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Resistorless Current-Mode First-Order All-Pass Filter with Electronic Tuning Employing Low-Voltage CBTA and Grounded Capacitor
(World Scientific Publishing Company, 2018-02-01) Herencsár, Norbert; Koton, Jaroslav; Lahiri, Abhirup; Ayten, Umut E.; Sagbas, Mehmet
In this paper, a new realization of a current-mode first-order all-pass filter (APF) using a single active building block (ABB) and one grounded capacitor is presented. As the ABB, the current backward transconductance amplifier (CBTA) is used, which is one of the most recently reported active elements in the literature. The theoretical results are in detail verified by numerous SPICE simulations using a new low-voltage implementation of CBTA. In the design, the PTM 90 nm level-7 CMOS process BSIM3v3 parameters with ±0.45 V supply voltages were used. The proposed resistorless CBTA-C APF provides easy electronic tuning of the pole frequency in frequency range from 763 kHz to 17.6 MHz, which is more than one decade. Maximum power dissipation of the circuit is 828 W at bias current 233 A. Non-ideal, parasitic effects, sensitivity analyses, temperature and noise variation, current swing capability, and Monte Carlo analysis results are also provided. Compared to prior state-of-the-art works, the proposed CBTA-C APF has achieved the highest Figure of Merit value, which proves its superior performance.
Optimized High Resolution 3D Dense-U-Net Network for Brain and Spine Segmentation
(MDPI, 2019-02-15) Kolařík, Martin; Burget, Radim; Uher, Václav; Říha, Kamil; Dutta, Malay Kishore
The 3D image segmentation is the process of partitioning a digital 3D volumes into multiple segments. This paper presents a fully automatic method for high resolution 3D volumetric segmentation of medical image data using modern supervised deep learning approach. We introduce 3D Dense-U-Net neural network architecture implementing densely connected layers. It has been optimized for graphic process unit accelerated high resolution image processing on currently available hardware (Nvidia GTX 1080ti). The method has been evaluated on MRI brain 3D volumetric dataset and CT thoracic scan dataset for spine segmentation. In contrast with many previous methods, our approach is capable of precise segmentation of the input image data in the original resolution, without any pre-processing of the input image. It can process image data in 3D and has achieved accuracy of 99.72% on MRI brain dataset, which outperformed results achieved by human expert. On lumbar and thoracic vertebrae CT dataset it has achieved the accuracy of 99.80%. The architecture proposed in this paper can also be easily applied to any task already using U-Net network as a segmentation algorithm to enhance its results. Complete source code was released online under open-source license.
Universal Pseudo-Differential Filter Using DDCC and DVCCs
(Kaunas University of Technology, 2017-12-18) Sládok, Ondřej; Koton, Jaroslav; Herencsár, Norbert
In the paper, a universal preudo-differential second-order filter operating in voltage mode, where both input and output are differential, is presented. The circuit is formed by one differential difference current conveyor (DDCC), two differential voltage current conveyors (DVCCs), and five passive elements. The filter is characterized by high input impedance, minimum number of passive elements that are all grounded, and high common-mode rejection ratio (CMRR). The proposed filter structure is able to realize all five standard frequency filter responses. Non-ideal analysis has been performed by considering the real parasitic parameters of the active elements. The optimization of passive element values has been done in terms of minimal shift of the pole-frequency and to obtain the maximum stop-band attenuation of the high-pass filter response. Functionality is verified by simulations and experimental measurements using readily available integrated circuit UCC-N1B 0520.
Compact MOS-RC Voltage-Mode Fractional-Order Oscillator Design
(IEEE, 2017-09-04) Kartci, Aslihan; Herencsár, Norbert; Koton, Jaroslav; Psychalinos, Costas
A new voltage-mode fractional-order oscillator, employing in total 12 Metal-Oxide-Semiconductor (MOS) transistors, is introduced in this paper. The proposed circuit is composed of two operational transconductance amplifiers, two inverting voltage buffers, one resistor, and two fractional-order capacitors. Compared with the corresponding already introduced fractional-order oscillators, it offers the benefit of low transistor count and, therefore, simplicity of its structure. In addition, it offers the well-known advantages of fractional-order oscillators about the capability for achieving very low and high oscillation frequencies with reasonable component values. The behavior of the proposed oscillator has been numerically studied using the MATLAB program, while its performance has been evaluated by SPICE simulations, using TSMC 0.18 um Level-7 CMOS process parameters with ±1 V supply voltages.
Voltage Gain-Controlled Third-Generation Current Conveyor and its All-Pass Filter Verification
(IEEE, 2017-09-04) Herencsár, Norbert; Kartci, Aslihan; Koton, Jaroslav; Tsirimokou, Georgia; Psychalinos, Costas
The paper presents a new active building block (ABB) called minus-type voltage gain-controlled third-generation current conveyor (VGC-CCIII) in which the voltage gain between Y to X terminal can be controlled. The usefulness of the tunable feature in the presented ABB is demonstrated in current-mode {0.3rd; 0.5th; 0.7th; 1st}-order all-pass filter (APF) employing single VGC-CCIII, one capacitor, and one resistor. The theoretical results of the integer- and fractional-order APF are verified by SPICE simulations based on readily available IC OPA860 macromodel, which can also be used in experiments.

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