Now showing items 8-27 of 30

    • Double Coil-Less Fluxgate in Bridge Configuration 

      Author: Butta, M.; Ripka, P.; Navarrete, Joaquín Pérez; Vázquez, M.
      (IEEE, 2010-02)
      In this paper, a new method for excitation of coil-less fluxgate is presented. The purpose of this method is to reduce the spurious component of the output voltage, allowing us to increase the amplification. The method is ...
    • Double-Core GMI Current Sensor 

      Author: Malátek, Michal; Ripka, Pavel; Kraus, Luděk
      (IEEE, 2005-10)
      A novel design of the giant magnetoimpedance contactless current sensor is presented. A double-core structure is used in order to improve the temperature stability. The temperature coefficient of sensitivity and offset ...
    • The effect of conductor permeability on electric current transducers 

      Author: Mirzaei, Mehran; Ripka, Pavel; Chirtsov, Andrey; Kašpar, Petr; Vyhnánek, Jan
      (American Institute of Physics, 2018)
      In this paper, experimental works and theoretical analysis are presented to analyze the influence of the conductor permeability on the precision of yokeless current sensors. The results of finite-element method (FEM) fit ...
    • Effect of speech activity parameter on PESQ's predictions in presence of independent and dependent loses 

      Author: Počta, P.; Holub, J.
      This paper deals with the investigation of PESQ's (Perceptual Evaluation of Speech Quality; also known as ITU-T Recommendation P.862) behavior under independent and dependent loss conditions from a speech activity parameter ...
    • Evaluation of Objective Speech Transmission Quality Measurements in Packet-based Networks 

      Author: Slavata, O.; Holub, J.
      This paper presents an analysis of the relation between IP channel characteristics and final voice transmission quality. The NISTNet emulator is used for adjusting the IP channel network. The transmission quality criterion is ...
    • Excitation and Temperature Stability of PCB Fluxgate Sensor 

      Author: Tipek, Alois; O’Donnell, Terence; Ripka, Pavel; Kubík, Jan
      (IEEE, 2005-12)
      Printed circuit board (PCB) integrated inductors have been adapted for operation as fluxgate sensors. A ring core is made from an electrodeposited permalloy thin film and is sandwiched between the layers of the PCB. The ...
    • Fluxgate sensor with increased homogeneity 

      Author: Ripka, Pavel; Jireš, František; Macháček, Milan
      (IEEE, 1990-09)
      Several types of fluxgate sensors were developed for measuring microvariations of the earth's magnetic field. Sensor cores were produced by etching, leading to better geometric homogeneity and long-term stability. This ...
    • Fluxgate: Tuned vs. Untuned Output 

      Author: Ripka, Pavel; Billingsley, S.W.
      (IEEE, 1998-07)
      Fluxgate voltage output contains information about the measured DC magnetic field in amplitude of even harmonic components. Tuning the sensor output causes the concentration of output energy to specific harmonics (usually ...
    • Giant Magnetoimpedance Sensors 

      Author: Hauser, Hans; Kraus, Luděk; Ripka, Pavel
      (IEEE, 2001-06)
      Magnetoinductance and giant magnetoimpedance (GMI) sensors have greatly benefited from the development of amorphous wires. These soft ferromagnetic substances exhibit exquisite sensitivity (in the nT range) and wide bandwidth ...
    • Impact of Different Active-Speech-Ratios on PESQ’s Predictions in Case of Independent and Dependent Losses (in Presence of Receiver-Side Comfort-Noise) 

      Author: Počta, P.; Holub, J.; Vlčková, H.; Polková, Z.
      This paper deals with the investigation of PESQ’s behavior under independent and dependent loss conditions from an Active-Speech-Ratio perspective in presence of receiver-side comfort-noise. This reference signal ...
    • Impact of Different Active-Speech-Ratios on PESQ’s Predictions in Simulated VoIP Environment 

      Author: Počta, P.; Holub, J.; Mrvová, M.
      In this work, we experimentally study how behaviour of the PESQ predictions varies with reference signal characteristic. In particular we investigate the impact of different Active-Speech-Ratios on speech quality ...
    • Inductance position sensor for pneumatic cylinder 

      Author: Ripka, Pavel; Chirtsov, Andrey; Mirzaei, Mehran; Vyhnánek, Jan
      (American Institute of Physics, 2018)
      The position of the piston in pneumatic cylinder with aluminum wall can be measured by external inductance sensor without modifications of the aluminum piston and massive iron piston rod. For frequencies below 20 Hz the ...
    • Influence of External Current on Yokeless Electric Current Transducers 

      Author: Ripka, P.; Chirtsov, A.
      (IEEE, 2017)
      Yokeless electric current transducers have compact size, but they are sensitive to external magnetic fields, including those caused by electric currents in their vicinity. It is often believed that this unwanted sensitivity ...
    • Linearity of Pulse Excited Coil-Less Fluxgate 

      Author: Butta, Mattia; Ripka, Pavel
      (IEEE, 2009-10)
      In this paper, we study the open-loop linearity of pulse excited coil-less fluxgate. Narrow current pulses can be used instead of classical sinewave for the excitation of the coil-less fluxgate. This method has shown several ...
    • Low-Power Printed Circuit Board Fluxgate Sensor 

      Author: Kubík, Jan; Pavel, Lukáš; Ripka, Pavel; Kašpar, Petr
      (IEEE, 2007-02)
      A new printed circuit board flat fluxgate sensor with integrated coils and amorphous alloy core was developed and its excitation parameters optimized for low-power consumption. The power consumption achieved with 10 kHz, ...
    • Magnetic Microwires With Field-Induced Helical Anisotropy for Coil-Less Fluxgate 

      Author: Butta, M.; Ripka, P.; Infante, G.; Badini-Confalonieri, G. A.; Vázquez, M.
      (IEEE, 2010-07)
      We present a new method for production of magnetic microwire with helical anisotropy. Coil-less fluxgate sensors are generally composed of a bimetallic wire excited by an alternating current; in order for the wire to work ...
    • Multiple Layer Scanning in Magnetopneumography 

      Author: Tomek, Jiří; Platil, Antonín; Ripka, Pavel
      (IEEE, 2009-04)
      In magnetopneumography (MPG), we scan weak remanent magnetic fields (in the range of nT) of ferromagnetic dust deposited in the lungs of affected workers. This is carried out in an unshielded lab. Variations of the background ...
    • Off-Center Error Correction of AMR Yokeless Current Transducer 

      Author: Mlejnek, Pavel; Ripka, Pavel
      (Hindawi Publishing Corporation, 2017)
      We present a method of calibration and error correction of the AMR yokeless current transducer consisting of a circular array of eight anisotropic magnetoresistors (AMR) with one feedback compensation loop. The main sources ...
    • Predicting the Quality of Synthesized and Natural Speech Impaired by Packet Loss and Coding Using PESQ and P.563 Models 

      Author: Počta, P.; Holub, J.
      This paper investigates the impact of independent and dependent losses and coding on speech quality predictions provided by PESQ (also known as ITU-T P.862) and P.563 models, when both naturally-produced and synthesized speech ...
    • Pulse Excitation of Micro-Fluxgate Sensors 

      Author: Ripka, Pavel; Choi, San On; Tipek, Alois; Kawahito, Shoji; Ishida, Makoto
      (IEEE, 2001-07)
      Miniature fluxgate sensors with symmetrical closed core elements on both sides of the planar coils were manufactured using standard microtechnology. The new sensors have shown substantial improvement over the standard ...