Known elementary wide-band amplifiers suffer from a fundamental tradeoff between noise figure (NF) and source impedance matching, which limits the NF to values typically above 3 dB. Global negative ...feedback can be used to break this tradeoff, however, at the price of potential instability. In contrast, this paper presents a feedforward noise-canceling technique, which allows for simultaneous noise and impedance matching, while canceling the noise and distortion contributions of the matching device. This allows for designing wide-band impedance-matching amplifiers with NF well below 3 dB, without suffering from instability issues. An amplifier realized in 0.25-/spl mu/m standard CMOS shows NF values below 2.4 dB over more than one decade of bandwidth (i.e., 150-2000 MHz) and below 2 dB over more than two octaves (i.e., 250-1100 MHz). Furthermore, the total voltage gain is 13.7 dB, the -3-dB bandwidth is from 2 MHz to 1.6 GHz, the IIP2 is +12 dBm, and the IIP3 is 0 dBm. The LNA drains 14 mA from a 2.5-V supply and the die area is 0.3/spl times/0.25 mm/sup 2/.
This paper presents a methodology that systematically generates all 2-MOS-transistor wide-band amplifiers, assuming that MOSFET is exploited as a voltage-controlled current source. This leads to new ...circuits. Their gain and noise factor have been compared to well-known wide-band amplifiers. One of the new circuits appears to have a relatively low noise factor, which is also gain independent. Based on this new circuit, a 50-900 MHz variable-gain wide-band LNA has been designed in 0.35-/spl mu/m CMOS. Measurements show a noise figure between 4.3 and 4.9 dB for gains from 6 to 11 dB. These values are more than 2 dB lower than the noise figure of the wide-band common-gate LNA for the same input matching, power consumption, and voltage gain. IIP2 and IIP3 are better than 23.5 and 14.5 dBm, respectively, while the LNA drains only 1.5 mA at 3.3 V.
Noise cancelling in wideband CMOS LNAs Bruccoleri, F; Klumperink, E A M; Nauta, B
Digest of technical papers - IEEE International Solid-State Circuits Conference,
01/2002
Journal Article
Techniques of noise cancellation in wideband CMOS low noise amplifiers (LNA) were presented. Elementary wideband amplifiers showed a severe trade-off between their frequencies and the matching ...requirement Z sub(IN)=R sub(S), failing to achieve sub-3dB noise figure (NF). The LNA for 2dB wideband NF used 0.25 mu m CMOS, while driving the output bond pad capacitance C sub(LOAD )=0.2 pF load.
Finding all elementary circuits exploiting transconductance Klumperink, E.A.M.; Bruccoleri, F.; Nauta, B.
IEEE transactions on circuits and systems. 2, Analog and digital signal processing,
2001-Nov., 2001-11-00, 20011101, Letnik:
48, Številka:
11
Journal Article
Odprti dostop
Commonly used elementary circuits like single-transistor amplifier stages, the differential pair, and current mirrors basically exploit the transconductance property of transistors. This paper aims ...at finding all elementary transconductance-based circuits. For this purpose, all graphs of two-port circuits with one or two voltage controlled current sources are generated systematically. This results in 150 graphs of "finite transactance two-port circuits" with at least one nonzero transmission parameter. Each of them can be implemented in various ways using transistors and resistors, covering many commonly required types of two-ports. To illustrate the usefulness of the technique several alternative circuit implementations for current amplifiers and voltage followers are generated. A new wide-band low-noise amplifier generated with the technique was realized in 0.35-/spl mu/m CMOS.
Backgrounds/Aims: Knowledge of the proportion of liver cirrhosis attributable to the main risk factors is largely based on methodologically questionable clinical reports.
Methods: The proportion of ...newly diagnosed cases of symptomatic liver cirrhosis attributable to known risk factors was estimated by a case-control study performed during 1989–1996 in 23 medical divisions of several hospitals distributed throughout Italy. Cases were 462 inpatients with cirrhosis admitted for the first time for liver decompensation. Controls were 651 patients admitted during the same period and to the same hospitals as the cases, for acute diseases unrelated to alcohol and virus infection. The proportion of symptomatic liver cirrhosis cases due to alcohol intake and hepatitis B and C viruses and the combination of these was expressed as the population attributable risk.
Results: Attributable risks were 67.9% (95% confidence interval (CI): 53.8–79.4) for alcohol, 40.1% (95% CIL 35.3–45.2) for hepatitis C virus and 4.4% (95% CI: 2.5–7.6) for hepatitis B virus. The three factors together explained 98.1% (95% CI: 81.6–99.6) of cases in men and 67.0% (95% CI: 50.4–85.8) in women.
Conclusions: Alcohol is the risk factor with the highest impact on symptomatic liver cirrhosis risk in Italy. From a public health viewpoint, with the elimination of the well-known risk factors (particularly alcohol and hepatitis C virus), liver cirrhrosis should become a rare disease.
The paper presents the design and analyzes the applications of a microsystem to be used for emulating, in real time, early vision tasks, such as stereo depth estimation and motion analysis. All the ...required computations are based on linear filtering operations with Gabor-like kernels. Full control on the parameters (phase, frequency, and spatial extension) of the kernel can be obtained by introducing a 2nd-order 1-D lattice network that can be mapped with efficiency on an array of simple cells, implemented as analog CMOS VLSI circuits, using continuously adjustable transconductors.
Female Sex and the Risk of Liver Cirrhosis Corrao, G.; Aricò, S.; Zambon, A. ...
