp = 0–315 Hz) and swirl intensities (S = 0.09 and 0.34) is carried out. Perturbations are generated using a loudspeaker at the base of an atmospheric co-flow burner with resulting velocity oscillation amplitudes |u′/Uavg| in the 0.03–0.30 range. The dependence of flame dynamics on the relative richness of the flame is investigated by studying various constant fuel flow rate flame configurations. Flame heat release is quantitatively measured and simultaneously imaged using a photomultiplier (PMT) and a phase-locked CCD camera. Both of which are fitted with 430nm bandpass filters for observing CH*chemiluminescence. The flame response is observed to exhibit a low-pass filter characteristic with minimal flame response beyond pulsing frequencies of 200Hz. Flames at lower fuel flow rates are observed to remain attached to the central fuel pipe at all acoustic pulsing frequencies. PIV imaging of the associated isothermal fields show the amplification in flame aspect ratio is caused by the narrowing of the inner recirculation zone (IRZ). The Rayleigh criterion (R) is used to assess the potential for instability of specific perturbation configurations and is found to be a good predictor of unstable modes. Phase conditioned analysis of the flame dynamics yield additional criteria in highly responsive modes to include the effective amplitude of velocity oscillations induced by the acoustic pulsing. Highly amplified responses were observed in pulsed flame configurations with Strouhal numbers (St = fpUavg/dm) in the 1–3.5 range. Heat release to velocity perturbation time delays on the order of the acoustic pulsing period also characterized the highly responsive flames. Finally, wavelet analyses of heat release perturbations indicate sustained low frequency oscillations that become more prominent for low acoustic pulsing frequencies in lean flame configurations.

Sign in / Sign up

Export Citation Format

Share Document