• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.9
• /
• pp.68-73
• /
• 2009

This paper presents an easily modifiable structure of a serial peripheral interface (SPI) that is suitable for efficient testing of CMOS RF integrated circuits. The proposed SPI Is designed so that the address size and the accompanying software can be easily adjusted and modified according to the requirements and complexity of RF IC's under development. The hardware architecture and software algorithm to achieve the flexibility are described. The proposed SPI is fabricated in $0.13{\mu}m$ CMOS and successfully verified experimentally with a 2.7GHz fractional-N delta-sigma frequency synthesizer as a device under test.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.4
• /
• pp.483-491
• /
• 2012

It is expected that, in the future, DC power service will be widely used for photovoltaic home power generation systems, since DC consuming devices are ever increasing. Instead of using multiple converters to convert DC to AC and then AC to DC, the power service could solely be based on DC. This would eliminate the need for converters, reducing the cost, complexity, and possibly increasing the efficiency. However, configuration of direct DC power service with mechanical contacts can cause spark voltage or an electric shock when the switch is turned on and off. To solve these problems, in this paper, a contactless power supply for a DC power service that can transfer electric power produced by photovoltaics to the home electric system using magnetic coupling instead of mechanical contacts has been proposed. The proposed system consists of a ZVS boost converter, a half-bridge LLC resonant converter, and a contactless transformer. This proposed contactless system eliminates the use of DC switches. To reduce the stress and loss of the boost converter switching devices, a lossless snubber with coupled inductor is applied. In this paper, a switching frequency control technique using the contactless voltage sensing circuit is also proposed and implemented for the output voltage control instead of using additional power regulators. Finally, a prototype consisted of 150W boost converter has been designed and built to demonstrate the feasibility of the proposed contactless photovoltaic DC power service. Experimental results show that 74~83% overall system efficiency is obtained for the 10W~80W load.

• Journal of Korea Society of Industrial Information Systems
• /
• v.22 no.5
• /
• pp.17-24
• /
• 2017

Recently Deep-learning, Technologies using Large or Deep Artificial Neural Networks, have Shown Remarkable Performance, and the Increasing Size of the Network Contributes to its Performance Improvement. However, the Increase in the Size of the Neural Network Leads to an Increase in the Calculation Amount, which Causes Problems Such as Circuit Complexity, Price, Heat Generation, and Real-time Restriction. In This Paper, We Propose and Test a Method to Reduce the Number of Network Connections by Effectively Pruning the Redundancy in the Connection and Showing the Difference between the Performance and the Desired Range of the Original Neural Network. In Particular, we Proposed a Simple Method to Improve the Performance by Re-learning and to Guarantee the Desired Performance by Allocating the Error Rate per Layer in Order to Consider the Difference of each Layer. Experiments have been Performed on a Typical Neural Network Structure such as FCN (full connection network) and CNN (convolution neural network) Structure and Confirmed that the Performance Similar to that of the Original Neural Network can be Obtained by Only about 1/10 Connection.

• The KIPS Transactions:PartA
• /
• v.11A no.1
• /
• pp.81-88
• /
• 2004

In this paper, we designed the outer encoder/decoder for the terrestrial DMB that is an advanced digital broadcasting standard, implemented, and verified by using ALTERA FPGA. In the encoder part, it was created the parity bytes (16 bytes) from the input packet (188by1e) of MPEG-2 TS and the encoded data was distributed output by the convolutional interleaver for Preventing burst errors. In the decoder part, It was proposed the algorithm that detects synchronous character suitable to DMB in transmitted data from the encoder. The circuit complexity in RS decoder was reduced by applying a modified Euclid's algorithm. This system has a capability to correct error of the maximum 8 bytes in a packet. After the outer encoder/decoder algorithm was verified by using C language, described in VHDL and implemented in the ALTERA FPGA chips.

• Journal of Power Electronics
• /
• v.18 no.5
• /
• pp.1545-1554
• /
• 2018

This paper proposes a modified control strategy to improve the performance of three-phase four-leg shunt active power filters (APFs) for the compensation of three phase unbalanced loads. Unbalanced current cannot be obtained accurately by a harmonic detector due to the lower frequency. The proposed control strategy eliminates conventional harmonic detectors by directly regulating the source current. Therefore, the computational complexity is greatly reduced and the performance of the APF is improved. A mathematic model has been developed based on the source currents. The corresponding controllers have been designed based on the sinusoidal internal model principle. The proposed control strategy can guarantee excellent compensation performance and stable operation after an extreme disturbance such as a short circuit fault. In addition, the proposed technique can selectively compensate specific harmonics. A 50kVA prototype APF is implemented in the laboratory to validate the feasibility and performance of the proposed control strategy.

