• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.4
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• pp.267-272
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• 2010

In this paper, a Gm-C LPF utilizing common-mode feedforward (CMFF) CMOS inverter type operational transconductance amplifier (OTA) has been designed and verified by circuit simulations. The CMFF CMOS inverter OTA was optimized for wide input linearity and low current consumption using a standard 0.18 ${\mu}m$ CMOS process; gm of 100 ${\mu}S$ and current of 100 ${\mu}A$ at supplied voltage of 1.3 V. Using this optimized CMFF CMOS inverter type OTA, an elliptic 5th order Gm-C LPF for GPS specifications was designed. Gain and frequency tuning of the LPF was done by changing the internal supply voltages. The designed Gm-C LPF gave pass-band ripple of 1.6 dB, stop-band attenuation of 60.8 dB, current consumption of 0.60 mA at supply voltage of 1.2 V. The gain and frequency characteristics of designed Gm-C LPF was unchanged even though the input common-mode voltage is varied.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.12 s.354
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• pp.81-88
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• 2006

This paper describes a new linear operational transconductance amplifier (OTA). To improve the linearity of the OTA, we employ a mobility compensation circuit that combines the transistor paths operating at the triode and subthreshold regions. The common-mode control schemes consist of a common-mode feedback (CMFB) and common-mode feedforward (CMFF). The circuit enhances linearity of the transconductance (Gm) under the wide input voltage swing range. The proposed OTA shows ${\pm}1%$ Gm variation and the total harmonic distortion (THD) of below -73dB under the input voltage swing range of ${\pm}1.1V$. The OTA is implemented using a $0.35{\mu}m$ n-well CMOS process under 3.3V supply.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.135-145
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• 2013

One of the words that describe unique features of human beings is "Homo Ludens (Playing Man)". As humans enjoy abundant and prosperous lives and the quality of life is further improved, play is increasingly becoming a central value of human life. As part of play, ocean leisure is getting popular these days, and in turn demands for ocean leisure-related products in Korea, most of which are dependent on foreign markets, are growing. Therefore, it is required that local companies are quick to turn their eyes on the fast developing market. This research aims to help develop a design concept for bodyboard, more suitable for the domestic market, by analyzing products and reflecting customers' needs. The findings of this study are as follows: first, it is desirable that the target of bodyboard in domestic market is young people aged between 14 and 29 and its price ranges from 40,000 to 100,000 won; second, a tube-type bodyboard is appropriate for beaches in Korea mostly with small and gentle waves, as also shown in a survey that over 65% of those surveyed prefer a tube-type bodyboard, and lastly, the CMFF (Color, Material, Form, and Function) strategy was newly developed in this study in order to create new concept bodyboards.