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| 2. |
- Nilsson, Peter, et al.
(author)
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A Custom Digital Intermediate Frequency Filter for the American Mobile Telephone System
- 1997
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In: IEEE Journal of Solid-State Circuits. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9200. ; 32:6, s. 806-815
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Journal article (peer-reviewed)abstract
- A digital filter for intermediate frequency filtering in mobile communication systems is presented. The purpose of the work is to show an alternative to the analog filters which are used in most of today's heterodyne receivers. Bit-serial arithmetic is applied on a twelfth-order wave digital lattice filter algorithm. The paper also shows a method for retiming such algorithms. The power consumption in two fabricated prototypes is compared. By customizing the library cells, the power consumption has been reduced significantly. In the low power prototype, the power dissipation is 8 mW using 3 V supply voltage. The prototype is a 10 MIPS design fabricated in a 0.8-μm standard two-metal-layer CMOS process
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| 3. |
- Nilsson, Peter, et al.
(author)
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A Monolithic Digital Clock-Generator for On-Chip Clocking of Custom DSP's
- 1996
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In: IEEE Journal of Solid-State Circuits. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9200. ; 31:5, s. 700-706
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Journal article (peer-reviewed)abstract
- This paper shows a robust and easily implemented clock generator for custom designs. It is a fully digital design suitable for both high-speed clocking and low-voltage applications. This clocking method is digital, and it avoids analog methods like phase locked loops or delay line loops. Instead, the clock generator is based on a ring counter which stops a ring oscillator after the correct number of cycles. Both a 385 MHz clock and a 15 MHz custom DSP application using the on-chip clocking strategy are described. The prototypes have been fabricated in a 0.8 μm standard CMOS process. The major advantages with this clocking method are robustness, small size, low-power consumption, and that it can operate at a very low supply voltage
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| 4. |
- Nilsson, Peter, et al.
(author)
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Method to Save Silicon Area by Increasing the Filter Order
- 1995
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In: Electronics Letters. - 1350-911X. ; 31:6, s. 439-441
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Journal article (peer-reviewed)abstract
- The authors' intention is to show that there are other criteria when optimising digital filters than minimising the filter order. The final result in the form of minimum silicon area or few machine cycles in a high-speed custom DSP are aims that are important in a custom design process. It is not an axiom that the minimum order of the filter gives the optimum result. Algorithms with trivial coefficients will gain both in area and speed. As an example, they show a wideband digital filter for mobile communication
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| 5. |
- Olsson, Thomas, et al.
(author)
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A digitally controlled on-chip clock multiplier for globally asynchronous locally synchronous systems
- 1999
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In: Circuits and Systems, 1999. 42nd Midwest Symposium on. ; 1, s. 84-87
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Conference paper (peer-reviewed)abstract
- For large high-speed globally synchronous ASICs, designing the clock distribution net becomes a troublesome task. Besides problems caused by clock skew, the clock net also is a major source of power consumption. Partitioning the design into locally clocked blocks reduces clock skew problems and if handled correctly it also helps reducing power consumption. However, to achieve these positive effects, the blocks need on-chip clocks having properties as small area and low power consumption. Therefore, a low power small area digitally controlled on-chip clock generator is designed
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| 6. |
- Roth, Bengt, et al.
(author)
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Biochemical and ultra-structural reactions to parenteral nutrition with two different fat emulsions in rats
- 1998
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In: Intensive Care Medicine. - : Springer Science and Business Media LLC. - 0342-4642 .- 1432-1238. ; 24:7, s. 716-724
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To compare the effects on fat metabolism and Kupffer cell morphology by total parenteral nutrition (TPN) with two different fat emulsions. DESIGN: Thirty-two male Sprague-Dawley rats, divided into three groups, were investigated. Rats fed orally were used as a reference group, and a group of rats receiving TPN with fat emulsions containing pure long-chain triglycerides (LCT) was compared to a group of rats receiving fat emulsions containing both long-chain triglycerides and medium-chain triglycerides (MCT/LCT). The TPN regimens were equicaloric and administered continuously via a jugular catheter for 10 days. INTERVENTIONS: After suffocation, blood of the rats was collected for the determination of serum lipids. Epididymal fat and heart were collected for the analysis of lipoprotein lipase (LPL) activities, and liver specimens were saved for analyses of hepatic triglyceride concentration, as well as activities of hepatic lipase (HL) and lysosomal enzymes. Light and electron microscopy were used for examination of the Kupffer cell reaction. RESULTS: Directly after termination of parenteral feeding, the levels of serum triglycerides and high density lipoprotein (HDL) triglycerides were higher in the MCT/LCT group than in the LCT group, while no differences concerning cholesterol and phospholipid concentrations were found. No significant difference in liver steatosis was found between the two TPN groups. Comparison of the TPN groups showed that the MCT/ LCT group had significantly decreased LPL activity in adipose tissue, while the LCT group had significantly increased LPL activity in the heart. The activity of HL was low in both groups, but significantly lower in the LCT group. Lipid accumulation and an increased number of lysosomes were found in all Kupffer cell when TPN with LCTemulsions was used. Moreover, TPN induced a pronounced increase in various liver lysosomal enzyme activities, but there was no notable difference between LCT and MCT/LCT effects. CONCLUSIONS: Compared to treatment with pure LCTemulsions, treatment with MCT/LCT emulsions evoked weaker biochemical reactions in terms of lower activity of lipoprotein lipase in fat and heart together with higher serum and HDL triglyceride levels. Morphological signs of increased Kupffer cell activity such as the appearance of multiple lysosomes and fat vacuoles in the cytoplasm followed treatment with pure LCT emulsions. However, both TPN groups showed a marked increase in activities of liver lysosomal enzymes.
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| 7. |
- Roth, Bengt, et al.
(author)
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Lipid deposition in Kupffer cells after parenteral fat nutrition in rats: a biochemical and ultrastructural study
- 1996
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In: Intensive Care Medicine. - 0342-4642. ; 22:11, s. 1224-1231
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To study fat metabolism and evaluate lipid deposition in hepatocytes and Kupffer cells during parenteral nutrition (PN) with or without fat. DESIGN: 20 male Sprague-Dawley rats, divided into four groups, were investigated. Rats fed orally were used as a reference group and compared to three groups of rats receiving PN either without fat or with 33% of non-protein energy as fat or with 66% of non-protein energy as fat. The PN regimens were equicaloric and administered continuously via a jugular catheter for 7 days. INTERVENTIONS: After suffocation, blood was collected for determination of serum lipids. Epididymal fat and heart were collected for analysis of lipoprotein lipase activities, and pieces of liver were saved for analyses of liver triglyceride concentration and hepatic lipase activity. Light and electron microscopy were used for examination of lipid deposition in Kupffer cells. RESULTS: Directly after termination of parenteral feeding, the serum levels of triglycerides were similar in all PN groups, while the levels of non-high-density lipoprotein (HDL) cholesterol and non-HDL phospholipids were significantly increased in parallel with increased doses of fat. Lipid-free PN resulted in significantly less liver steatosis than high-fat PN. Lipid PN also resulted in downregulated hepatic lipase activity, signs of lipid accumulation in Kupffer cells and hepatocytes and an increased number of phagosomes in Kupffer cells. CONCLUSIONS: Fat vacuoles were found in Kupffer cells after lipid PN, although serum levels of triglycerides were not elevated and lipoprotein lipase activity were not depressed. The cells were distended by fat vacuoles after administration of PN solutions with a high fat concentration. Morphological signs of increased Kupffer cell activity were also found, suggesting that intravenous fat emulsions may activate macrophages.
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