• Journal of KIISE:Computer Systems and Theory
• /
• v.31 no.1_2
• /
• pp.1-9
• /
• 2004

The important arithmetic operations over finite fields include exponentiation, division, and inversion. An exponentiation operation can be implemented using a series of squaring and multiplication operations using a binary method, while division and inversion can be performed by the iterative application of an AB$^2$ operation. Hence, it is important to develop a fast algorithm and efficient hardware for this operations. In this paper presents new bit-serial architectures for the simultaneous computation of multiplication and squaring operations, and the computation of an $AB^2$ operation over $GF(2^m)$ generated by an irreducible AOP of degree m. The proposed architectures offer a significant improvement in reducing the hardware complexity compared with previous architectures, and can also be used as a kernel circuit for exponentiation, division, and inversion architectures. Furthermore, since the Proposed architectures include regularity and modularity, they can be easily designed on VLSI hardware and used in IC cards.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.2
• /
• pp.397-401
• /
• 2005

In this paper, we have developed a frequency mixer which can be used as a microwave phase conjugator in the retrodirective array antenna. The retrodirective array, which can reflect the incident wave retrodirertively back to the source direction without any priori information, requires phase conjugators to achieve the phase change of 180 degrees for the incoming signal. frequency mixers can efficiently serve as phase conjugators. The circuit topology is of the 2-port structure to avoid the complexity of LO and Rf signal combination and matching circuits, using a pseudomorphic HEU device. The operating frequencies are 4.0 CHz, 2.01 CHz, and 1.99 CHz for LO, RF, and If signals, respectively. Conversion loss is measured to be -ldB and 1-dB compression point -l5 dBm at the LO power of -10 dBm.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.1
• /
• pp.97-103
• /
• 2018

In satellite communication, modulated beacon signal is spreaded by gold sequence and the modulated beacon is transmitted via linear phase modulation. Due to the difference in characteristics of the satellite and the receiver on the ground, frequency offset (FO) occurs. An existing modulated beacon receiver is a method of synchronizing the frequency of a modulated beacon signal using FFT(Fast Fourier Transform), which not only increases the delay and complexity in terms of system implementation but also has a separate circuit for compensating the phase difference due to FO and phase offset from FFT points. In order to overcome this problem, this paper proposes and analyzes a scheme for compensating and demodulating the coarse FO and phase offset at one time using the 2-phase shaped characteristics of the modulated beacon signal. Also, through the simulation, the modulation index suitable for the proposed method is analyzed and the appropriate cumulative number is also analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.2 s.93
• /
• pp.134-138
• /
• 2005

In this paper, we have developed a new type of the microwave phase conjugator for the active retrodirective antenna array. The circuit topology is consisted of a 2-port structure to avoid the complexity of LO and RF signal combination and matching, using the cascade connection of two single-ended mixers. The operating frequencies are 4.0 GHz, 2.01 GHz and 1.99 GHz for LO, RF, and IF, respectively. Conversion loss is measured to be -7 dB and 1-dB compression point 15 dBm with the LO power of 9 dBm. For the most important parameter, the isolation between RE leakage and IF signal is as high as 25 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.11 s.102
• /
• pp.1106-1113
• /
• 2005

This paper presents a dual-band mixer for multi-standards of IEEE 802.1la/b/g using a single local oscillator, so as to improve the defects of legacy systems. Those systems have duplicate local oscillators and mixers to handle dual band signals, increasing complexity of system and power loss. The proposed circuit shows 11.6 dB, 16.8 dB of conversion loss and 8.77 dBm, 12.5 dBm of IIP3(Input 3rd Intercept Point) for respective bands when the two RF inputs of 2.452 and 5.260 GHz are down-converted to the identical 356 MHz If frequency. The RF-LO isolations are measured 36 dB, 41 dB at each frequencies and over 50 dB of LO-IF isolations are achieved at all cases.