Scandinavian journal of gastroenterology,
1997, Letnik:
32, Številka:
11
Journal Article
Recenzirano
Corrao G, Aricò S, Zambon A, Torchio P, di Orio F, Collaborative Groups for the Study of Liver Diseases in Italy. Female sex and the risk of liver cirrhosis. Scand J Gastroenterol 1997 32:1174-1180.
...Background: Evidence on gender-related differences in susceptibility to alcohol-induced liver diseases is questionable with regard to both methodologic and clinical aspects. With the aim to assess the role of gender in the risk of liver cirrhosis, independently and in combination with known risk factors, data from three case-control studies performed in various Italian areas were analysed. Methods: The cases were 462 cirrhotic patients (300 men and 162 women) admitted for the first time to hospital for liver decompensation. Controls were 651 patients (355 men and 296 women) admitted to the same hospitals during the same period as the cases, for acute diseases unrelated to alcohol. Alcohol consumption was expressed as lifetime daily alcohol intake. Results: A significant and independent associations between alcohol intake, chronic hepatitis B and C virus infections, and the risk of liver cirrhosis was observed. The effect of alcohol intake was multiplicatively increased in women. The odds ratio (OR) increased from 1.0 (reference category: men, lifetime abstainers) to 31.4 (95% confidence interval (CI), 10.3-95.8) in men drinking more than 100 g/day of alcohol, and from 2.2 (95% CI, 1.0-7.1) in abstaining women to 44.8 (95% CI, 8.2-224.0) in women drinking more than 100 g/day of alcohol. An increased risk of liver cirrhosis associated with female gender independently of alcohol consumption and virus infection was also observed. Conclusions: A higher susceptibility to alcohol-induced liver diseases was confirmed for women, and an independent effect of female sex on the risk of cirrhosis was observed. Besides alcohol and viruses, some unknown gender-related factor might then be involved in the occurrence of the disease.
Background/Aims: In order to evaluate the association between alcohol intake and the risk of liver cirrhosis in the absence of B and C hepatitis viruses, we analyzed data from three hospital-based ...case-control studies performed in various Italian areas.
Methods: From the case and control series we excluded HBsAg and/or anti-HCV positive patients. Cases were 221 cirrhotic patients admitted for the first time to hospital for liver decompensation. Controls were 614 patients admitted to the same hospitals during the same period as the cases for acute diseases unrelated to alcohol. Alcohol consumption was expressed as lifetime daily alcohol intake (LDAI).
Results: We found a dose-effect relationship between LDAI and the risk of liver cirrhosis (LC). Considering the extreme LDAI categories (LDAI=0 g: lifetime teetotallers and LDAI≥100 g), the LC odds ratio (OR) increased from 1.0 (reference category) to 44.7 (95% confidence interval: 95% CI: 20.0–99.9). An increased risk of LC associated with the female gender independent of alcohol consumption was also observed (OR=2.9; 95% CI: 1.8–4.6).
Conclusions: Alcohol intake acts as a risk factor for symptomatic liver cirrhosis also in the absence of HBV and/or HCV infection. Besides alcohol and viruses, some unknown gender-related factors might be involved in the occurrence of the disease.
Although alcohol intake and hepatitis B and C virus (HBV and HCV) infections are the major determinants of liver cirrhosis (LC) in western countries, the joint effect of these factors on LC risk has ...not yet been adequately studied. Data from three case-control studies performed in Italy were used. Cases were 462 cirrhotic patients admitted to Hospitals for liver decompensation. Controls were 651 inpatients admitted for acute diseases unrelated to alcohol. Alcohol consumption was expressed as lifetime daily alcohol intake (LDAI). Three approaches were used to explore the interaction structure. The Breslow and Storer parametric family of relative risk functions showed that an intermediate structure of interaction from additive to multiplicative was the most adequate one. The Rothman synergism index showed that the interaction structure between LDAI and viral status differed significantly from the additive model in particular for high levels of alcohol intake. When multiple regression additive and multiplicative models were compared after adjustment for the known confounding variables, a trend of the interaction structure towards the multiplicative model was observed at increasing levels of consumption. Better methods are needed for assessing mixed interaction structures in conditions characterized by multifactorial etiologies like cirrhosis of the liver.
Dynamic Huffman compression algorithms operate on data-streams with a bounded symbol list. With these algorithms, the complete list of symbols must be contained in main memory or secondary storage. A ...horizontal format transaction database that is streaming can have a very large item list. Many nodes tax both the processing hardware primary memory size, and the processing time to dynamically maintain the tree. This research investigated Huffman compression of a transaction-streaming database with a very large symbol list, where each item in the transaction database schema’s item list is a symbol to compress. The constraint of a large symbol list is, in this research, equivalent to the constraint of a memory-limited machine. A large symbol set will result if each item in a large database item list is a symbol to compress in a database stream. In addition, database streams may have some temporal component spanning months or years. Finally, the horizontal format is the format most suited to a streaming transaction database because the transaction IDs are not known beforehand This research prototypes an algorithm that will compresses a transaction database stream. There are several advantages to the memory limited dynamic Huffman algorithm. Dynamic Huffman algorithms are single pass algorithms. In many instances a second pass over the data is not possible, such as with streaming databases. Previous dynamic Huffman algorithms are not memory limited, they are asymptotic to O(n), where n is the number of distinct item IDs. Memory is required to grow to fit the n items. The improvement of the new memory limited Dynamic Huffman algorithm is that it would have an O(k) asymptotic memory requirement; where k is the maximum number of nodes in the Huffman tree, k < n, and k is a user chosen constant. The new memory limited Dynamic Huffman algorithm compresses horizontally encoded transaction databases that do not contain long runs of 0’s or 1’s.
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