• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.7
• /
• pp.661-668
• /
• 2004

A novel method to reject the spurious signals which are occurred at Weaver-type low-IF transmitter was proposed in this paper. The spurious signals are generated by the gain and phase imbalances of I/Q channel or imperfect characteristics of 90$^{\circ}$ phase shifter in local oscillator for I/Q channel source. By deriving the gain and phase-based functions from RF spurious signal with the channel imbalance information, the lie channel imbalances were deduced as functions with magnitude and sign dependent on I/Q channel imbalance degree. The proposed method compensates the estimated I/Q channel imbalances by correlation values between the down-converted signal obtained by squaring the output signal itself using a simple mixer and the modified baseband signal. By comparing two signals after A/D conversion, the magnitude and sign of each type of imbalances can be determined separately and simultaneously. Based on the I/Q channel imbalance compensation, the spurious signals can be reduced by adjusting the gain and phase values of I or Q channel signal. The way to estimate the channel imbalances of the up-conversion mixer was presented and verified by using theoretical derivations and computer simulations.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.5 no.3
• /
• pp.210-219
• /
• 2005

We report on a low-cost V-band wireless transceiver with no use of any local oscillator in the receiver block using a self-heterodyne architecture. V-band millimeter-wave monolithic IC (MMIC) modules were developed to demonstrate the wireless transceiver using coplanar waveguide (CPW) and GaAs PHEMT technologies. The MMIC modules such as the MMIC low noise amplifier (LNA), medium power amplifier (MPA) and the up/down-mixer were installed in the transceiver system. To interface the MMIC chips with the component modules for the transceiver system, CPW-to-waveguide fin-line transition modules of WR-15 type were designed and fabricated. The fabricated LNA modules showed a $S_{21}$ gain of 8.4 dB and a noise figure of 5.6 dB at 58 GHz. The MPA modules exhibited a gain of 6.9 dB and a $P_{1dB}$ of 5.4 dBm at 58 GHz. The conversion losses of the up-mixer and the down-mixer module were 14.3 dB at a LO power of 15 dBm, and 19.7 dB at a LO power of 0 dBm, respectively. From the measurement of V-band wireless transceiver, a conversion gain of 0.2 dB and a $P_{1dB}$ of 5.2 dBm were obtained in the transmitter block. The receiver block showed a conversion gain of 2.1 dB and a $P_{1dB}$ of -18.6 dBm. The wireless transceiver system demonstrated a successful data transfer within a distance of 5 meters.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.5
• /
• pp.747-755
• /
• 2009

The feed resource for animals is a major cost determinant for profitability in livestock production enterprises, and thus any effort at improving the efficiency of feed use will help to reduce feed cost. Feed conversion ratio, expressed as feed inputs per unit output, is a traditional measure of efficiency that has significant phenotypic and genetic correlations with feed intake and growth traits. The use of ratio traits for genetic selection may cause problems associated with prediction of change in the component traits in future generations. Residual feed intake, a linear index, is a trait derived from the difference between actual feed intake and that predicted on the basis of the requirements for maintenance of body weight and production. Considerable genetic variation exists in residual feed intake for cattle and pigs, which should respond to selection. Phenotypic independence of phenotypic residual feed intake with body weight and weight gain can be obligatory. Genetic residual feed intake is genetically independent of its component traits (body weight and weight gain). Genetic correlations of residual feed intake with daily feed intake and feed conversion efficiency have been strong and positive in both cattle and pigs. Residual feed intake is favorably genetically correlated with eye muscle area and carcass weight in cattle and with eye muscle area and backfat in pigs. Selection to reduce residual feed intake (excessive intake of feed) will improve the efficiency of feed and most of the economically important carcass traits in cattle and pigs. Therefore, residual feed intake can be used to replace traditional feed conversion ratio as a selection criterion of feed efficiency in breeding programs. However, further studies are required on the variation of residual feed intake during different developmental stage of production.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.7
• /
• pp.944-950
• /
• 1993

Diodes and GaAs have been commonly used in a mixer design until recently. However, diodes are not preferred to use at the front-end of DBS receiver due to the conversion loss large noise. HEMT has larger conversion gain and better noise characteristics comparing with GaAs MESFET. This paper describes the design procedure, structure, and performance of a mixer, utilizaing HEMT designed by OKI Co. . A mixer configuration in which the local oscillator(LO) signal is applied to the gate is used. When the LO power is 0.01 dBm, the conversion gain of 3.7dB is obtained at IF and the 3 dB bandwidth is 400MMz.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.4 no.3
• /
• pp.183-189
• /
• 2009

In this paper, we propose RF front-end architecture using hybrid conversion method to receive broadband signal. The validity is verified by design, fabrication and experiment. The proposed RF front-end architecture due to up-conversion block improves the deficiency of performance deterioration to be generated through harmonic signal and image signal conversion in the conventional RF front-end, and improves the deficiency of the complexity that is from to adopt a multiple local oscillators for the generation of wideband LO signal in the conventional RF front-end by applying the principle that tuning bandwidth is multiplied at sub-harmonic mixer. Manufactured circuits satisfy the deduced design specification and target standard with gain above 80 dB, noise figure below 6.0 dB and IIP3 performance above -5.0 dBm for the condition of the minimum gain in RF front-end.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.2
• /
• pp.81-89
• /
• 1999

Among various wavelength conversion technologies, that using the cross-gain modulation in laser diode makes it possible to deal with the high speed signal quite simply and efficiently. In this paper, presented was the applicability of an improved time-domain large-signal dynamic model as a CAD tool to analyzed the characteristics of SSGDBR(Superstructure Grating Distributed Bragg Reflector) laser diodes used for wavelength converters. Using this model, it was shown that this kind of wavelength converter can provide the widely tunable wavelength conversion of the high speed data above 10 Gbps. We also investigated the effect of input optical power and the bias current on the characteristics of the device such as extinction ration and eye diagram. The modeling results show very similar trend to the experimental reports.

