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ABSTRACT: This paper describes the design of a log-domain multiphase sinusoidal oscillator (MSO). The circuit is a direct realization of a first-order differential equation for obtaining the non-inverting and inverting lossy integrators. Each integrator comprises only a grounded capacitor and six transistors. The proposed MSO can be instantaneously controlled over wide frequency range by controlling the bias currents. The high-frequency of oscillation and oscillation condition can also be independently tuned which are indicated proposed MSO suitability in communications and high-frequency applications. The power consumption is obtained around 5.78mW at 100μA of bias current based on 2V single power supply. The oscillation frequency is controlled over four decades of frequency. The total harmonic distortion of four-phases (11.33MHz) is obtained around 1.12%.
Circuits and Systems (MWSCAS), 2011 IEEE 54th International Midwest Symposium on; 09/2011
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ABSTRACT: This paper presents a design of digital filter for digital hearing aids application. The structure of filter is consist a combination in parallel form of IIR (Infinite Impulse Response) a low-pass, a band-pass and a high-pass filter. This study shows an advantage of IIR filter can gives a good result in the low complexity digital hearing aids which leads to low hardware resources requirement and low power consumption for VLSI design. The filter coefficients of there IIR filter will obtained from the optimization procedure by genetic algorithm (GA.) The error between desired magnitude response and actual magnitude response will be minimized by GA. In order to achieve a capable of the best compensation for each hearing loss pattern. Finally, the design example and simulation results will show the accuracy of hearing loss compensation and optimal coefficients.
Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology (ECTI-CON), 2011 8th International Conference on; 06/2011
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ABSTRACT: This paper describes a new electronically tunable four inputs and single output voltage-mode universal biquadratic filter based on simple CMOS operational transconductance amplifiers (OTAs) and grounded capacitors. The proposed filter provides low-pass, high-pass, band-pass, band-stop and all-pass voltage responses at a high impedance input terminal, which enable easy cascadability. The circuit parameters ω<sub>o</sub> and Q can be orthogonally set the circuit component. The parameter ω<sub>o</sub> also offers an electronic control by adjusting the transconductance gain of the OTA. For realizing all the filter responses, no critical component matching condition is required and all the parameter sensitivities are low. PSPICE simulation results are performed to confirm the theoretical analysis.
Circuits and Systems (APCCAS), 2010 IEEE Asia Pacific Conference on; 01/2011
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ABSTRACT: This study describes the design of a multiphase sinusoidal oscillator (MSO) based on log-domain filtering concept. The circuit is a direct realisation of a first-order differential equation for obtaining the inverting and non-inverting low-pass filters. Each low-pass filter comprises only a grounded capacitor and four transistors. The proposed MSO can be instantaneously controlled over a very wide frequency range by controlling the current for the oscillation frequency and oscillation condition which indicates the proposed MSO's suitability in high-frequency applications. A validated bipolar junction transistor (BJT) model is used in SPICE simulation operated from a single power supply as low as 2.5'V. The oscillation frequency is controlled over four decades of frequency. The total harmonic distortions for three phase (11.5'MHz) and four phase (7'MHz) are, respectively, obtained around 2.4 and 2.2' which enables them to be fully integrated in telecommunication systems. The power consumption is around 5.5'mW for 100''A bias current. Moreover, experimental results of three-phase MSO are included.
IET Circuits Devices & Systems 10/2010; · 0.55 Impact Factor
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ABSTRACT: The design and implementation of web-based DICOM-format image archive, medical image compression and DICOM viewer system for teleradiology application which DICOM server was developed using software such as Borland Delphi 6.0, PHP and MySQL for image archive, image compression, image processing and image transmission. The system provides the following facilities: (1) DICOM-format image archive. (2) Medical Image Compression based on JPEG and JPEG2000. and (3) DICOM viewer. The results shown that (1) our system can also convert the image data both single frame and multiframes in normal or automatic DICOM process into the standard DICOM 3.0 format without altering the image data. (2) The resulting images are then compressed with two different techniques - JPEG and JPEG2000. The significant advantage of JPEG2000 over normal JPEG is that the error from JPEG2000 compression is smaller than the error from JPEG. Nevertheless, both methods share a similar mishap; when the compression ratio increases, they both generate more error than the processes on lower compression ratio. And (3) our system can open single frame and multiframes, each of which can exhibit information in .dcm file format with no distortion and digital image processing based on local contrast enhancement, adaptive interpolators techniques, colour transformation and cine loop. The system has been developed and provided medical image services over long distance which showed the usefulness of our approach.
