A New Approach for Built‐in Self‐Test of 4.5 to 5.5 GHz Low‐Noise Amplifiers

This paper presents a low‐cost RF parameter estimation technique using a new RF built‐in self‐test (BIST) circuit and efficient DC measurement for 4.5 to 5.5 GHz low noise amplifiers (LNAs). The BIST circuit measures gain, noise figure, input impedance, and input return loss for an LNA. The BIST circuit is designed using 0.18 μm SiGe technology. The test technique utilizes input impedance matching and output DC voltage measurements. The technique is simple and inexpensive.     

Measurement of the required cross-polar protection ratio in G-PALTV FM satellite transmissions planning

A measurement campaign using live TV broadcast satellite signals and receiving commercial equipment has been carried out to study the required cross-polar protection ratio at the receiving antenna in satellite transmission planning. This experiment provides useful and realistic conclusions for the optimum spectrum allocation of TV channels in broadcasting satellite systems, as for example, the frequency offset required between cross-polar channels depending on the cross-polar rejection at the receiving antenna, for a certain grade of video signal impairment due to the cross-polar channel interference effects, and taken also into account the noise contribution on the signal     

Feasibility of fishmeal replacement by shrimp head silage protein hydrolysate in Nile tilapia (Oreochromis niloticus L) diets

This study provides information on the use of shrimp head silage protein hydrolysate (SPH) as an alternative protein source for tilapia feeding. Six diets (28% protein, 12% lipid) were prepared where fishmeal protein was replaced at levels of 0 (control), 10, 15, 20, 25 and 30% with the hydrolysate. The diets were supplied to Nile tilapia fry (338 mg initial weight) stocked in plastic recirculating 20 l tanks (10 animals per tank), with three replicates per treatment. After an 8 week experimental period, fish fed the diets containing 10 and 15% SPH showed significantly better performance in terms of final body weight, weight gain (%), mean daily weight gain (mg day^?1), specific growth ratio and feed conversion ratio than those fed the control diet (fishmeal as protein source) and higher‐SPH diets. It is concluded that shrimp head hydrolysate is a promising alternative protein source for tilapia feeding, improving growth ratio at dietary inclusion levels as high as 15%. In addition, the diets with added shrimp silage protein were well accepted by the fish, which avidly consumed the feed during the experiment. © 2002 Society of Chemical Industry     

NO emission characteristics in counterflow diffusion flame of blended fuel of H2/CO2/Ar

Flame structure and NO emission characteristics in counterflow diffusion flame of blended fuel of H₂/CO₂/Ar have been numerically simulated with detailed chemistry. The combination of H₂, CO₂ and Ar as fuel is selected to clearly display the contribution of hydrocarbon products to flame structure and NO emission characteristics due to the breakdown of CO₂. A radiative heat loss term is involved to correctly describe the flame dynamics especially at low strain rates. The detailed chemistry adopts the reaction mechanism of GRI 2.11, which consists of 49 species and 279 elementary reactions. All mechanisms including thermal, NO₂, N₂O and Fenimore are taken into account to separately evaluate the effects of CO₂ addition on NO emission characteristics. The increase of added CO₂ quantity causes flame temperature to fall since at high strain rates a diluent effect is prevailing and at low strain rates the breakdown of CO₂ produces relatively populous hydrocarbon products and thus the existence of hydrocarbon products inhibits chain branching. It is also found that the contribution of NO production by N₂O and NO₂ mechanisms are negligible and that thermal mechanism is concentrated on only the reaction zone. As strain rate and CO₂ quantity increase, NO production is remarkably augmented. Copyright © 2002 John Wiley & Sons, Ltd.     

An EM‐based adaptive multiple target tracking filter

Tracking targets of interest is one of the major research areas in radar surveillance systems. We formulate the problem as incomplete data estimation and apply EM to the MAP estimate. The resulting filter has a recursive structure analogous to the Kalman filter. The advantage is that the measurement‐update deals with multiple measurements in parallel and the parameter‐update estimates the system parameters on the fly. Experiments tracking separate targets in parallel show that tracking maintenance ratio of the proposed system is better than that of NNF and RMS position error is smaller than that of PDAF. Also, the system parameters are correctly obtained even from incorrect initial values. Copyright © 2001 John Wiley & Sons, Ltd.     

Monoacylglycerols derived from butter oil by Penicillium roquefortii in suspension cultures

Structural isomers of monoacylglycerols (monoglycerides, MAGs) were identified and compared after degradation of butter oil by two strains of Penicillium roquefortii and a commercial lipase from P roquefortii (EC 3.1.1.3) at pH 7.0 and 10 °C. The conditions were selected as they were comparable with those used in the manufacture of blue mould‐ripened cheese. The commercial lipase was selected to compare with the fungal strains in terms of acyl migration. Results showed that the main isomers formed by lipolysis with the commercial lipase were sn‐2 MAGs (64 mol%), whilst spores and emerging mycelia of P roquefortii produced mainly sn‐1(3) MAGs (83–90 mol%). The work reported here may lead to further assessment of different MAG structural isomers as natural preservatives in foods and dairy products. © 2002 Society of Chemical Industry