Search results

The purpose of this paper is to design a voltage reference circuit for current source of radio frequency integrated circuit blocks. The voltage reference circuit is called voltage for current source (VCS).

The circuit concept is discussed. A voltage‐controlled oscillator (VCO) and buffer circuit together with VCS circuit are built to prove the concept. Though the VCS circuit employs no array of diode like standard bandgap circuit, it still employs the concept of proportional to absolute temperature (PTAT) and a complement to absolute temperature (CTAT) elements. The integrated VCO, together with VCO core and VCO buffer circuits, are designed for W‐CDMA application particularly for the demodulator section. All circuits are built in f_T=45 GHz SiGe BiCMOS process.

At 760 MHz the power consumption for core circuit is 0.6 and 3.3 mA for VCO buffer amplifier. The fabricated VCO circuit together with VCO buffer was tested and measured with VCO output of −6 dBm at 760 MHz with variation of 0.1 dBm across −40°C to 85°C.

A voltage reference circuit which is derived from PTAT and CTAT current generators is presented. The circuit is capable of providing a constant current across absolute temperature or a current PTAT.

The purpose of this paper is to present the high-frequency performance of 0.13-μm n-type metal-oxide-semiconductor (NMOS) transistors with various multi-finger configurations for implementation in millimeter-wave (mm-wave) frequency.

A folded-like double-gate transistor layout is designed to enable the transistor to work in the mm-wave region. Different sizes of transistors with variation in finger width (W_F) and number of fingers (N_F) were fabricated to determine the optimum size of the transistor. The extrinsic parasitic elements of selected transistors were extracted and investigated. The radio frequency (RF) performance of these samples were then analyzed and compared.

The proposed layout performed well with the highest maximum oscillation frequency (f_max) achieved at 122 GHz. Based on the comparison done, the optimum W_F obtained for the layout is at 2.0 μm. It is found that the extrinsic parasitic capacitance is more dominant than the parasitic resistance in affecting the f_max. In s-parameter analysis, it is observed that the transistor with the least N_F has smaller variance in small-signal gain throughout the measurement frequency. The maximum stable gain for the samples is also found to be roughly similar and independent of N_F.

A new layout structure for an NMOS transistor that works in mm-wave frequency is proposed. Experimental analyses presented here cover for both N_F and W_F, unlike others which focus on either N_F or W_F only.

The purpose of this paper is to evaluate subjectivity issue, particularly sensitivity variance and fatigue effect, in human sensory evaluation, as well as review the feasibility of human-independent quality system, using E-tongue and E-nose.

The sensitivity level is evaluated by measuring the threshold of Acesulfame-K, while the fatigue effect is evaluated by measuring the accuracy level of evaluation through the time. The experiment was administered to six trained sensory panelists.

The experiment result shows that each panelist has a different level of sensitivity and tendency in evaluating samples containing Acesulfame-K. Furthermore, by simulating the panelists’ daily inspection, the fatigue effect is also found in one out of six panelists. The use of E-nose and E-tongue, may eliminate the subjectivity issue, supporting the development of human error-free quality system.

The research findings indicate the needs of human substitution-built into the quality system to avoid both of subjectivity and error judgment while defining the products quality. However, the small numbers of panelists as well as the unvalidated substitute instruments application in the target workcenter were the main limitation of this study. Human-independent quality system could be applied only when the instruments have been calibrated to human response in perceiving taste and odor.

The research finding supports the theory of human panels’ tradeoffs in a sensory analysis in terms of sensitivity level variance and fatigue. It has provided additional contributions to the existing theories as well as developed effective strategies for the development of the human-independent quality system.

The purpose of this paper is to provide a better understanding of the development of intelligent agriculture (IA) in China, which is an important tendency in advancing the agricultural productivity in the coming era.

Considering publications as featured evidence of an emerging phenomenon, the authors review publications of IA. Specifically, the use of term, definition and examples of IA, both English and Chinese literature, and government policies of China are all reviewed. Additionally, the authors use basic statistical and thematic analysis to help synthesizing the literature and drawing conclusions. Findings from various sources of publications supplement with each other.

IA in China has shown three main characteristics: unbalanced geographic distribution, an early stage of the trend and attention mainly focused on a limited range of technologies. Compared with the development of IA in other countries, such as Japan, India and the USA, featured with diversified properties, similarities and differences of IA development in China and in other countries are also discussed.

This general review contributes by uncovering the emergence of IA, identifying its general definition with a comprehensive set of practical examples and pointing out the present characteristics and problems of IA development in China. The general review provides a necessary summary for the policy makers and researchers to have a systematic understanding of IA and better promote its future development. At last, the paper calls for a process-based strategy with different goals at different stages, a sustainable mechanism coordinated by multiple participants, and a localized consideration for relevant policy making.