SICE Annual Conference 2010, Proceedings of; 09/2010
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ABSTRACT: Located in Ladkrabang, Bangkok, The Earth Observation Center (EOC) of the Geo-Informatics and Space Technology Development Agency (GISTDA) is a ground station for receiving, managing, processing and archiving the Earth observation satellites data. The GISTDA EOC has two SAR data processing systems (SDPS) to support data processing from two SAR satellite constellations: RADARSAT and ALOS. This paper provides the overview of both SAR data processing systems including descriptions of the systems, data processing algorithms, architectures and functionality. The paper finally verifies the image quality characteristics of the example SAR data products generated by the two SDPS by comparing with the satellite operating agency's specifications.
Signal Processing and Its Applications (CSPA), 2010 6th International Colloquium on; 06/2010
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ABSTRACT: In this paper, we propose a new PAPR reduction by using the hybrid of partial transmit sequences (PTS) and cascade adaptive peak power reduction (CAPPR) methods with coded side information (SI) technique design by genetic algorithm (GA). These methods are used in an orthogonal frequency division multiplexing (OFDM) system. The OFDM employs orthogonal sub-carriers for data modulation. These sub-carriers unexpectedly present a large peak to average power ratio (PAPR) in some cases. A proposed reduction method consists of these two methods and realizes both advantages at the same time. In order to obtain the optimum condition on PTS for PAPR reduction, a quite large calculation cost must be demanded and thus it is impossible to obtain the optimum PTS. In the proposed method, by using the pseudo-optimum condition with a coded SI technique designed by GA, the total calculation cost becomes drastically reduced. In simulation results, the proposed method shows the improvement on PAPR and also reveals the high performance on bit error rate (BER) of an OFDM system.
Communications and Information Technology, 2009. ISCIT 2009. 9th International Symposium on; 10/2009
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ABSTRACT: In general, the image formats from radiological modalities are incompatible with the standard DICOM-format. Our system is developed to convert images into DICOM-format that are ready to implement in the medical teleradiological system. The system can process and record the image signal sent to the display unit in the single frame and multiframe image modes. The later mode keeps the set of images in windows bitmap file with .BMP file extension. The resulting images are then compressed with two different techniques - JPEG and JPEG2000. The significant advantage of JPEG2000 over normal JPEG is that the error from JPEG2000 compression is smaller than the error from JPEG. Nevertheless, both methods share a similar mishap; when the compression ratio increases, they both generate more error than the processes on lower compression ratio do. In addition, our system can also convert the image data in normal or automatic DICOM process into the standard DICOM 3.0 format without altering the image data. The final image data can then be used in any radiological modality.
ICCAS-SICE, 2009; 09/2009
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ABSTRACT: In this paper, we propose a new PAPR reduction using the hybrid of a partial transmit sequences (PTS) and an adaptive peak power reduction (APPR) methods with genetic algorithm (GA). These methods are used in an Orthogonal Frequency Division Multiplexing (OFDM) system. The OFDM employs orthogonal sub-carriers for data modulation. These sub-carriers unexpectedly present a large Peak to Average Power Ratio (PAPR) in some cases. In order to reduce PAPR, the sequence of input data is rearranged by PTS. The APPR method is also used to controls the peak level of modulation signals by an adaptive algorithm. A proposed reduction method consists of these two methods and realizes both advantages at the same time. In order to make the optimum condition on PTS for PAPR reduction, a quite large calculation cost must be demanded and thus it is impossible to obtain the optimum PTS. In the proposed method by using genetic algorithm, the total calculation cost becomes drastically reduced. The parameter for simulation used standard WLAN in IEEE 802.11a system. In simulation results, the proposed method shows the improvement on PAPR and also reveals the high performance on bit error rate (BER) of an OFDM system.