• Journal of Animal Science and Technology
• /
• v.47 no.2
• /
• pp.293-304
• /
• 2005

This experiment was carried out to investigate effects of honeybee venom treatment on the body weight gain, feed conversion and growth rate' in pigs. One hundred twenty nine piglets(LY) from 12 sows were allocated into two groups; honeybee venom-treated group (66 piglets from 6 sows) and non-treated control group (63 piglets from 6 sows). Natural honeybee venom was administrated at 0, 3, 14, 30, and 74 days after birth. The acupoints were Hai-men(ST-25), Du-kou(CV-8) and liao-chao(GV-I) points at 0 day, the regions of castration and tail ampution at 3 days, liao-chao(GV-1) and Bai-hui(GV-20) points at 14(weaning), 30(move into piglet stall) and 74(move into grower stall) days after birth. Control group was injected 1 ml of saline to the same site. Average body weight at 150 days after birth was 98.44 kg in bee venom treated group and 86.24 kg in control group, respectively. Average body weight of treated group was significantly increased by 14.15%(P < 0.0001). Average daily gain of bee venom treated group and control group were 649 g and 569 g, respectively, increased by 14.06%(P< 0.0001). Feed conversion of the treated group was 2.21 and control group was 2.49, increased by 11.25% in control group(P < 0.001). Survival rate at weaning was 95.5 % in treated group and 92.0% in control group, at growing(74 days after birth) was 92.4% in treated group and 85.7% in control group and survival rate at finishing(l50 days after birth) was 89.5 % and 79.4 %, respectively. Collecting together, the results in this study showed that growth performance and feed conversion were increased by treatment of natural honeybee venom to pigs. These results suggested that the treatment of bee venom could be used effectively for the increase productivity of livestock industry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.9 no.4
• /
• pp.542-551
• /
• 1998

In this study, a method of error compensation for channel gain imbalance, phase imbalance and local oscillator leakage in the modulator of frequency direct conversion is suggested. The compensation of channel imbalance can be carried out by using the received power after transmitting test signal. By applying this method, the phase imbalance conversion with frequency can be easily compensated since this method is rarely affected by the transmission channel. It is confirmed that the algorithm proposed in this study(iteration coefficient=11) converges faster than conventional algorithm(iteration coefficient=43). From the numerical results, the DC-offset, channel gain, phase imbalance compensation coefficient and iteration number converges into($f_1$=0.0199999, $f_2$=-0.050001, $C_{22}$=0.9133, $C_{12}$=-0.0524, N=13) when the local oscillator leakage is not considered. However, it converges into($f_1$=-0.02, $f_2$=-2.2476, $C_{22}$=0.9133, $C_{12}$=-0.0524, N=16) when the local oscillator leakage is considered.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.2
• /
• pp.100-105
• /
• 2010

In this paper, a FM radio receiver integrated circuit has been developed based on $0.5{\mu}m$ CMOS process for Zero-Crossing FM demodulator over the 88MHz to 108MHz band. The receiver is designed with the low-IF architecture, and includes Low Noise Amplifier(LNA), Down-Conversion Mixer, Phase Locked Loop(PLL), IF LPF, and a comparator. The measured results of the LNA and Mixer show that the conversion gain of 23.2 dB, the input PldB of -14 dBm, and the noise figure of 15 dB. The measured analog block of the LPF and comparator show the voltage gain of over 89 dB, and the IF LPF can configure the passband from 600KHz to 1.3MHz with 100KHz step through the internal control register banks. The designed FM radio receiver operates at 4.5V with the total current consumption of 15.3mA, so the total power consumption is about 68.85mW. The commercial FM radio has been successfully received.

• The Journal of the Korea Contents Association
• /
• v.6 no.4
• /
• pp.1-10
• /
• 2006

In this paper, a broadband RF module is designed and tested for 2.4GHz band applications. The RF module is composed of a low noise amplifier (LNA) with a three stage amplifier, a single ended gate mixer, matching circuits, a hairpin line band pass filter and a Chebyshev low pass filter to convert the radio frequency (RF) into the intermediate frequency (IF). The LNA has a high gain and stability, and the single ended gate mixer has a high conversion gain and wide dynamic range. In the analysis of the broadband RF module, the composite harmonic balance technique is used to analyze the operating characteristics of an RF module circuit. The RF module has a 55.2dB conversion gain with a 1.54dB low noise figure, $-120{\sim}-60dBm$ wide RF power dynamic range, -60dBm low harmonic spectrum and a good isolation factor among the RF, IF, and local oscillator (LO) ports.