Yuwono S.,KAIST |
Han S.-K.,KAIST |
Yoon G.,KAIST |
Cho H.-J.,SW SoC Convergence Research Laboratory |
IET Circuits, Devices and Systems | Year: 2014
The authors report the development of an on-chip 500 MHz reference clock generator as a part of a clock manager for a field-programmable gate array. The generator is implemented in the form of an all-digital frequency locked loop (ADFLL) in architecture of low complexity and high modularity. For the development of the ADFLL, they propose a new circuit that employs two under-sampled 1-bit δ∑ frequency-to-digital converters to convert a frequency difference into a proportional distributed pulsewidth. By the combination of the proposed circuit with a conventional phase-and-frequency detector, a frequency comparator is implemented and can indicate its two input frequency conditions, that is, (i) equal to, (ii) lower than or (iii) higher than. The ADFLL which adopts the proposed frequency comparator is implemented in a 90 nm CMOS technology. Consuming 2.64 mW from a 1.2 V supply, the ADFLL shows about 50 μs of locking time at the frequency accuracy of 99.2% while operating at 500 MHz and being driven by a 10 MHz reference clock. © The Institution of Engineering and Technology 2014.
Nguyen T.D.,Chonnam National University |
Kim J.H.,Chonnam National University |
Kim S.H.,Chonnam National University |
Yang H.J.,Chonnam National University |
And 3 more authors.
ETRI Journal | Year: 2012
A novel interaction method for mobile phones using their built-in cameras is presented. By estimating the path connecting the center points of frames captured by the camera phone, objects of interest can be easily extracted and recognized. To estimate the movement of the mobile phone, corners and corresponding Speeded-Up Robust Features descriptors are used to calculate the spatial transformation parameters between the previous and current frames. These parameters are then used to recalculate the locations of the center points in the previous frame into the current frame. The experiment results obtained from real image sequences show that the proposed system is efficient, flexible, and able to provide accurate and stable results. © 2012 ETRI.
Hyoung C.-H.,SW SoC Convergence Research Laboratory |
Kang S.-W.,SW SoC Convergence Research Laboratory |
Park S.-O.,KAIST |
Kim Y.-T.,Chosun University
ETRI Journal | Year: 2012
This paper presents a transceiver module for human body communications whereby a spread signal with a group of 64 Walsh codes is directly transferred through a human body at a chip rate of 32 Mcps. Frequency selective digital transmission moves the signal spectrum over 5 MHz without continuous frequency modulation and increases the immunity to induced interference by the processing gain. A simple receiver structure with no additional analog circuitry for the transmitter has been developed and has a sensitivity of 250 μV pp. The high sensitivity of the receiver makes it possible to communicate between mobile devices using a human body as the transmission medium. It enables half-duplex communication of 2 Mbps within an operating range of up to 170 cm between the ultra-mobile PCs held between fingertips of each hand with a packet error rate of lower than 10 -6. The transceiver module consumes 59 mA with a 3.3 V power supply. © 2012 ETRI.
Jeong M.J.,Chosun University |
Park K.H.,Chosun University |
Kim J.M.,Chosun University |
Hwang J.-H.,SW SoC Convergence Research Laboratory |
And 2 more authors.
Electronics Letters | Year: 2012
Presented is a feasibility study on power transmission using magnetic coupling between devices in a body area network. The effects of transmission distance and body movement on transmission efficiency were investigated. The measurement results show a maximum transmission efficiency of 46.2 at a distance of 10cm, and this result presents the possibility of transmitting power in a body area network with high efficiency. © 2012 The Institution of Engineering and Technology.