Innovative Technologies in Intelligent Systems and Industrial Applications, 2009. CITISIA 2009; 08/2009
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ABSTRACT: This paper presents a multiplierless Sobel edge detection filter structure based on the gradient of Gaussian lowpass filter concept. This concept is same as the idea that used for evaluation of Sobel edge detection kernels. The proposed Sobel edge detection filter structure consists of 4 sets of the so-called lowpass-type 2<sup>nd</sup> order 1-D DPF (discrete pascal filter) and the filter structure does not need any multipliers, only 14 adders are needed for realization. Consequently, the high efficiency multiplierless Sobel edge detector can be achieved.
Innovative Technologies in Intelligent Systems and Industrial Applications, 2009. CITISIA 2009; 08/2009
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ABSTRACT: The so-called generalized Pascal matrix is used for transforming a continuous-time (CT) linear system (filter) into a discrete-time (DT) one. This paper derives an explicit expression for a new generalized Pascal matrix called unified Pascal matrix from a unified first-order S-to-Z transformation model and rigorously proves the inverses for various first-order s -to- z transformations. After deriving a recurrence formula for recursively generating the inner elements of the unified Pascal matrix from its boundary elements, we also show that the recurrence formula leads to computationally unstable solutions for high-order systems due to the so-called catastrophic cancellation in numerical computation, but the unstable problem can be solved through partitioning the whole unified Pascal matrix into several small matrices (submatrices) and then using the recurrence formula to compute the submatrices individually from their boundary elements. This operation almost retains the same computational complexity while guarantees numerically stable solutions. Moreover, an interesting property of the unified Pascal matrix is proved.
IEEE Transactions on Signal Processing 07/2009; · 2.63 Impact Factor
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ABSTRACT: In this paper, a new electronically tunable current-mode universal filter with three inputs and single output employing only two translinear current conveyors and two grounded capacitors is presented. The proposed configuration provides lowpass, bandpass, highpass, bandstop and allpass current responses by choosing appropriate input signals without any component matching conditions, all at a high impedance output which enables easy cascading in the current-mode operation. The filter also offers independent electronic control of the natural frequency (omega<sub>o</sub>) and the quality factor (Q) through adjusting of the bias current and the current gain of the CCCII. The parameter sensitivities are all very low and the structure is very suitable for IC implementation. The characteristics of the proposed circuit are simulated using PSPICE to confirm the theory.
Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, 2009. ECTI-CON 2009. 6th International Conference on; 06/2009
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ABSTRACT: A current-controlled current-mode multiphase sinusoidal oscillator employing translinear current conveyors is presented. The proposed oscillator circuit, which uses only one translinear current conveyor and one grounded capacitor for each phase and can generate arbitrary n signals which are equal in amplitude and equally spaced in phase. The oscillation frequency of each phase is independently tuned through bias current while the oscillation condition is controlled by current gain of current conveyor. The proposed circuit also enjoys having simple structure, very low-component count and it is highly suitable for IC implementation.
Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, 2009. ECTI-CON 2009. 6th International Conference on; 06/2009
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ABSTRACT: A new single-element-controlled current-mode quadrature oscillator circuit using second-generation current conveyors (CCIIs) is presented. The proposed oscillator is consisted of two CCIIs, two grounded capacitors and three grounded resistors. The circuit is beneficial to monolithic integrated circuit implementation by the use of grounded passive components. In addition, a new current-controlled sinusoidal oscillator using two second-generation current-controlled conveyors (CCCIIs), two grounded capacitors and one grounded resistor can be achieved by replacing CCIIs and resistors series at X terminals with CCCIIs. The oscillation frequencies of the CCII-based can be controlled by a grounded resistor while the CCCII-based can be controlled by a bias current. The realized of both circuits provide four quadrature current outputs at high output impedance nodes. PSPICE simulation results that confirm the theoretical predictions are given.
Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, 2009. ECTI-CON 2009. 6th International Conference on; 06/2009
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ABSTRACT: A high input impedance electronically tunable voltage-mode biquadratic filter with single input and three outputs using four simple CMOS operational transconductance amplifiers and two grounded capacitors is proposed. The proposed filter provides low-pass, band-pass and high-pass voltage responses at a high input impedance terminal, which enables easy cascadability of the voltage circuit. Also, the parameters omega<sub>o</sub> and Q can be set orthogonally by adjusting the circuit components. For the realizing of all the filter responses, no critical matching condition is required, on inverting-type input signal is imposed and all the incremental parameter sensitivities are low. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory. The band-stop and all-pass responses can also be obtained by interconnection of relevant output voltages with summer circuits.
Instrumentation and Measurement Technology Conference, 2009. I2MTC '09. IEEE; 06/2009
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ABSTRACT: A voltage-mode versatile multifunction filter with four inputs and three outputs biquadratic filter based on simple CMOS operational transconductance amplifiers (OTAs) is presented. By appropriately connecting the input and output terminals, the proposed circuit can work as either a single-input multiple-output (SIMO) or a multiple-input single-output (MISO) filter without changing the circuit topology. When the circuit functions as a SIMO filter, it provides bandpass (BP), lowpass (LP) and bandstop (BS) voltage responses with grounded capacitors. When it functions as a MISO filter, the circuit can realize all the standard non-inverting and inverting second-order filter functions. The parameters omega<sub>0</sub> and Q can be set orthogonally by adjusting the circuit components. For realizing all the filter responses, no critical matching condition is required, no inverting-type input signal is imposed and all the incremental parameter sensitivities are low. The simulation results confirm the theoretical analysis.
Signal Processing & Its Applications, 2009. CSPA 2009. 5th International Colloquium on; 04/2009
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ABSTRACT: A variable fractional delay (VFD) filter is widely used in applications such as symbol timing recovery, arbitrary sampling rate conversion and echo cancellation. This paper presents an implementation of variable fractional delay filter on FPGA. The implementation utilizes an efficient structure so called Taylor structure. The main advantage of this structure is to reduce number of multiplier and adder when compared with Farrow structure or modified Farrow structure. The result of implementation will be reported as throughput and area utilization.
Signal Processing & Its Applications, 2009. CSPA 2009. 5th International Colloquium on; 04/2009
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ABSTRACT: A gigahertz analog multiplier based on OTA and squaring is proposed. The multiplier has gigahertz frequency response is suitable to use in communication system. The circuit is based on 0.18 mum CMOS technology simulated using PSPICE level 7. This technique provides; wide dynamic range, GHz-bandwidth response and low power consumption. The proposed circuit has been simulated with PSPICE and achieved -3 dB bandwidth of 3.96 GHz. The total power dissipation is 0.588 mW with plusmn1 V power supply voltages..
Intelligent Signal Processing and Communications Systems, 2008. ISPACS 2008. International Symposium on; 03/2009
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ABSTRACT: A current-mode quadrature oscillator using two operational transconductance aTmplifiers (OTAs) and two grounded capacitors is presented. The circuit provides two high output impedance current sources with 90deg phase difference. The oscillation frequency can be controlled electronically by adjusting the bias current/voltage of OTAs. The proposed circuit employs only grounded capacitors and requires no resistors. The use of only grounded capacitors is ideal for IC implementation. The proposed structure is eminently suitable for implementation in both bipolar and CMOS technologies. The theoretical results are verified by PSpice simulation.
Intelligent Signal Processing and Communications Systems, 2008. ISPACS 2008. International Symposium on; 03/2009
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ABSTRACT: An active-only devices current-mode universal filter using the biquadratic transfer function is proposed. The proposed circuit is realized based on minimized active-only components count without external passive elements. The electronic resistors are used instead of 2 OTAs. The different kinds of filter function such as lowpass, highpass, bandpass and band-reject response can be obtained without changing circuit topology. A quadrature oscillator can also be easily modified without changing circuit topology. The proposed circuit is realized by using 4 MOS transistors, 3 OTAs, and 2 Opamps. The parameters omega<sub>P</sub> and Q<sub>P</sub> can be electronically tuned independently through adjusting the transconductance gains of the OTAs. The simulation results are given by PSpice.
Intelligent Signal Processing and Communications Systems, 2008. ISPACS 2008. International Symposium on; 03/2009
